SherbyNet - /page/wikibook/entry.mu

Micron Document

<!DOCTYPE html>

<title>Contrail</title>

</head>

<span id="openzim-page-title" class="mw-page-title-main"><span class="mw-page-title-main">Contrail</span></span>

</h1>

</header>

/* start https://en.wikipedia.org/ */

.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}

/* end https://en.wikipedia.org/ */

</style><div role="note" class="hatnote navigation-not-searchable"><span>"Vapor trail" redirects here. For other uses, see <a href="Vapor_Trail_(disambiguation)" class="mw-disambig" title="Vapor Trail (disambiguation)">Vapor Trail (disambiguation)</a>.</span> <span>Not to be confused with <a href="Chemtrail_conspiracy_theory" title="Chemtrail conspiracy theory">Chemtrail conspiracy theory</a>.</span> <span>For other uses, see <a href="Contrail_(disambiguation)" class="mw-disambig" title="Contrail (disambiguation)">Contrail (disambiguation)</a>.</span></div>

</p>

/* start https://en.wikipedia.org/ */

.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}@media screen{html.skin-theme-clientpref-night .mw-parser-output .infobox-full-data:not(.notheme)>div:not(.notheme)[style]{background:#1f1f23!important;color:#f8f9fa}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .infobox-full-data:not(.notheme)>div:not(.notheme)[style]{background:#1f1f23!important;color:#f8f9fa}}@media(min-width:640px){body.skin--responsive .mw-parser-output .infobox-table{display:table!important}body.skin--responsive .mw-parser-output .infobox-table>caption{display:table-caption!important}body.skin--responsive .mw-parser-output .infobox-table>tbody{display:table-row-group}body.skin--responsive .mw-parser-output .infobox-table th,body.skin--responsive .mw-parser-output .infobox-table td{padding-left:inherit;padding-right:inherit}}

/* end https://en.wikipedia.org/ */

</style><table class="infobox"><tbody><tr><th colspan="2" class="infobox-above">Contrails</th></tr><tr><td colspan="2" class="infobox-image"><div class="infobox-caption">A jet forming contrails in a blue sky</div></td></tr><tr><th scope="row" class="infobox-label"><a href="Cloud#Families_and_cross-classification_into_genera" title="Cloud">Genus</a></th><td class="infobox-data">Cirrus (<i>curl of hair</i>), cirrocumulus, or cirrostratus</td></tr><tr><th scope="row" class="infobox-label">Altitude</th><td class="infobox-data">7,500 to 12,000 m<br> (25,000 to 40,000 ft)</td></tr><tr><th scope="row" class="infobox-label"><a href="Cloud#Summary_of_families,_genera,_species,_and_associated_weather" title="Cloud">Classification</a></th><td class="infobox-data">Family A (High-level)</td></tr><tr><th scope="row" class="infobox-label">Appearance</th><td class="infobox-data">Long bands</td></tr><tr><th scope="row" class="infobox-label"><a href="Cloud_types" class="mw-redirect" title="Cloud types">Precipitation</a></th><td class="infobox-data">No</td></tr></tbody></table>

<p><b>Contrails</b> (<span class="rt-commentedText nowrap"><span class="IPA nopopups noexcerpt" lang="en-fonipa">/<span style="border-bottom:1px dotted"><span title="/ˈ/: primary stress follows">ˈ</span><span title="'k' in 'kind'">k</span><span title="/ɒ/: 'o' in 'body'">ɒ</span><span title="'n' in 'nigh'">n</span><span title="'t' in 'tie'">t</span><span title="'r' in 'rye'">r</span><span title="/eɪ/: 'a' in 'face'">eɪ</span><span title="'l' in 'lie'">l</span><span title="'z' in 'zoom'">z</span></span>/</span></span>; short for "<b>condensation trails</b>") or <b>vapour trails</b> are line-shaped <a href="Clouds" class="mw-redirect" title="Clouds">clouds</a> produced by <a href="Aircraft" title="Aircraft">aircraft</a> engine exhaust or changes in <a href="Air_pressure" class="mw-redirect" title="Air pressure">air pressure</a>, typically at aircraft cruising altitudes several kilometres/miles above the <a href="Earth" title="Earth">Earth's</a> surface. They are composed primarily of <a href="Water" title="Water">water</a>, in the form of <a href="Ice_crystal" title="Ice crystal">ice crystals</a>. The combination of <a href="Water_vapor" title="Water vapor">water vapor</a> in aircraft engine exhaust and the low ambient temperatures at high altitudes causes the trails' formation.

</p><p><a href="Chemical_impurity" title="Chemical impurity">Impurities</a> in the engine exhaust from the fuel, including <a href="Soot" title="Soot">soot</a> and <a href="Sulfur" title="Sulfur">sulfur</a> compounds (0.05% by weight in jet fuel) provide some of the particles that serve as <a href="Cloud_condensation_nuclei" title="Cloud condensation nuclei">cloud condensation nuclei</a> for <a href="Water_droplet" class="mw-redirect" title="Water droplet">water droplet</a> growth in the exhaust. If water droplets form, they can freeze to form ice particles that compose a contrail.<sup id="cite_ref-FAA.GOV_1-0" class="reference"><a href="#cite_note-FAA.GOV-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> Their formation can also be triggered by changes in air pressure in <a href="Wingtip_vortices" title="Wingtip vortices">wingtip vortices</a>, or in the air over the entire wing surface.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> Contrails, and other clouds caused directly by human activity, are called <i><b>homogenitus</b></i>.<sup id="cite_ref-ICA2017_3-0" class="reference"><a href="#cite_note-ICA2017-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup>

</p><p>The vapor trails produced by <a href="Rocket" title="Rocket">rockets</a> are referred to as "<b>missile contrails</b>"<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> or "<b>rocket contrails</b>." The water vapor and aerosol produced by rockets promote the "formation of <a href="Ice_cloud" title="Ice cloud">ice clouds</a> in ice <a href="Supersaturation" title="Supersaturation">supersaturated</a> layers of the atmosphere."<sup id="cite_ref-:0_5-0" class="reference"><a href="#cite_note-:0-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> Missile contrail clouds mainly comprise "<a href="Oxide" title="Oxide">metal oxide</a> particles, high-temperature water vapor condensation particles, and other byproducts of <a href="Rocket_engine" title="Rocket engine">engine combustion</a>."<sup id="cite_ref-:0_5-1" class="reference"><a href="#cite_note-:0-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup>

</p><p>Depending on the temperature and humidity at the altitude where the contrails form, they may be visible for only a few seconds or minutes, or may persist for hours and spread to be several kilometres/miles wide, eventually resembling natural <a href="Cirrus_cloud" title="Cirrus cloud">cirrus</a> or <a href="Altocumulus" class="mw-redirect" title="Altocumulus">altocumulus</a> clouds.<sup id="cite_ref-FAA.GOV_1-1" class="reference"><a href="#cite_note-FAA.GOV-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> <b>Persistent contrails</b> are of particular interest to scientists because they increase the cloudiness of the atmosphere.<sup id="cite_ref-FAA.GOV_1-2" class="reference"><a href="#cite_note-FAA.GOV-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> The resulting cloud forms are formally described as <b>homomutatus</b>,<sup id="cite_ref-ICA2017_3-1" class="reference"><a href="#cite_note-ICA2017-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> and may resemble cirrus, cirrocumulus, or cirrostratus, and are sometimes called <b>cirrus aviaticus</b>.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> Some persistent spreading contrails contribute to <a href="Climate_change" title="Climate change">climate change</a>.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup>

</p>

<div class="mw-heading mw-heading2"><h2 id="Condensation_trails_as_a_result_of_engine_exhaust">Condensation trails as a result of engine exhaust</h2></div>

<p>Engine exhaust is predominantly made up of water and carbon dioxide, the combustion products of hydrocarbon fuels. Many other chemical byproducts of incomplete hydrocarbon fuel combustion, including <a href="Volatile_organic_compounds" class="mw-redirect" title="Volatile organic compounds">volatile organic compounds</a>, <a href="Inorganic_compound" title="Inorganic compound">inorganic</a> gases, <a href="Polycyclic_aromatic_hydrocarbons" class="mw-redirect" title="Polycyclic aromatic hydrocarbons">polycyclic aromatic hydrocarbons</a>, <a href="Oxide" title="Oxide">oxygenated</a> organics, <a href="Alcohols" class="mw-redirect" title="Alcohols">alcohols</a>, <a href="Ozone" title="Ozone">ozone</a> and particles of soot have been observed at lower concentrations. The exact quality is a function of engine type and basic combustion engine function, with up to 30% of aircraft exhaust being unburned fuel.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> (Micron-sized metallic particles resulting from engine wear have also been detected.) At high altitudes as this water vapor emerges into a cold environment, the localized increase in water vapor can raise the <a href="Relative_humidity" class="mw-redirect" title="Relative humidity">relative humidity</a> of the air past <a href="Dew_point" title="Dew point">saturation point</a>. The vapor then condenses into tiny water droplets which freeze if the temperature is low enough. These millions of tiny water droplets and/or ice crystals form the contrails. The time taken for the vapor to cool enough to condense accounts for the contrail forming some distance behind the aircraft. At high altitudes, supercooled water vapor requires a trigger to encourage deposition or condensation. The exhaust particles in the aircraft's exhaust act as this trigger, causing the trapped vapor to condense rapidly. Exhaust contrails usually form at high altitudes; usually above 8,000 m (26,000 ft), where the air temperature is below −36.5 <a href="Celsius" title="Celsius">°C</a> (−34 <a href="Fahrenheit" title="Fahrenheit">°F</a>). They can also form closer to the ground when the air is cold and moist.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup>

</p><p>A 2013–2014 study jointly supported by NASA, the German aerospace center DLR, and Canada's National Research Council NRC, determined that <a href="Biofuel" title="Biofuel">biofuels</a> could reduce contrail generation. This reduction was explained by demonstrating that biofuels produce fewer soot particles, which are the nuclei around which the ice crystals form. The tests were performed by flying a <a href="Douglas_DC-8" title="Douglas DC-8">DC-8</a> at cruising altitude with a sample-gathering aircraft flying in trail. In these samples, the contrail-producing soot particle count was reduced by 50 to 70 percent, using a 50% blend of conventional Jet A1 fuel and HEFA (hydroprocessed esters and fatty acids) biofuel produced from <a href="Camelina" title="Camelina">camelina</a>.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup>

</p>

<div class="mw-heading mw-heading2"><h2 id="Condensation_from_decreases_in_pressure">Condensation from decreases in pressure</h2></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Wingtip_vortices" title="Wingtip vortices">Wingtip vortices</a></div>

<p>As a wing generates <a href="Lift_(force)" title="Lift (force)">lift</a>, it causes a <a href="Vortex" title="Vortex">vortex</a> to form at the wingtip, and at the tip of the <a href="Flap_(aircraft)" class="mw-redirect" title="Flap (aircraft)">flap</a> when deployed (wingtips and flap boundaries represent discontinuities in airflow). These <a href="Wingtip_vortices" title="Wingtip vortices">wingtip vortices</a> persist in the atmosphere long after the aircraft has passed. The reduction in pressure and temperature across each vortex can cause water to condense and make the cores of the wingtip vortices visible; this effect is more common on humid days. Wingtip vortices can sometimes be seen behind the wing flaps of airliners during takeoff and landing, and during <a href="Space_Shuttle" title="Space Shuttle">Space Shuttle</a> landings.

</p><p>The visible cores of wingtip vortices contrast with the other major type of contrails which are caused by the combustion of fuel. Contrails produced from jet engine exhaust are seen at high altitude, directly behind each engine. By contrast, the visible cores of wingtip vortices are usually seen only at low altitude where the aircraft is travelling slowly after takeoff or before landing, and where the ambient humidity is higher; they trail behind the wingtips and wing flaps rather than behind the engines.

</p><p>At high-thrust settings the fan blades at the intake of a <a href="Jet_engine#Turbofan" title="Jet engine">turbofan engine</a> reach <a href="Transonic" title="Transonic">transonic</a> speeds, causing a sudden drop in air pressure. This creates the condensation fog (inside the intake) which is often observed by air travelers during takeoff.

</p><p>The tips of rotating surfaces (such as <a href="Propeller_(aeronautics)" title="Propeller (aeronautics)">propellers</a> and <a href="Helicopter_rotor" title="Helicopter rotor">rotors</a>) sometimes produce visible contrails.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup>

</p><p>In firearms, a vapor trail is sometimes observed when firing under rare conditions, due to condensation induced by changes in air pressure around the bullet.<sup id="cite_ref-snipercountry_15-0" class="reference"><a href="#cite_note-snipercountry-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> A vapor trail from a bullet is observable from any direction.<sup id="cite_ref-snipercountry_15-1" class="reference"><a href="#cite_note-snipercountry-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> Vapor trail should not be confused with bullet trace, a refractive effect due to changes in air pressure as the bullet travels, which is a much more common phenomenon (and is usually only observable directly from behind the shooter).<sup id="cite_ref-snipercountry_15-2" class="reference"><a href="#cite_note-snipercountry-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup>

</p>

<div class="mw-heading mw-heading2"><h2 id="Impacts_on_climate">Impacts on climate</h2></div>

<p>It is considered that the largest contribution of aviation to climate change comes from contrails.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup>

In general, aircraft contrails trap <a href="Outgoing_longwave_radiation" title="Outgoing longwave radiation">outgoing longwave radiation</a> emitted by the Earth and atmosphere more than they reflect incoming <a href="Solar_radiation" class="mw-redirect" title="Solar radiation">solar radiation</a>, resulting in a net increase in <a href="Radiative_forcing" title="Radiative forcing">radiative forcing</a>. In 1992, this warming effect was estimated between 3.5 mW/m<sup>2</sup> and 17 mW/m<sup>2</sup>.<sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup>

In 2009, its 2005 value was estimated at 12 mW/m<sup>2</sup>, based on the <a href="Atmospheric_reanalysis" title="Atmospheric reanalysis">reanalysis</a> data, <a href="Climate_model" title="Climate model">climate models</a>, and <a href="Atmospheric_radiative_transfer_codes" title="Atmospheric radiative transfer codes">radiative transfer codes</a>; with an uncertainty range of 5 to 26 mW/m<sup>2</sup>, and with a low level of scientific understanding.<sup id="cite_ref-20" class="reference"><a href="#cite_note-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup>

</p>

<p>Contrail cirrus may be air traffic's largest radiative forcing component, larger than all CO<sub style="font-size: 80%;vertical-align: -0.35em">2</sub> accumulated from aviation, and could triple from a 2006 baseline to 160–180 mW/m<sup>2</sup> by 2050 without intervention.<sup id="cite_ref-21" class="reference"><a href="#cite_note-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-22" class="reference"><a href="#cite_note-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> For comparison, the total radiative forcing from human activities amounted to 2.72 W/m<sup>2</sup> (with a range between 1.96 and 3.48W/m<sup>2</sup>) in 2019, and the increase from 2011 to 2019 alone amounted to 0.34W/m<sup>2</sup>.<sup id="cite_ref-IPCC_WGI_SPM_23-0" class="reference"><a href="#cite_note-IPCC_WGI_SPM-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> Contrail effects differ a lot depending on when they are formed, as they decrease the daytime temperature and increase the nighttime temperature, reducing their difference.<sup id="cite_ref-24" class="reference"><a href="#cite_note-24"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> In 2006, it was estimated that <a href="Red-eye_flight" title="Red-eye flight">night flights</a> contribute 60 to 80% of contrail radiative forcing while accounting for 25% of daily air traffic, and winter flights contribute half of the annual mean radiative forcing while accounting for 22% of annual air traffic.<sup id="cite_ref-25" class="reference"><a href="#cite_note-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup>

</p><p>Starting from the 1990s, it was suggested that contrails during daytime have a strong cooling effect, and when combined with the warming from night-time flights, this would lead to a substantial <a href="Diurnal_temperature_variation" title="Diurnal temperature variation">diurnal temperature variation</a> (the difference in the day's highs and lows at a fixed station).<sup id="cite_ref-26" class="reference"><a href="#cite_note-26"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup> When <a href="Closings_and_cancellations_following_the_September_11_attacks" title="Closings and cancellations following the September 11 attacks">no commercial aircraft flew</a> across the USA following the <a href="September_11_attacks" title="September 11 attacks">September 11 attacks</a>, the <a href="Diurnal_temperature_variation" title="Diurnal temperature variation">diurnal temperature variation</a> was widened by 1.1 °C (2.0 °F).<sup id="cite_ref-Travis2002Aug_27-0" class="reference"><a href="#cite_note-Travis2002Aug-27"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> Measured across 4,000 <a href="Weather_station" title="Weather station">weather stations</a> in the continental United States, this increase was the largest recorded in 30 years.<sup id="cite_ref-Travis2002Aug_27-1" class="reference"><a href="#cite_note-Travis2002Aug-27"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> Without contrails, the local diurnal temperature range was 1 °C (1.8 °F) higher than immediately before.<sup id="cite_ref-28" class="reference"><a href="#cite_note-28"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup> In the southern US, the difference was diminished by about 3.3 °C (6 °F), and by 2.8 °C (5 °F) in the US midwest.<sup id="cite_ref-29" class="reference"><a href="#cite_note-29"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-contrails_30-0" class="reference"><a href="#cite_note-contrails-30"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup> However, follow-up studies found that a natural change in cloud cover can more than explain these findings.<sup id="cite_ref-31" class="reference"><a href="#cite_note-31"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup> The authors of a 2008 study wrote, "The variations in high cloud cover, including contrails and contrail-induced cirrus clouds, contribute weakly to the changes in the diurnal temperature range, which is governed primarily by lower altitude clouds, winds, and humidity."<sup id="cite_ref-32" class="reference"><a href="#cite_note-32"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup>

</p>

<p>In 2011, a study of British meteorological records taken during <a href="World_War_II" title="World War II">World War II</a> identified one event where the temperature was 0.8 °C (1.4 °F) higher than the day's average near <a href="Airbase" class="mw-redirect" title="Airbase">airbases</a> used by <a href="USAAF" class="mw-redirect" title="USAAF">USAAF</a> <a href="Strategic_bomber" title="Strategic bomber">strategic bombers</a> after they flew in a formation. However, its authors cautioned that this was a single event, making it difficult to draw firm conclusions from it.<sup id="cite_ref-33" class="reference"><a href="#cite_note-33"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-34" class="reference"><a href="#cite_note-34"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-35" class="reference"><a href="#cite_note-35"><span class="cite-bracket">[</span>35<span class="cite-bracket">]</span></a></sup> Then, the global response to the <a href="2020_coronavirus_pandemic" class="mw-redirect" title="2020 coronavirus pandemic">2020 coronavirus pandemic</a> led to a reduction in global air traffic of nearly 70% relative to 2019. Thus, it provided an extended opportunity to study the impact of contrails on regional and global temperature. Multiple studies found "no significant response of diurnal surface air temperature range" as the result of contrail changes, and either "no net significant global ERF" (effective <a href="Radiative_forcing" title="Radiative forcing">radiative forcing</a>) or a very small warming effect.<sup id="cite_ref-36" class="reference"><a href="#cite_note-36"><span class="cite-bracket">[</span>36<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-37" class="reference"><a href="#cite_note-37"><span class="cite-bracket">[</span>37<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-38" class="reference"><a href="#cite_note-38"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup>

</p><p>An EU project launched in 2020 aims to assess the feasibility of minimising contrail effects by the operational choices in making flight plans.<sup id="cite_ref-39" class="reference"><a href="#cite_note-39"><span class="cite-bracket">[</span>39<span class="cite-bracket">]</span></a></sup> Other similar projects include ContrailNet from Eurocontrol,<sup id="cite_ref-40" class="reference"><a href="#cite_note-40"><span class="cite-bracket">[</span>40<span class="cite-bracket">]</span></a></sup> Reviate,<sup id="cite_ref-41" class="reference"><a href="#cite_note-41"><span class="cite-bracket">[</span>41<span class="cite-bracket">]</span></a></sup> and the Ciconia project,<sup id="cite_ref-42" class="reference"><a href="#cite_note-42"><span class="cite-bracket">[</span>42<span class="cite-bracket">]</span></a></sup> as well as Google's 'project contrails'.<sup id="cite_ref-43" class="reference"><a href="#cite_note-43"><span class="cite-bracket">[</span>43<span class="cite-bracket">]</span></a></sup>

</p>

<div class="mw-heading mw-heading2"><h2 id="Head-on_contrails">Head-on contrails</h2></div>

<p>A contrail from an airplane flying towards the observer can appear to be generated by an object moving vertically.<sup id="cite_ref-NS_44-0" class="reference"><a href="#cite_note-NS-44"><span class="cite-bracket">[</span>44<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-cont_45-0" class="reference"><a href="#cite_note-cont-45"><span class="cite-bracket">[</span>45<span class="cite-bracket">]</span></a></sup> On 8 November 2010 in the US state of <a href="California" title="California">California</a>, a <a href="2010_California_contrail_incident" title="2010 California contrail incident">contrail of this type</a> gained media attention as a "mystery missile" that could not be explained by U.S. military and aviation authorities,<sup id="cite_ref-46" class="reference"><a href="#cite_note-46"><span class="cite-bracket">[</span>46<span class="cite-bracket">]</span></a></sup> and its explanation as a contrail<sup id="cite_ref-NS_44-1" class="reference"><a href="#cite_note-NS-44"><span class="cite-bracket">[</span>44<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-cont_45-1" class="reference"><a href="#cite_note-cont-45"><span class="cite-bracket">[</span>45<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-47" class="reference"><a href="#cite_note-47"><span class="cite-bracket">[</span>47<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-48" class="reference"><a href="#cite_note-48"><span class="cite-bracket">[</span>48<span class="cite-bracket">]</span></a></sup> took more than 24 hours to become accepted by U.S. media and military institutions.<sup id="cite_ref-49" class="reference"><a href="#cite_note-49"><span class="cite-bracket">[</span>49<span class="cite-bracket">]</span></a></sup>

</p>

<div class="mw-heading mw-heading2"><h2 id="Distrails">Distrails</h2></div>

<p>Where an aircraft passes through a cloud, it can disperse the cloud in its path. This is known as a distrail (short for "dissipation trail"). The plane's warm engine exhaust and enhanced vertical mixing in the aircraft's wake can cause existing cloud droplets to evaporate. If the cloud is sufficiently thin, such processes can yield a cloud-free corridor in an otherwise solid cloud layer.<sup id="cite_ref-50" class="reference"><a href="#cite_note-50"><span class="cite-bracket">[</span>50<span class="cite-bracket">]</span></a></sup> An early satellite observation of distrails that most likely were elongated, aircraft-induced <a href="Fallstreak_holes" class="mw-redirect" title="Fallstreak holes">fallstreak holes</a> appeared in Corfidi and Brandli (1986).<sup id="cite_ref-51" class="reference"><a href="#cite_note-51"><span class="cite-bracket">[</span>51<span class="cite-bracket">]</span></a></sup>

</p><p>Clouds form when invisible water vapor condenses into microscopic water droplets or into microscopic ice crystals. This may happen when air with a high proportion of gaseous water cools. A distrail forms when the heat of engine exhaust evaporates the liquid water droplets in a cloud, turning them back into invisible, gaseous water vapor. Distrails also may arise as a result of enhanced mixing (entrainment) of drier air immediately above or below a thin cloud layer following passage of an aircraft through the cloud, as shown in the second image below:

</p>

/* start https://en.wikipedia.org/ */

.mw-parser-output .div-col{margin-top:0.3em;column-width:30em}.mw-parser-output .div-col-small{font-size:90%}.mw-parser-output .div-col-rules{column-rule:1px solid #aaa}.mw-parser-output .div-col dl,.mw-parser-output .div-col ol,.mw-parser-output .div-col ul{margin-top:0}.mw-parser-output .div-col li,.mw-parser-output .div-col dd{page-break-inside:avoid;break-inside:avoid-column}

/* end https://en.wikipedia.org/ */

</style><div class="div-col" style="column-width: 25em;">

<ul><li><a href="Chemtrail_conspiracy_theory" title="Chemtrail conspiracy theory">Chemtrail conspiracy theory</a></li>

<li><a href="Cirrus_cloud" title="Cirrus cloud">Cirrus cloud</a></li>

<li><a href="Cloud_chamber" title="Cloud chamber">Cloud chamber</a> – particle detector that works on similar principle</li>

<li><a href="Environmental_impact_of_aviation" title="Environmental impact of aviation">Environmental impact of aviation</a></li>

<li><a href="Fallstreak_hole" title="Fallstreak hole">Fallstreak hole</a></li>

<li><a href="Global_dimming" title="Global dimming">Global dimming</a></li>

<li><a href="Ship_tracks" title="Ship tracks">Ship tracks</a></li>

<li><a href="Skywriting" title="Skywriting">Skywriting</a></li>

<li><a href="Space_jellyfish" title="Space jellyfish">Space jellyfish</a></li>

<li><a href="Twomey_effect" title="Twomey effect">Twomey effect</a></li></ul>

</div>

<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>

/* start https://en.wikipedia.org/ */

.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}

/* end https://en.wikipedia.org/ */

</style><div class="reflist">

/* start https://en.wikipedia.org/ */

.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("./mw/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("./mw/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("./mw/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("./mw/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}

/* end https://en.wikipedia.org/ */

</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.faa.gov/sites/faa.gov/files/regulations_policies/policy_guidance/envir_policy/contrails.pdf">"Aircraft Contrails Factsheet"</a> <span class="cs1-format">(PDF)</span>. FAA.Gov. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20060928114935/http://www2.faa.gov/regulations_policies/policy_guidance/envir_policy/media/contrails.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 28 September 2006<span class="reference-accessdate">. Retrieved <span class="nowrap">10 September</span> 2023</span>.</cite></span>

</li>

<li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><cite class="citation encyclopaedia cs1"><a rel="nofollow" class="external text" href="https://www.britannica.com/EBchecked/topic/623212/vapour-trail">"vapour trail"</a>. <i>Encyclopædia Britannica</i>. Encyclopædia Britannica Inc<span class="reference-accessdate">. Retrieved <span class="nowrap">17 April</span> 2012</span>.</cite></span>

</li>

<li id="cite_note-ICA2017-3"><span class="mw-cite-backlink">^ <a href="#cite_ref-ICA2017_3-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-ICA2017_3-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><cite id="CITEREFSutherland2017" class="citation news cs1">Sutherland, Scott (23 March 2017). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20220531022305/https://www.theweathernetwork.com/news/articles/cloud-atlas-leaps-into-21st-century-with-12-new-cloud-types/80685/">"Cloud Atlas leaps into 21st century with 12 new cloud types"</a>. <i>The Weather Network</i>. Pelmorex Media. Archived from <a rel="nofollow" class="external text" href="https://www.theweathernetwork.com/news/articles/cloud-atlas-leaps-into-21st-century-with-12-new-cloud-types/80685/">the original</a> on 31 May 2022<span class="reference-accessdate">. Retrieved <span class="nowrap">24 March</span> 2017</span>.</cite></span>

</li>

<li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20250217051509/https://earthobservatory.nasa.gov/blogs/earthmatters/2013/10/17/the-missile-contrail-you-may-have-missed-during-the-shutdown/">"The Russian Missile Contrail You May Have Missed During the Shutdown"</a>. <i>earthobservatory.nasa.gov</i>. <a href="NASA_Earth_Observatory" title="NASA Earth Observatory">NASA Earth Observatory</a>. 17 October 2013. Archived from <a rel="nofollow" class="external text" href="https://earthobservatory.nasa.gov/blogs/earthmatters/2013/10/17/the-missile-contrail-you-may-have-missed-during-the-shutdown/">the original</a> on 17 February 2025<span class="reference-accessdate">. Retrieved <span class="nowrap">28 February</span> 2025</span>.</cite></span>

</li>

<li id="cite_note-:0-5"><span class="mw-cite-backlink">^ <a href="#cite_ref-:0_5-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-:0_5-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><cite id="CITEREFLiFuWei2025" class="citation journal cs1">Li, Chenshuo; Fu, Debin; Wei, Tianyu (21 February 2025). <a rel="nofollow" class="external text" href="https://www.sciencedirect.com/science/article/pii/S2214914725000546">"Random walk dispersion model for missile contrail particles in cross-airspace environments"</a>. <i>Defence Technology</i>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.dt.2025.02.015">10.1016/j.dt.2025.02.015</a>. <a href="ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/2214-9147">2214-9147</a>.</cite></span>

</li>

<li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><cite id="CITEREFVoigtSchumannGraf2016" class="citation journal cs1">Voigt, Ch.; Schumann, U.; Graf, K. (1 July 2016). <a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2016EUCAS...8..183V/abstract">"Contrail formation in the tropopause region caused by emissions from an Ariane 5 rocket"</a>. <i>EUCASS Proceedings Series</i>. <b>8</b>: <span class="nowrap">183–</span>196. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1051%2Feucass%2F201608183">10.1051/eucass/201608183</a>.</cite></span>

</li>

<li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://namesofclouds.com/cirrus/cirrus-aviaticus.html">"Cirrus Aviaticus – Cirrus – Names of Clouds"</a>. <i>namesofclouds.com</i><span class="reference-accessdate">. Retrieved <span class="nowrap">13 October</span> 2021</span>.</cite></span>

</li>

<li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><cite id="CITEREFTimperley" class="citation web cs1">Timperley, Jocelyn. <a rel="nofollow" class="external text" href="https://www.bbc.com/future/article/20210525-how-aviation-is-reducing-its-climate-emissions">"The fastest ways aviation could cut emissions"</a>. <i>www.bbc.com</i><span class="reference-accessdate">. Retrieved <span class="nowrap">11 June</span> 2021</span>.</cite></span>

</li>

<li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><cite id="CITEREFRitchieStillRossi_IiiBekkedal2003" class="citation journal cs1">Ritchie, Glenn; Still, Kenneth; Rossi Iii, John; Bekkedal, Marni; Bobb, Andrew; Arfsten, Darryl (2003). "Biological and health effects of exposure to kerosene-based jet fuels and performance additives". <i>Journal of Toxicology and Environmental Health, Part B</i>. <b>6</b> (4): <span class="nowrap">357–</span>451. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1080%2F10937400306473">10.1080/10937400306473</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/12775519">12775519</a>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:30595016">30595016</a>.</cite></span>

</li>

<li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20160408184845/http://science-edu.larc.nasa.gov/contrail-edu/faq.php">"Contrail Education – FAQ"</a>. <i>nasa.gov</i>. Archived from <a rel="nofollow" class="external text" href="https://science-edu.larc.nasa.gov/contrail-edu/faq.php">the original</a> on 8 April 2016.</cite></span>

</li>

<li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><cite class="citation news cs1"><span class="id-lock-subscription" title="Paid subscription required"><a rel="nofollow" class="external text" href="http://aviationweek.com/technology/week-technology-march-20-24-2017">"The Week in Technology"</a></span>. <i>Aviation Week & Space Technology</i>. 20–24 March 2017. Paper published in <i>Nature</i>, Rich Moore & Hans Schlager, authors.</cite></span>

</li>

<li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><cite id="CITEREFSean_Broderick2017" class="citation news cs1">Sean Broderick (24 December 2017). <a rel="nofollow" class="external text" href="https://www.ainonline.com/aviation-news/business-aviation/2017-12-24/biofuels-could-reduce-contrail-formation-research-finds">"Biofuels Could Reduce Contrail Formation, Research Finds"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">13 October</span> 2021</span>.</cite></span>

</li>

<li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"><cite id="CITEREFRichard_H._Moore2017" class="citation journal cs1">Richard H. Moore; et al. (15 March 2017). <a rel="nofollow" class="external text" href="https://elib.dlr.de/112943/1/Moore_et_al_Nature_2017.pdf">"Biofuel blending reduces particle emissions from aircraft engines at cruise conditions"</a> <span class="cs1-format">(PDF)</span>. <i>Nature</i>. <b>543</b> (7645): <span class="nowrap">411–</span>415. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2017Natur.543..411M">2017Natur.543..411M</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2Fnature21420">10.1038/nature21420</a>. <a href="PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8025803">8025803</a></span>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/28300096">28300096</a>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:4447403">4447403</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20190427124937/https://elib.dlr.de/112943/1/Moore_et_al_Nature_2017.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 27 April 2019.</cite></span>

</li>

<li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20140716081046/http://www.verticalmag.com/digital_issue/2014/v13i2/files/2.html">"Photos from the field"</a>. <i>Vertical Magazine</i>. April–May 2014. p. 39. Archived from <a rel="nofollow" class="external text" href="http://www.verticalmag.com/digital_issue/2014/v13i2/files/2.html">the original</a> on 16 July 2014<span class="reference-accessdate">. Retrieved <span class="nowrap">8 July</span> 2014</span>.</cite></span>

</li>

<li id="cite_note-snipercountry-15"><span class="mw-cite-backlink">^ <a href="#cite_ref-snipercountry_15-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-snipercountry_15-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-snipercountry_15-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.snipercountry.com/bullet-trail/">"Vapor trail and Bullet trace"</a>. <i>Sniper Country</i>. 9 August 2018<span class="reference-accessdate">. Retrieved <span class="nowrap">13 October</span> 2021</span>.</cite></span>

</li>

<li id="cite_note-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-16">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.youtube.com/watch?v=dRWTzTB_8Tg">"Vapor Trail vs Bullet Trace"</a>. <i>YouTube</i>. 18 October 2017<span class="reference-accessdate">. Retrieved <span class="nowrap">13 October</span> 2021</span>.</cite></span>

</li>

<li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text"><cite id="CITEREFNorseman2017" class="citation web cs1">Norseman, Dave the (15 June 2017). <a rel="nofollow" class="external text" href="https://www.breachbangclear.com/language-lessons-trace/">"Language Lessons: TRACE"</a>. <i>Breach Bang Clear</i><span class="reference-accessdate">. Retrieved <span class="nowrap">13 October</span> 2021</span>.</cite></span>

</li>

<li id="cite_note-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-18">^</a></b></span> <span class="reference-text"><cite id="CITEREFKATIE_CAMERO2019" class="citation web cs1">KATIE CAMERO (28 June 2019). <a rel="nofollow" class="external text" href="https://www.science.org/content/article/aviation-s-dirty-secret-airplane-contrails-are-surprisingly-potent-cause-global-warming">"Aviation's dirty secret: Airplane contrails are a surprisingly potent cause of global warming Warming effect of thin, white clouds will triple by 2050"</a>. <i>www.science.org</i><span class="reference-accessdate">. Retrieved <span class="nowrap">10 May</span> 2024</span>.</cite></span>

</li>

<li id="cite_note-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-19">^</a></b></span> <span class="reference-text"><cite id="CITEREFPonater2005" class="citation journal cs1">Ponater, M.; et al. (2005). <a rel="nofollow" class="external text" href="https://doi.org/10.1029%2F2005GL022580">"On contrail climate sensitivity"</a>. <i><a href="Geophysical_Research_Letters" title="Geophysical Research Letters">Geophysical Research Letters</a></i>. <b>32</b> (10): L10706. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2005GeoRL..3210706P">2005GeoRL..3210706P</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1029%2F2005GL022580">10.1029/2005GL022580</a></span>.</cite></span>

</li>

<li id="cite_note-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-20">^</a></b></span> <span class="reference-text"><cite id="CITEREFLee2009" class="citation journal cs1">Lee, D. S.; et al. (2009). <a rel="nofollow" class="external text" href="http://elib.dlr.de/59761/1/lee.pdf">"Aviation and global climate change in the 21st century"</a> <span class="cs1-format">(PDF)</span>. <i><a href="Atmos._Environ." class="mw-redirect" title="Atmos. Environ.">Atmos. Environ.</a></i> <b>43</b> (22): <span class="nowrap">3520–</span>3537. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2009AtmEn..43.3520L">2009AtmEn..43.3520L</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.atmosenv.2009.04.024">10.1016/j.atmosenv.2009.04.024</a>. <a href="PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7185790">7185790</a></span>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/32362760">32362760</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20160716195614/http://elib.dlr.de/59761/1/lee.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 16 July 2016.</cite></span>

</li>

<li id="cite_note-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-21">^</a></b></span> <span class="reference-text"><cite id="CITEREFMichael_Le_Page2019" class="citation news cs1">Michael Le Page (27 June 2019). <a rel="nofollow" class="external text" href="https://www.newscientist.com/article/2207886-it-turns-out-planes-are-even-worse-for-the-climate-than-we-thought/">"It turns out planes are even worse for the climate than we thought"</a>. <i>New Scientist</i><span class="reference-accessdate">. Retrieved <span class="nowrap">13 October</span> 2021</span>.</cite></span>

</li>

<li id="cite_note-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-22">^</a></b></span> <span class="reference-text"><cite id="CITEREFBockBurkhardt2019" class="citation journal cs1">Bock, Lisa; Burkhardt, Ulrike (2019). <a rel="nofollow" class="external text" href="https://acp.copernicus.org/articles/19/8163/2019/">"Contrail cirrus radiative forcing for future air traffic"</a>. <i>Atmospheric Chemistry and Physics</i>. <b>19</b> (12): 8163. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2019ACP....19.8163B">2019ACP....19.8163B</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.5194%2Facp-19-8163-2019">10.5194/acp-19-8163-2019</a></span>.</cite></span>

</li>

<li id="cite_note-IPCC_WGI_SPM-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-IPCC_WGI_SPM_23-0">^</a></b></span> <span class="reference-text">IPCC, 2021: <a rel="nofollow" class="external text" href="https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM.pdf">Summary for Policymakers</a>. In: <a rel="nofollow" class="external text" href="https://www.ipcc.ch/report/ar6/wg1/">Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change</a> [Masson-Delmotte, V., P. Zhai, A. Pirani, S. L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M. I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J. B. R. Matthews, T. K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 3–32, <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1017%2F9781009157896.001">10.1017/9781009157896.001</a>.</span>

</li>

<li id="cite_note-24"><span class="mw-cite-backlink"><b><a href="#cite_ref-24">^</a></b></span> <span class="reference-text"><cite id="CITEREFBernhardt,_J.Carleton,_A._M.2015" class="citation cs2">Bernhardt, J.; Carleton, A. M. (14 March 2015), <a rel="nofollow" class="external text" href="https://rmets.onlinelibrary.wiley.com/doi/epdf/10.1002/joc.4303">"The impacts of long-lived jet contrail 'outbreaks' on surface station diurnal temperature range"</a>, <i>Journal of International Climatology</i>, <b>35</b> (15): <span class="nowrap">4529–</span>4538, <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2015IJCli..35.4529B">2015IJCli..35.4529B</a>, <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fjoc.4303">10.1002/joc.4303</a>, <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:128789946">128789946</a></cite></span>

</li>

<li id="cite_note-25"><span class="mw-cite-backlink"><b><a href="#cite_ref-25">^</a></b></span> <span class="reference-text"><cite id="CITEREFStuber2006" class="citation journal cs1">Stuber, Nicola; et al. (15 June 2006). <a rel="nofollow" class="external text" href="https://www.nature.com/articles/nature04877">"The importance of the diurnal and annual cycle of air traffic for contrail radiative forcing"</a>. <i><a href="Nature_(journal)" title="Nature (journal)">Nature</a></i>. <b>441</b> (7095): <span class="nowrap">864–</span>7. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2006Natur.441..864S">2006Natur.441..864S</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2Fnature04877">10.1038/nature04877</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/16778887">16778887</a>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:4348401">4348401</a>.</cite></span>

</li>

<li id="cite_note-26"><span class="mw-cite-backlink"><b><a href="#cite_ref-26">^</a></b></span> <span class="reference-text"><cite id="CITEREFPerkins,_Sid.2002" class="citation cs2">Perkins, Sid. (11 May 2002), <a rel="nofollow" class="external text" href="https://www.sciencenews.org/article/septembers-science-shutdown-airlines-aided-contrail-studies">"September's Science: Shutdown of airlines aided contrail studies"</a>, <i>Science News</i>, Science News Online<span class="reference-accessdate">, retrieved <span class="nowrap">13 October</span> 2021</span></cite></span>

</li>

<li id="cite_note-Travis2002Aug-27"><span class="mw-cite-backlink">^ <a href="#cite_ref-Travis2002Aug_27-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Travis2002Aug_27-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><cite id="CITEREFTravis,_D._J.A._CarletonR._G._Lauritsen2002" class="citation journal cs1">Travis, D. J.; A. Carleton; R. G. Lauritsen (August 2002). <a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F418601a">"Contrails reduce daily temperature range"</a>. <i>Nature</i>. <b>418</b> (6898): 601. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2002Natur.418..601T">2002Natur.418..601T</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F418601a">10.1038/418601a</a></span>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/12167846">12167846</a>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:4425866">4425866</a>.</cite></span>

</li>

<li id="cite_note-28"><span class="mw-cite-backlink"><b><a href="#cite_ref-28">^</a></b></span> <span class="reference-text"><cite id="CITEREFTravisA._M._CarletonR._G._Lauritsen2004" class="citation journal cs1">Travis, D. J.; A. M. Carleton; R. G. Lauritsen (March 2004). <a rel="nofollow" class="external text" href="https://journals.ametsoc.org/view/journals/clim/17/5/1520-0442_2004_017_1123_rviudt_2.0.co_2.xml">"Regional Variations in U.S. Diurnal Temperature Range for the 11–14 September 2001 Aircraft Groundings: Evidence of Jet Contrail Influence on Climate"</a>. <i>J. Clim</i>. <b>17</b> (5): 1123. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2004JCli...17.1123T">2004JCli...17.1123T</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1175%2F1520-0442%282004%29017%3C1123%3ARVIUDT%3E2.0.CO%3B2">10.1175/1520-0442(2004)017<1123:RVIUDT>2.0.CO;2</a>.</cite></span>

</li>

<li id="cite_note-29"><span class="mw-cite-backlink"><b><a href="#cite_ref-29">^</a></b></span> <span class="reference-text"><cite class="citation cs2"><a rel="nofollow" class="external text" href="https://www.sciencedaily.com/releases/2015/06/150618122236.htm">"Jet contrails affect surface temperatures"</a>, <i><a href="Science_Daily" class="mw-redirect" title="Science Daily">Science Daily</a></i>, 18 June 2015<span class="reference-accessdate">, retrieved <span class="nowrap">13 October</span> 2021</span></cite></span>

</li>

<li id="cite_note-contrails-30"><span class="mw-cite-backlink"><b><a href="#cite_ref-contrails_30-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFTravisCarletonLauritsen2002" class="citation journal cs1">Travis, David J.; Carleton, Andrew M.; Lauritsen, Ryan G. (2002). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20060503192714/http://facstaff.uww.edu/travisd/pdf/jetcontrailsrecentresearch.pdf">"Contrails reduce daily temperature range"</a> <span class="cs1-format">(PDF)</span>. <i><a href="Nature_(journal)" title="Nature (journal)">Nature</a></i>. <b>418</b> (6898): 601. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2002Natur.418..601T">2002Natur.418..601T</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F418601a">10.1038/418601a</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/12167846">12167846</a>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:4425866">4425866</a>. Archived from <a rel="nofollow" class="external text" href="http://facstaff.uww.edu/travisd/pdf/jetcontrailsrecentresearch.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 3 May 2006.</cite></span>

</li>

<li id="cite_note-31"><span class="mw-cite-backlink"><b><a href="#cite_ref-31">^</a></b></span> <span class="reference-text"><cite id="CITEREFKalksteinBalling_Jr.2004" class="citation journal cs1">Kalkstein; Balling Jr. (2004). <a rel="nofollow" class="external text" href="http://www.int-res.com/abstracts/cr/v26/n1/p1-4/">"Impact of unusually clear weather on United States daily temperature range following 9/11/2001"</a>. <i>Climate Research</i>. <b>26</b>: 1. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2004ClRes..26....1K">2004ClRes..26....1K</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.3354%2Fcr026001">10.3354/cr026001</a></span>.</cite></span>

</li>

<li id="cite_note-32"><span class="mw-cite-backlink"><b><a href="#cite_ref-32">^</a></b></span> <span class="reference-text"><cite id="CITEREFHongYangMinnisHu2008" class="citation journal cs1">Hong, Gang; Yang, Ping; Minnis, Patrick; Hu, Yong X.; North, Gerald (2008). <a rel="nofollow" class="external text" href="https://doi.org/10.1029%2F2008GL036108">"Do contrails significantly reduce daily temperature range?"</a>. <i>Geophysical Research Letters</i>. <b>35</b> (23): L23815. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2008GeoRL..3523815H">2008GeoRL..3523815H</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1029%2F2008GL036108">10.1029/2008GL036108</a></span>.</cite></span>

</li>

<li id="cite_note-33"><span class="mw-cite-backlink"><b><a href="#cite_ref-33">^</a></b></span> <span class="reference-text"><cite id="CITEREFIrfan2011" class="citation web cs1">Irfan, Umair (7 July 2011). <a rel="nofollow" class="external text" href="http://www.scientificamerican.com/article/contrails-aviation-affects-climate/">"World War II Bomber Contrails Show How Aviation Affects Climate"</a>. <i>scientificamerican.com (ClimateWire)</i><span class="reference-accessdate">. Retrieved <span class="nowrap">13 October</span> 2021</span>.</cite></span>

</li>

<li id="cite_note-34"><span class="mw-cite-backlink"><b><a href="#cite_ref-34">^</a></b></span> <span class="reference-text"><cite id="CITEREFParry2011" class="citation web cs1">Parry, Wynne (7 July 2011). <a rel="nofollow" class="external text" href="http://www.livescience.com/14944-wwii-bombing-raids-contrails-weather-climate.html">"WWII Bombing Raids Altered English Weather"</a>. <i>livescience.com</i><span class="reference-accessdate">. Retrieved <span class="nowrap">13 October</span> 2021</span>.</cite></span>

</li>

<li id="cite_note-35"><span class="mw-cite-backlink"><b><a href="#cite_ref-35">^</a></b></span> <span class="reference-text"><cite id="CITEREFRyan2012" class="citation journal cs1">Ryan, A. C.; et al. (2012). <a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fjoc.2392">"World War II contrails: A case study of aviation-induced cloudiness"</a>. <i>International Journal of Climatology</i>. <b>32</b> (11): <span class="nowrap">1745–</span>1753. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2012IJCli..32.1745R">2012IJCli..32.1745R</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fjoc.2392">10.1002/joc.2392</a></span>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:129296874">129296874</a>.</cite></span>

</li>

<li id="cite_note-36"><span class="mw-cite-backlink"><b><a href="#cite_ref-36">^</a></b></span> <span class="reference-text"><cite id="CITEREFDigbyGillettMonahanCole2021" class="citation journal cs1">Digby, Ruth A. R.; Gillett, Nathan P.; Monahan, Adam H.; Cole, Jason N. S. (29 September 2021). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8667656">"An Observational Constraint on Aviation-Induced Cirrus From the COVID-19-Induced Flight Disruption"</a>. <i>Geophysical Research Letters</i>. <b>48</b> (20): e2021GL095882. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1029%2F2021GL095882">10.1029/2021GL095882</a></span>. <a href="PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8667656">8667656</a></span>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/34924638">34924638</a>.</cite></span>

</li>

<li id="cite_note-37"><span class="mw-cite-backlink"><b><a href="#cite_ref-37">^</a></b></span> <span class="reference-text"><cite id="CITEREFGettelmanChenBardeen2021" class="citation journal cs1">Gettelman, Andrew; Chen, Chieh-Chieh; Bardeen, Charles G. (18 June 2021). <a rel="nofollow" class="external text" href="https://acp.copernicus.org/articles/21/9405/2021/">"The climate impact of COVID-19-induced contrail changes"</a>. <i>Atmospheric Chemistry and Physics</i>. <b>21</b> (12): <span class="nowrap">9405–</span>9416. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.5194%2Facp-21-9405-2021">10.5194/acp-21-9405-2021</a></span>.</cite></span>

</li>

<li id="cite_note-38"><span class="mw-cite-backlink"><b><a href="#cite_ref-38">^</a></b></span> <span class="reference-text"><cite id="CITEREFZhuPennerGarnierBoucher2022" class="citation journal cs1">Zhu, Jialei; Penner, Joyce E.; Garnier, Anne; Boucher, Olivier; Gao, Meng; Song, Lei; Deng, Junjun; Liu, Cong-qiang; Fu, Pingqing (18 March 2022). <a rel="nofollow" class="external text" href="https://doi.org/10.1029%2F2021AV000546">"Decreased Aviation Leads to Increased Ice Crystal Number and a Positive Radiative Effect in Cirrus Clouds"</a>. <i>AGU Advances</i>. <b>3</b> (2): ee2020GL089788. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1029%2F2021AV000546">10.1029/2021AV000546</a></span>. <a href="Hdl_(identifier)" class="mw-redirect" title="Hdl (identifier)">hdl</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://hdl.handle.net/2027.42%2F172020">2027.42/172020</a></span>.</cite></span>

</li>

<li id="cite_note-39"><span class="mw-cite-backlink"><b><a href="#cite_ref-39">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.eurocontrol.int/article/unique-opportunity-accelerate-development">"A unique opportunity to accelerate development | EUROCONTROL"</a>. <i>www.eurocontrol.int</i>. 16 November 2020<span class="reference-accessdate">. Retrieved <span class="nowrap">10 May</span> 2024</span>.</cite></span>

</li>

<li id="cite_note-40"><span class="mw-cite-backlink"><b><a href="#cite_ref-40">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.eurocontrol.int/news/eurocontrol-launches-contrailnet-new-network-create-common-repository-contrail-observation">"EUROCONTROL launches ContrailNet - the new network to create a common repository of contrail observation data | EUROCONTROL"</a>. <i>www.eurocontrol.int</i>. 7 November 2023<span class="reference-accessdate">. Retrieved <span class="nowrap">12 May</span> 2024</span>.</cite></span>

</li>

<li id="cite_note-41"><span class="mw-cite-backlink"><b><a href="#cite_ref-41">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://contrails.org/">"Reviate - Contrail avoidance for the climate"</a>. <i>contrails.org</i><span class="reference-accessdate">. Retrieved <span class="nowrap">12 May</span> 2024</span>.</cite></span>

</li>

<li id="cite_note-42"><span class="mw-cite-backlink"><b><a href="#cite_ref-42">^</a></b></span> <span class="reference-text"><cite id="CITEREFAndrews2023" class="citation web cs1">Andrews, Siân (13 December 2023). <a rel="nofollow" class="external text" href="https://nats.aero/blog/2023/12/leading-the-way-in-contrail-avoidance/">"Leading the Way in Contrail Avoidance"</a>. <i>NATS Blog</i><span class="reference-accessdate">. Retrieved <span class="nowrap">12 May</span> 2024</span>.</cite></span>

</li>

<li id="cite_note-43"><span class="mw-cite-backlink"><b><a href="#cite_ref-43">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://sites.research.google/contrails/">"Project Contrails: Preventing Contrails with AI - Google Research"</a>. <i>Project Contrails: Preventing Contrails with AI - Google Research</i><span class="reference-accessdate">. Retrieved <span class="nowrap">12 May</span> 2024</span>.</cite></span>

</li>

<li id="cite_note-NS-44"><span class="mw-cite-backlink">^ <a href="#cite_ref-NS_44-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-NS_44-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><cite id="CITEREFMcKee2010" class="citation magazine cs1">McKee, Maggie (9 November 2010). <a rel="nofollow" class="external text" href="https://www.newscientist.com/article/dn19704-mystery-missile-likely-a-jet-contrail-says-expert.html">"Mystery 'missile' likely a jet contrail, says expert"</a>. <i><a href="New_Scientist" title="New Scientist">New Scientist</a></i>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20101110210639/http://www.newscientist.com/article/dn19704-mystery-missile-likely-a-jet-contrail-says-expert.html">Archived</a> from the original on 10 November 2010<span class="reference-accessdate">. Retrieved <span class="nowrap">10 November</span> 2010</span>.</cite></span>

</li>

<li id="cite_note-cont-45"><span class="mw-cite-backlink">^ <a href="#cite_ref-cont_45-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-cont_45-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><cite id="CITEREFWest2010" class="citation web cs1">West, Mick (10 November 2010). <a rel="nofollow" class="external text" href="http://contrailscience.com/a-problem-of-perspective-in-the-oc-new-years-eve-contrail/">"A Problem of Perspective – New Year's Eve Contrail"</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20101112192207/http://contrailscience.com/a-problem-of-perspective-in-the-oc-new-years-eve-contrail/">Archived</a> from the original on 12 November 2010<span class="reference-accessdate">. Retrieved <span class="nowrap">10 November</span> 2010</span>.</cite></span>

</li>

<li id="cite_note-46"><span class="mw-cite-backlink"><b><a href="#cite_ref-46">^</a></b></span> <span class="reference-text"><cite class="citation news cs1"><a rel="nofollow" class="external text" href="https://www.cbsnews.com/news/pentagon-cant-explain-missile-off-california/">"Pentagon Can't Explain "Missile" off California"</a>. <a href="CBS" title="CBS">CBS</a>. 9 November 2010. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20101110212004/http://www.cbsnews.com/stories/2010/11/09/national/main7037857.shtml">Archived</a> from the original on 10 November 2010<span class="reference-accessdate">. Retrieved <span class="nowrap">10 November</span> 2010</span>.</cite></span>

</li>

<li id="cite_note-47"><span class="mw-cite-backlink"><b><a href="#cite_ref-47">^</a></b></span> <span class="reference-text"><cite id="CITEREFPike2010" class="citation web cs1">Pike, John E. (November 2010). <a rel="nofollow" class="external text" href="http://www.globalsecurity.org/org/news/2010/101110-contrail.htm">"Mystery Missile Madness"</a>. GlobalSecurity.org<span class="reference-accessdate">. Retrieved <span class="nowrap">11 November</span> 2010</span>.</cite></span>

</li>

<li id="cite_note-48"><span class="mw-cite-backlink"><b><a href="#cite_ref-48">^</a></b></span> <span class="reference-text"><cite id="CITEREFBahneman2010" class="citation web cs1">Bahneman, Liem (9 November 2010). <a rel="nofollow" class="external text" href="http://blog.bahneman.com/content/it-was-us-airways-flight-808">"It was US Airways flight 808"</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20101113060703/http://blog.bahneman.com/content/it-was-us-airways-flight-808">Archived</a> from the original on 13 November 2010<span class="reference-accessdate">. Retrieved <span class="nowrap">10 November</span> 2010</span>.</cite></span>

</li>

<li id="cite_note-49"><span class="mw-cite-backlink"><b><a href="#cite_ref-49">^</a></b></span> <span class="reference-text"><cite class="citation news cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20120112232749/http://www.mercurynews.com/news/ci_16574898">"Pentagon: 'Mystery missile' was probably airplane"</a>. <a href="Mercury_News" class="mw-redirect" title="Mercury News">Mercury News</a>/<a href="Associated_Press" title="Associated Press">AP</a>. 10 November 2010. Archived from <a rel="nofollow" class="external text" href="http://www.mercurynews.com/news/ci_16574898">the original</a> on 12 January 2012<span class="reference-accessdate">. Retrieved <span class="nowrap">11 November</span> 2010</span>.</cite></span>

</li>

<li id="cite_note-50"><span class="mw-cite-backlink"><b><a href="#cite_ref-50">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20021016164705/http://epod.usra.edu/archive/epodviewer.php3?oid=110784">"Distrail on Earth Science Picture of the Day"</a>. <i>epod.usra.edu</i>. Archived from <a rel="nofollow" class="external text" href="http://epod.usra.edu/archive/epodviewer.php3?oid=110784">the original</a> on 16 October 2002<span class="reference-accessdate">. Retrieved <span class="nowrap">11 January</span> 2008</span>.</cite></span>

</li>

<li id="cite_note-51"><span class="mw-cite-backlink"><b><a href="#cite_ref-51">^</a></b></span> <span class="reference-text"><cite id="CITEREFCorfidiBrandli,_Hank1986" class="citation journal cs1">Corfidi, Stephen; Brandli, Hank (May 1986). <a rel="nofollow" class="external text" href="http://nwafiles.nwas.org/digest/papers/1986/Vol11-Issue2-May1986/Pg37-Corfidi.pdf">"GOES views aircraft distrails"</a> <span class="cs1-format">(PDF)</span>. <i>National Weather Digest</i>. <b>11</b>: <span class="nowrap">37–</span>39. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170421061015/http://nwafiles.nwas.org/digest/papers/1986/Vol11-Issue2-May1986/Pg37-Corfidi.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 21 April 2017<span class="reference-accessdate">. Retrieved <span class="nowrap">13 October</span> 2021</span>.</cite></span>

</li>

</ol></div></div>

<div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div>

/* start https://en.wikipedia.org/ */

.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .infobox .side-box{font-size:100%}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}

/* end https://en.wikipedia.org/ */

</style><style data-mw-deduplicate="TemplateStyles:r1237033735">

/* start https://en.wikipedia.org/ */

@media print{body.ns-0 .mw-parser-output .sistersitebox{display:none!important}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}

/* end https://en.wikipedia.org/ */

</style><div class="side-box side-box-right sistersitebox"><style data-mw-deduplicate="TemplateStyles:r1126788409">

/* start https://en.wikipedia.org/ */

.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}

/* end https://en.wikipedia.org/ */

</style>

<div class="side-box-text plainlist">Wikimedia Commons has media related to <span style="font-weight: bold; font-style: italic;"><a href="https://commons.wikimedia.org/wiki/Category:Contrails" class="extiw external" title="commons:Category:Contrails">Contrails</a></span>.</div></div>

</div>

<div class="side-box-text plainlist">Look up <i><b><a href="https://en.wiktionary.org/wiki/Special:Search/contrail" class="extiw external" title="wiktionary:Special:Search/contrail">contrail</a></b></i> in Wiktionary, the free dictionary.</div></div>

</div>

<ul><li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20070202122112/http://asd-www.larc.nasa.gov/GLOBE/">Contrail Education</a> (archived) | NASA</li>

<li><a rel="nofollow" class="external text" href="http://www.contrails.nl/index.htm">Contrails.nl: Contrails and AviationSmog</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110220031116/http://www.contrails.nl/index.htm">Archived</a> 20 February 2011 at the <a href="Wayback_Machine" title="Wayback Machine">Wayback Machine</a> | Galleys of contrails and aviation smog</li>

<li><a rel="nofollow" class="external text" href="http://contrailscience.com/">Contral Science</a> | Reference site for debunking weird stories about contrails</li>

<li><cite id="CITEREFDunning2007" class="citation web cs1"><a href="Brian_Dunning_(author)" title="Brian Dunning (author)">Dunning, Brian</a> (15 February 2007). <a rel="nofollow" class="external text" href="https://skeptoid.com/episodes/4027">"Skeptoid #27: Chemtrails: Real or Not?"</a>. <i><a href="Brian_Dunning_(author)#Skeptoid_podcasts" title="Brian Dunning (author)">Skeptoid</a></i>.</cite></li></ul>

/* start https://en.wikipedia.org/ */

.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}

/* end https://en.wikipedia.org/ */

</style><style data-mw-deduplicate="TemplateStyles:r1236075235">

/* start https://en.wikipedia.org/ */

.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}

/* end https://en.wikipedia.org/ */

</style></div><div role="navigation" class="navbox" aria-labelledby="Cirrus_cloud_(Ci)_types88" style="padding:3px"><table class="nowraplinks mw-collapsible uncollapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><style data-mw-deduplicate="TemplateStyles:r1239400231">

/* start https://en.wikipedia.org/ */

.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}

/* end https://en.wikipedia.org/ */

</style><div id="Cirrus_cloud_(Ci)_types88" style="font-size:114%;margin:0 4em"><a href="Cirrus_cloud" title="Cirrus cloud">Cirrus cloud (Ci)</a> <a href="List_of_cloud_types" title="List of cloud types">types</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Species</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Cirrus_castellanus_cloud" title="Cirrus castellanus cloud">Cirrus castellanus (Ci cas)</a></li>

<li><a href="Cirrus_fibratus" title="Cirrus fibratus">Cirrus fibratus (Ci fib)</a></li>

<li><a href="Cirrus_floccus" title="Cirrus floccus">Cirrus floccus (Ci flo)</a></li>

<li><a href="Cirrus_spissatus_cloud" title="Cirrus spissatus cloud">Cirrus spissatus (Ci spa)</a></li>

<li><a href="Cirrus_uncinus_cloud" title="Cirrus uncinus cloud">Cirrus uncinus (Ci unc)</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Varieties</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Cirrus_duplicatus" title="Cirrus duplicatus">Cirrus duplicatus (Ci du)</a></li>

<li><a href="Cirrus_intortus_cloud" title="Cirrus intortus cloud">Cirrus intortus (Ci in)</a></li>

<li><a href="Cirrus_radiatus" title="Cirrus radiatus">Cirrus radiatus (Ci ra)</a></li>

<li><a href="Cirrus_vertebratus" title="Cirrus vertebratus">Cirrus vertebratus (Ci ve)</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Variants</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">

</div></td></tr></tbody></table></div>

<div class="navbox-styles"></div><div role="navigation" class="navbox" aria-labelledby="Cloud_genera_and_selected_species,_supplementary_features,_and_other_airborne_hydrometeors_-_WMO_Latin_terminology_except_where_indicated292" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div id="Cloud_genera_and_selected_species,_supplementary_features,_and_other_airborne_hydrometeors_-_WMO_Latin_terminology_except_where_indicated292" style="font-size:114%;margin:0 4em"><a href="Cloud" title="Cloud">Cloud</a> <a href="List_of_cloud_types" title="List of cloud types">genera</a> and selected species, supplementary features, and other airborne <a href="Precipitation#Hydrometeor_definition" title="Precipitation">hydrometeors</a> - <a href="World_Meteorological_Organization" title="World Meteorological Organization">WMO</a> Latin terminology except where indicated</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%;text-align: center;"><a href="Mesospheric" class="mw-redirect" title="Mesospheric">Mesospheric</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Extreme-level80–85_km28" scope="row" class="navbox-group" style="width:10em">Extreme-level<br>80–85 km</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Noctilucent_(NLC)Polar_mesospheric_clouds68" scope="row" class="navbox-group" style="width:1%"><a href="Noctilucent_cloud" title="Noctilucent cloud">Noctilucent</a> (NLC)<br>Polar mesospheric clouds</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li>Noctilucent type I veils</li>

<li>Noctilucent type II bands</li>

<li>Noctilucent type III billows</li>

<li>Noctilucent type IV whirls</li></ul>

</div></td></tr></tbody></table><div></div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;text-align: center;"><a href="Stratospheric" class="mw-redirect" title="Stratospheric">Stratospheric</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Very_high-level15–30_km30" scope="row" class="navbox-group" style="width:10em">Very high-level<br>15–30 km</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Polar_stratospheric_cloud" title="Polar stratospheric cloud">Nacreous polar stratospheric clouds (PSC)</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li>Cirriform nacreous</li>

<li>Lenticular nacreous</li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Polar_stratospheric_cloud" title="Polar stratospheric cloud">Nitric acid and water<br>polar stratospheric clouds (PSC)</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li>No differentiated sub-types; tends to resemble cirrostratus</li></ul>

</div></td></tr></tbody></table><div></div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;text-align: center;"><a href="Tropospheric" class="mw-redirect" title="Tropospheric">Tropospheric</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:10em">High-level<br>3–18 km</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:15em"><a href="Cirrus_cloud" title="Cirrus cloud">Cirrus (Ci)</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Cloud_species" title="Cloud species">Species</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Cirrus_castellanus_cloud" title="Cirrus castellanus cloud">Cirrus castellanus (Ci cas)</a></li>

<li><a href="Cirrus_fibratus" title="Cirrus fibratus">Cirrus fibratus (Ci fib)</a></li>

<li><a href="Cirrus_floccus" title="Cirrus floccus">Cirrus floccus (Ci flo)</a></li>

<li><a href="Cirrus_spissatus_cloud" title="Cirrus spissatus cloud">Cirrus spissatus (Ci spa)</a></li>

<li><a href="Cirrus_uncinus_cloud" title="Cirrus uncinus cloud">Cirrus uncinus (Ci unc)</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Ci-only varieties</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Cirrus_intortus_cloud" title="Cirrus intortus cloud">Cirrus intortus (Ci in)</a></li>

<li><a href="Cirrus_vertebratus" title="Cirrus vertebratus">Cirrus vertebratus (Ci ve)</a></li></ul>

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:15em"><a href="Cirrocumulus_cloud" title="Cirrocumulus cloud">Cirrocumulus (Cc)</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Species25" scope="row" class="navbox-group" style="width:1%"><a href="Cloud_species" title="Cloud species">Species</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Cirrocumulus_castellanus" title="Cirrocumulus castellanus">Cirrocumulus castellanus (Cc cas)</a></li>

<li><a href="Cirrocumulus_floccus" title="Cirrocumulus floccus">Cirrocumulus floccus (Cc flo)</a></li>

<li><a href="Cirrocumulus_lenticularis" title="Cirrocumulus lenticularis">Cirrocumulus lenticularis (Cc len)</a></li>

<li><a href="Cirrocumulus_stratiformis" title="Cirrocumulus stratiformis">Cirrocumulus stratiformis (Cc str)</a></li></ul>

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:15em"><a href="Cirrostratus_cloud" title="Cirrostratus cloud">Cirrostratus (Cs)</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Species25" scope="row" class="navbox-group" style="width:1%"><a href="Cloud_species" title="Cloud species">Species</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Cirrostratus_fibratus" title="Cirrostratus fibratus">Cirrostratus fibratus (Cs fib)</a></li>

<li><a href="Cirrostratus_nebulosus" title="Cirrostratus nebulosus">Cirrostratus nebulosus (Cs neb)</a></li></ul>

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:15em">High-level-only<br>mutatus cloud</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em">

<ul><li>Mutatus non-height specific (see below)</li></ul>

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em">Medium-level<br>2–8 km</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:15em"><a href="Altocumulus_cloud" title="Altocumulus cloud">Altocumulus (Ac)</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Species25" scope="row" class="navbox-group" style="width:1%"><a href="Cloud_species" title="Cloud species">Species</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Altocumulus_castellanus_cloud" title="Altocumulus castellanus cloud">Altocumulus castellanus (Ac cas)</a></li>

<li><a href="Altocumulus_floccus" title="Altocumulus floccus">Altocumulus floccus (Ac flo)</a></li>

<li><a href="Altocumulus_lacunosus_cloud" title="Altocumulus lacunosus cloud">Altocumulus lacunosus (Ac la)</a></li>

<li><a href="Lenticular_cloud" title="Lenticular cloud">Altocumulus lenticularis (Ac len)</a></li>

<li><a href="Altocumulus_stratiformis" title="Altocumulus stratiformis">Altocumulus stratiformis (Ac str)</a></li>

<li><a href="Altocumulus_volutus" title="Altocumulus volutus">Altocumulus volutus (Ac vol)</a></li></ul>

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:15em"><a href="Altostratus_cloud" title="Altostratus cloud">Altostratus (As)</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Altostratus_undulatus_cloud" title="Altostratus undulatus cloud">Altostratus undulatus</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:15em"><a href="Nimbostratus_cloud" title="Nimbostratus cloud">Nimbostratus (Ns)</a><br> Multi-level</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Varieties9" scope="row" class="navbox-group" style="width:1%">Varieties</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Nimbostratus_virga" class="mw-redirect" title="Nimbostratus virga">Nimbostratus virga (Ns vir)</a></li></ul>

</div></td></tr></tbody></table><div></div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em">Low-level<br>0–2 km</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:15em"><a href="Cumulonimbus_cloud" title="Cumulonimbus cloud">Cumulonimbus (Cb)</a><br> Towering vertical</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Cloud_species" title="Cloud species">Species</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Cumulonimbus_calvus" title="Cumulonimbus calvus">Cumulonimbus calvus (Cb cal)</a></li>

<li><a href="Cumulonimbus_capillatus" title="Cumulonimbus capillatus">Cumulonimbus capillatus (Cb cap)</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Cb-only supplementary features</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Wall_cloud#Associated_features" title="Wall cloud">Cumulonimbus cauda ((cau)</a> Tail cloud)</li>

<li><a href="Cumulonimbus_incus" title="Cumulonimbus incus">Cumulonimbus incus (inc)</a></li>

<li><a href="Wall_cloud" title="Wall cloud">Cumulonimbus murus ((mur)</a> Wall cloud)</li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Cb-only accessories and other</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Cumulonimbus_flumen" class="mw-redirect" title="Cumulonimbus flumen">Cumulonimbus flumen ((Cb flu)</a> Beaver tail)</li>

<li><a href="Overshooting_top" title="Overshooting top">Overshooting top</a></li>

<li><a href="Hot_tower" title="Hot tower">Hot tower</a></li></ul>

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:15em"><a href="Cumulus_cloud" title="Cumulus cloud">Cumulus (Cu)</a><br>Variable vertical extent</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Cloud_species" title="Cloud species">Species</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Fractus_cloud" title="Fractus cloud">Fractus</a></li>

<li><a href="Cumulus_humilis_cloud" title="Cumulus humilis cloud">Cumulus humilis (Cu hum)</a></li>

<li><a href="Cumulus_mediocris_cloud" title="Cumulus mediocris cloud">Cumulus mediocris (Cu med)</a></li>

<li>(<a href="Cumulus_congestus_cloud" title="Cumulus congestus cloud">Cumulus congestus (Cu con)</a> (<a href="Cumulus_castellanus_cloud" title="Cumulus castellanus cloud">Cumulus castellanus (unofficial alternative name for Cu con))</a> (<a href="International_Civil_Aviation_Organization" title="International Civil Aviation Organization">ICAO</a> term for Cu con and "Cu cas" is Towering cumulus [Tcu]))</li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Other</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Horseshoe_cloud" title="Horseshoe cloud">Horseshoe</a></li>

<li><a href="Trade_wind_cumulus_cloud" title="Trade wind cumulus cloud">Trade wind cumulus</a></li></ul>

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:15em"><a href="Stratus_cloud" title="Stratus cloud">Stratus (St)</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Cloud_species" title="Cloud species">Species</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Fractus_cloud" title="Fractus cloud">Stratus fractus (St fra)</a></li>

<li><a href="Stratus_nebulosus" title="Stratus nebulosus">Stratus nebulosus (St neb)</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">St-only genitus cloud and other</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Stratus_silvagenitus" title="Stratus silvagenitus">Stratus silvagenitus (St sil)</a></li>

<li><a href="Fog" title="Fog">Fog</a> (Fg) Surface level</li></ul>

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:15em"><a href="Stratocumulus_cloud" title="Stratocumulus cloud">Stratocumulus (Sc)</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Species25" scope="row" class="navbox-group" style="width:1%"><a href="Cloud_species" title="Cloud species">Species</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Stratocumulus_castellanus_cloud" title="Stratocumulus castellanus cloud">Stratocumulus castellanus (Sc cas)</a></li>

<li><a href="Stratocumulus_floccus_cloud" title="Stratocumulus floccus cloud">Stratocumulus floccus (Sc flo)</a></li>

<li><a href="Stratocumulus_lenticularis" title="Stratocumulus lenticularis">Stratocumulus lenticularis (Sc len)</a></li>

<li><a href="Stratocumulus_stratiformis" class="mw-redirect" title="Stratocumulus stratiformis">Stratocumulus stratiformis (Sc str)</a></li>

<li><a href="Stratocumulus_Undulatus" class="mw-redirect" title="Stratocumulus Undulatus">Stratocumulus Undulatus</a></li>

<li><a href="Stratocumulus_volutus" title="Stratocumulus volutus">Stratocumulus volutus (Sc vol)</a></li></ul>

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:15em">Low-level-only<br>supplementary features</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Arcus_cloud" title="Arcus cloud">Arcus ((arc)</a> Shelf)</li>

<li><a href="Funnel_cloud" title="Funnel cloud">Tuba ((tub)</a> Funnel cloud)</li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:15em">Low-level-only<br><a href="Accessory_cloud" title="Accessory cloud">accessory cloud</a> and other</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Pileus_(meteorology)" title="Pileus (meteorology)">Pileus (pil)</a></li>

<li><a href="Cumulonimbus_velum" title="Cumulonimbus velum">Velum (vel)</a></li>

<li><a href="Scud_(cloud)" title="Scud (cloud)">Pannus (pan)</a></li>

<li>Other- <a href="Actinoform_cloud" title="Actinoform cloud">Actinoform cloud</a> (Stratocumulus)</li></ul>

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em">Non-height<br>specific</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:15em">Varieties</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Cirrus_duplicatus" title="Cirrus duplicatus">Duplicatus (du)</a></li>

<li><a href="Cirrocumulus_lacunosus" title="Cirrocumulus lacunosus">Lacunosus (la)</a></li>

<li><a href="Opacus_(cloud_variety)" title="Opacus (cloud variety)">Opacus (op)</a></li>

<li><a href="Perlucidus_(cloud_variety)" title="Perlucidus (cloud variety)">Perlucidus (pe)</a></li>

<li><a href="Cirrus_radiatus" title="Cirrus radiatus">Radiatus (ra)</a></li>

<li><a href="Translucidus_(cloud_variety)" title="Translucidus (cloud variety)">Translucidus (tr)</a></li>

<li><a href="Altostratus_undulatus_cloud" title="Altostratus undulatus cloud">Undulatus (un)</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:15em">Supplementary features</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Asperitas_(cloud)" title="Asperitas (cloud)">Asperitas (asp)</a></li>

<li><a href="Fallstreak_hole" title="Fallstreak hole">Cavum (cav)</a></li>

<li><a href="Kelvin%E2%80%93Helmholtz_instability" title="Kelvin–Helmholtz instability">Fluctus (flu)</a></li>

<li><a href="Mammatus_cloud" title="Mammatus cloud">Mamma (mam)</a></li>

<li><a href="Precipitation" title="Precipitation">Praecipitatio (pra)</a></li>

<li><a href="Virga" title="Virga">Virga (vir)</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:15em">Mother clouds <br> and human-made clouds</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em">

<ul><li>(Mother cloud)+genitus (e.g. cumulogenitus (cugen)</li>

<li>(Mother cloud)+mutatus (e.g. cumulomutatus (cumut)<br></li>

<li><a href="Homogenitus_(cloud)" class="mw-redirect" title="Homogenitus (cloud)">Homogenitus (hogen)</a></li>

<li>Homomutatus (homut)</li></ul>

</div></td></tr></tbody></table><div></div></td></tr></tbody></table><div></div></td></tr></tbody></table></div>

<div class="navbox-styles"></div><div role="navigation" class="navbox authority-control" aria-labelledby="Authority_control_databases_frameless&#124;text-top&#124;10px&#124;alt=Edit_this_at_Wikidata&#124;link=https&#58;//www.wikidata.org/wiki/Q207546#identifiers&#124;class=noprint&#124;Edit_this_at_Wikidata800" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div id="Authority_control_databases_frameless&#124;text-top&#124;10px&#124;alt=Edit_this_at_Wikidata&#124;link=https&#58;//www.wikidata.org/wiki/Q207546#identifiers&#124;class=noprint&#124;Edit_this_at_Wikidata800" style="font-size:114%;margin:0 4em">Authority control databases </div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">National</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"><ul><li><span class="uid"><a rel="nofollow" class="external text" href="https://d-nb.info/gnd/4474072-4">Germany</a></span></li><li><span class="uid"><a rel="nofollow" class="external text" href="https://id.loc.gov/authorities/sh85030764">United States</a></span></li><li><span class="uid"><a rel="nofollow" class="external text" href="https://www.nli.org.il/en/authorities/987007553041405171">Israel</a></span></li></ul></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Other</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"><ul><li><span class="uid"><a rel="nofollow" class="external text" href="https://catalog.archives.gov/id/10665617">NARA</a></span></li><li><span class="uid"><a rel="nofollow" class="external text" href="https://lux.collections.yale.edu/view/concept/9b766c34-ba09-4091-a035-cf9f92c74369">Yale LUX</a></span></li></ul></div></td></tr></tbody></table></div></div><div><div class="zim-footer">

This article is issued from <a class="external text" title="Last edited on 2025-07-27" href="https://en.wikipedia.org/wiki/?title=Contrail&oldid=1302794958">Wikipedia</a>. The text is available under <a class="external text" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en">Creative Commons Attribution-Share Alike 4.0</a> unless otherwise noted. Additional terms may apply for the media files.

</div>

</div></div>

</div>

</main>

</div>

</body></html>