Contrails 'breaking up' clouds

ki_cz

Member
I've been trying to find the scientific reason behind contrails 'breaking up' thin layers of cloud cover and so far haven't managed to find anything. It's something that I don't see too often, but attached is an example, I don't want to speculate regarding the cause, but have some ideas. If anybody can post some actual information about the cause of this it would be greatly appreciated:
 

Attachments

Trailblazer

Moderator
Staff member
They're called distrails.

http://contrailscience.com/contrail-to-distrail/

They can form in one of two ways: either the heat of the engine causes water droplets in relatively low clouds to evaporate, or by triggering glaciation (freezing) of supercooled droplets, which then fall out of the cloud. Your picture looks to me like the former type, but I could be wrong.

https://www.aviationweather.ws/080_Condensation_Trails.php


https://www.skybrary.aero/index.php/Distrail


http://www.spc.noaa.gov/coolimg/distrail/
 

Hama Neggs

Senior Member.
Content from external source There is some debate regarding the mechanism behind the formation of a distrail.




One possible explanation is that the engine exhaust gasses, emitted by an aircraft flying through a thin veil of high level cloud such as Cirrus, warm the air causing the ice crystals in the cloud to turn to vapour and disappear, creating a clear passage behind the aircraft.

An alternative explanation is that when an aircraft flies through a super cooled cloud, this cloud freezes due to the disturbing airflow created by the aircraft, as well as by the addition of plenty of freezing nuclei due to the aircraft's exhaust gases. Some of the particles act as the nuclei onto which the droplets can start freezing. As the ice-crystals form, they grow in size and fall below, this is sometimes observed as fall streak clouds below the actual distrait, or they evaporate instantaneously when entering the lower layers.

Would this mean that there are areas of atmosphere which are devoid of condensation nuclei?
 

Trailblazer

Moderator
Staff member
Would this mean that there are areas of atmosphere which are devoid of condensation nuclei?
Freezing nuclei aren't the same as condensation nuclei. There are condensation nuclei everywhere in the atmosphere, but not ice nuclei. That's why you get ice-supersaturated regions, where RHi is above 100#, which are where persistent contrails form.
 

Hama Neggs

Senior Member.
Freezing nuclei aren't the same as condensation nuclei. There are condensation nuclei everywhere in the atmosphere, but not ice nuclei. That's why you get ice-supersaturated regions, where RHi is above 100#, which are where persistent contrails form.
I'm not sure I fully understand that. Could you elaborate?
 

Spectrar Ghost

Senior Member.
Freezing nuclei need the right structure to act as seeds for ice crystals. CCN simply need a surface for water to condense into and a small enough size that their terminal velocity is low and they don't just fall out of the atmosphere.
 

Trailblazer

Moderator
Staff member
Freezing nuclei need the right structure to act as seeds for ice crystals. CCN simply need a surface for water to condense into and a small enough size that their terminal velocity is low and they don't just fall out of the atmosphere.
Yes, vapour will condense onto just about any particles in the air if the humidity is above 100% relative to water. But if the humidity is below 100% relative to water but above 100% relative to ice (usually about 60-65% relative to water at the altitudes we are talking about) then it will only form ice crystals if there are suitable freezing nuclei available.

In very simple terms, it's harder for ice crystals to form, because they have to form in a certain alignment (hexagonal crystals), whereas water droplets can form in any random configuration.

If there are such freezing nuclei present, you get cirrus clouds. If there aren't, you get areas that are supersaturated relative to ice, just waiting for some suitable nuclei, such as those produced by aircraft exhaust.
 

Hama Neggs

Senior Member.
If there are such freezing nuclei present, you get cirrus clouds. If there aren't, you get areas that are supersaturated relative to ice, just waiting for some suitable nuclei, such as those produced by aircraft exhaust.
OK, but what has to be present for natural cirrus clouds to form? Where does the initial nucleus come from?
 

Trailblazer

Moderator
Staff member
OK, but what has to be present for natural cirrus clouds to form? Where does the initial nucleus come from?
Mineral dust, for the most part. It seems to be not totally understood as yet.

http://www.cas.manchester.ac.uk/resactivities/cloudphysics/background/ice/

A recent study found that ice nuclei are mostly mineral dust and metallic particles. It's not clear from the abstract where the metallic particles come from, but I would assume human activity, and probably jet exhaust (which contains metal particles due to engine wear).

http://science.sciencemag.org/conte...4145?sid=3452d17d-c6da-4124-8363-a77b28dc9102
 
Thread starter Related Articles Forum Replies Date
Mick West Curved and Looped Contrails in SoCal [San Diego Delays] Skydentify - What is that Thing in the Sky? 1
Mick West Crazy Contrails from LAX Ground Stop Skydentify - What is that Thing in the Sky? 1
D Explained: Photo of 747 with Contrails Only on One Side [Fake, April Fool] Contrails and Chemtrails 21
Mick West Infrared Photos of Clouds and Contrails Images and Videos: Contrails, Skies, and Aviation 17
Mick West Moonlight Contrails Images and Videos: Contrails, Skies, and Aviation 1
Mick West YouTube adds Encyclopedia Britannica article on Contrails to "Chemtrail" Videos Contrails and Chemtrails 18
Mick West Aerodynamic Contrails at 27,000 to 31,000 feet near Sacramento Images and Videos: Contrails, Skies, and Aviation 2
Trailblazer Sharp boundary between contrails and clear sky Images and Videos: Contrails, Skies, and Aviation 1
Mick West Plane Flies in Front of Super Blue Blood Moon Eclipse Images and Videos: Contrails, Skies, and Aviation 1
Clouds Givemethewillies Contrail lobes or mamma? The importance of correct terminology Contrails and Chemtrails 0
cloudspotter How Changing Weather Conditions Make Contrails Show Up Contrails and Chemtrails 9
Trailspotter Contrail cross over Tasmania and spinning contrails over Victoria Images and Videos: Contrails, Skies, and Aviation 0
Mick West Explained: Manurewa NZ, 'Extra-terrestrial' Fireball Jumps Up [Contrail, Altitude change] Skydentify - What is that Thing in the Sky? 7
Mick West Halifax, NS: Regularly Spaced Gaps in Contrails [Ethiopian Flight 501] Skydentify - What is that Thing in the Sky? 47
Mick West Some Perspective on Perspective Foreshortening - Contrails and UFOs Skydentify - What is that Thing in the Sky? 1
Mick West Explained: Viral Video of 787 Leaving Thick Contrails with Forced Perspective Skydentify - What is that Thing in the Sky? 1
Mick West A Plane Flying Across the Face of the Sun, with Contrails [Virgin Flight 353] Skydentify - What is that Thing in the Sky? 7
TEEJ Contrails filmed from commercial flight over the Irish Sea - 6th May 2017 Skydentify - What is that Thing in the Sky? 2
E Can someone tell me what these are? [Grid pattern contrails] Skydentify - What is that Thing in the Sky? 7
P Can someone please explain these trails at sunset [Contrails] Skydentify - What is that Thing in the Sky? 13
Mick West There Are No New Clouds, Just New Latin Classifications Contrails and Chemtrails 2
MikeC BBC: Biofuels 'could limit jet contrails' Contrails and Chemtrails 10
Mick West Spiral Contrails viewed from the International Space Station Skydentify - What is that Thing in the Sky? 12
ki_cz Claim: Satellite imagery showing 'sheet' of contrails Contrails and Chemtrails 7
Mick West GOES-16 Satellite Images of Contrails Images and Videos: Contrails, Skies, and Aviation 0
Mick West Explained: Contrails Appear "Hot" in Thermal Imaging because the Sky Appears Very Cold Skydentify - What is that Thing in the Sky? 4
Mick West Explained: Chilean Navy "UFO" video - Aerodynamic Contrails, Flight IB6830 Skydentify - What is that Thing in the Sky? 186
Clouds Givemethewillies Why do inner contrails spread more than outer contrails? Contrails and Chemtrails 9
Mick West Contrails Hidden In 1950s and 1960s Family Photos Images and Videos: Contrails, Skies, and Aviation 2
Mick West Four Engines, Flying West over Sacramento Skydentify - What is that Thing in the Sky? 6
Clouds Givemethewillies Persistent Aerodynamic Contrails From Propellor Tips Contrails and Chemtrails 12
Mick West A Sunlit Contrail Viewed From the Side Images and Videos: Contrails, Skies, and Aviation 0
Mick West Close Up Videos of Contrails Forming And Evolving Images and Videos: Contrails, Skies, and Aviation 19
Mick West Some "Black" Shadowed Aerodynamic Contrails Images and Videos: Contrails, Skies, and Aviation 4
Mick West Relative Humidity at Flight Altitudes. Resources and Contrail prediction. Contrails and Chemtrails 11
Mick West What's the Highest Contrail You've Taken a Photo Of? Contrails and Chemtrails 8
Mick West P900 Plane and Contrails Photos and Video Images and Videos: Contrails, Skies, and Aviation 17
Mick West Persistent Aerodynamic Contrail Forming @28,500 on 787 Images and Videos: Contrails, Skies, and Aviation 0
steve holmes Problems with Identifying Contrails in FlightRadar24 Contrails and Chemtrails 57
Mick West Why Were There Contrails Today, But Not Yesterday? It's the Weather! Contrails and Chemtrails 21
Mick West How Do You Take Good Photos of High Altitude Planes and Contrails? Images and Videos: Contrails, Skies, and Aviation 2
Mick West Debunked: Irrefutable Film Footage Of Climate Engineering Aerosol Spraying [Aerodynamic Contrails] Contrails and Chemtrails 4
Mick West Contrails over Sting & Peter Gabriel Concert in Lake Tahoe Skydentify - What is that Thing in the Sky? 5
Mick West Giant Dark Persistent Aerodynamic Contrail Images and Videos: Contrails, Skies, and Aviation 6
Kaylene Contrails in USA vs. Austraila Contrails and Chemtrails 4
C Strange Flickering in Contrail Video Posted in Earlier Thread [Focussing artifacts] Contrails and Chemtrails 7
F Explained: Video of plane leaving "6 chemtrails, then 2" [Mixed Exhaust and Aerodynamic Contrails] Contrails and Chemtrails 6
Trailspotter Twinjet with asynchronously stopping contrails over Thuringia [MNG Airlines Airbus A300 TC-MCA] Skydentify - What is that Thing in the Sky? 3
Mick West Explained: Head Of The Army Admits to "Little Green Men" [Covert Russian Agents] Conspiracy Theories 7
ki_cz "The Chemistry in Contrails" - paper Contrails and Chemtrails 8
Related Articles


















































Related Articles

Top