Atmospheric Effects aka Heat Waves

Joined
Jan 2, 2009
Messages
6,673
Location
Alaska
Real Name
Dan
This topic comes up fairly frequently. Most people think it is only an issue when shooting across a hot surface. However it can occur at any temperature. The phenomenon is not caused by high temperatures but rather by temperature differences in the air. The overall temperature can be quite cold and thermal effects can still occur.

This morning while enjoying my morning coffee I noticed that there was an extreme amount of atmospheric distortion in our view of the valley/inlet. In the valley below( image no.2) it was 21F(-6C) and calm. At our house it was 29F(-2C) with 20-30mph wind. The temperature inversion was due to the warm "chinook" wind blowing down the mountain.

The white at bottom of frame in image no.2 is a frozen lake with a couple of feet of snow covering it. Also it was early morning and heavily overcast. So the distortion is certainly not due to heat rising from the surface. The difference in conditions caused a layer of turbulent air of variable temperature/density between the camera and the subject. That is the cause of the "heat wave" effect. Without the wind/turbulence a temperature inversion like this can cause distortion but it manifests itself as a shift in apparent position or stretching of the distant object rather than the wavy effect. That phenomenon is known as "fata morgana" as seen in image no.3.

D850(DX mode), 500mm PF, 1/1000s f8 ISO800, handheld, images received exactly the same minimal PP/crop in LR, only sharpening was during export to jpeg

1) Focused on spruce tree about 200 ft from camera.
p2308853548-5.jpg
Subscribe to see EXIF info for this image (if available)


2) Focused on the house about a mile distant and several hundred feet lower elevation.
p2308853562-5.jpg
Subscribe to see EXIF info for this image (if available)


3) Fata Morgana effect on distant mountains shot on a calm, extremely cold day.
p4101388415-6.jpg
Subscribe to see EXIF info for this image (if available)
 
Last edited:

Commodorefirst

Admin/Moderator
Administrator
Joined
May 1, 2005
Messages
23,573
Location
Missouri
And it can be particularly bad across open water, and a plowed field too. Great demonstration images.
 

F64

Joined
Dec 28, 2020
Messages
82
Location
Southwestern Ontario
Real Name
Greg
When we lived on Lake Erie, there were often inversions on the horizon that actually reflected images of lake freighters that were over the horizon - upside down in the air above the lake. I didn't have any telephotos in those days, so I was never able to get a good picture of the phenomenon.
It was a great location for lightning photos - and once I saw ball lightning - but of course, missed the shot.
 
Joined
Feb 20, 2011
Messages
3,868
Location
New Zealand
Normal refraction also means you can see beyond the horizon. If I remember right it's 14" of arc per kilometre the light bends, on average.
 

F64

Joined
Dec 28, 2020
Messages
82
Location
Southwestern Ontario
Real Name
Greg
Normal refraction also means you can see beyond the horizon. If I remember right it's 14" of arc per kilometre the light bends, on average.
Yes - but I couldn't explain how the ships would appear upside down unless there was an inversion that reflected the over the horizon image like a mirage on hot pavement.
 

F64

Joined
Dec 28, 2020
Messages
82
Location
Southwestern Ontario
Real Name
Greg
If they were so far away, how do you know they weren't upside down? :p
Ha! You got me there. They were right side up as they steamed west across Lake Erie in front of me until they disappeared over the horizon and then popped up in the air above the water upside down. And no, I don't drink LOL. We lived in Southwestern Ontario right across from the Enrico Fermi nuclear generating station.
 

Growltiger

Administrator
Administrator
Joined
Apr 26, 2008
Messages
13,443
Location
Up in the hills, Gloucestershire, UK
It's called a "superior mirage" when you get a ship floating in the sky. They can be the right way up or upside down. Scroll down to that heading:
https://en.wikipedia.org/wiki/Mirage

Here are two recent ones seen here in England in March this year:
1620029426490.png
Subscribe to see EXIF info for this image (if available)
1620029542823.png
Subscribe to see EXIF info for this image (if available)
 
Last edited:

kilofoxtrott

European Ambassador
Moderator
Joined
Dec 29, 2011
Messages
9,562
Location
Tettnang, Germany
Real Name
Klaus
Joined
Apr 28, 2010
Messages
1,960
Location
Utah
Real Name
Carl
Heat mirage is not only confined to surfaces. One day the local f 35 squadron was doing a flyover to honor the medical people who were becoming shell shocked with the Covid pandemic. They were about 1500 feet, and following a local freeway. My photos were O.K., but on further inspection, the bottoms of the fuselages looked "funny" (wavy) the heat mirage reached that high. Something to be aware of, with super-teles and hot weather.
 
Joined
May 5, 2005
Messages
24,790
Location
SW Virginia
Heat mirage is not only confined to surfaces. One day the local f 35 squadron was doing a flyover to honor the medical people who were becoming shell shocked with the Covid pandemic. They were about 1500 feet, and following a local freeway. My photos were O.K., but on further inspection, the bottoms of the fuselages looked "funny" (wavy) the heat mirage reached that high. Something to be aware of, with super-teles and hot weather.

Could that have been caused by the hot jet engines?
 
Joined
Apr 28, 2010
Messages
1,960
Location
Utah
Real Name
Carl
Could that have been caused by the hot jet engines?

I think it may be possible, but unlikely. I called a friend of mine who worked on F 4 Phantoms and F 100 aircraft in the Viet Nam Era, servicing them immediately after a flight, and he had never experienced that phenomenon, but said it might be possible with today's materials and construction.
For me, I'd say the airflow from the plane's passage would...for want of a better term..."wash away" any heat mirage from the fuselage. Afaik, the only aircraft that generate significant heat from their speed through the air are the SR 71 "Blackbirds" at their Mach ++ airspeeds.
 

Commodorefirst

Admin/Moderator
Administrator
Joined
May 1, 2005
Messages
23,573
Location
Missouri
I have had images ruined by aircraft engine heat produced by a plane affecting an image of a plane behind by several seconds or more. The heat trail can linger for many many seconds.

many modern jet aircraft have cooling lines for hydraulics and electronics mounted in weird areas and surfaces of wings and bodies for cooling purposes, or located in areas to avoid heat signatures to avoid infrared or heat radar signatures missile tracking.
 
Last edited:
Links on this page may be to our affiliates. Sales through affiliate links may benefit this site.
Nikon Cafe is a fan site and not associated with Nikon Corporation.
Forum post reactions by Twemoji: https://github.com/twitter/twemoji
Forum GIFs powered by GIPHY: https://giphy.com/
Copyright © Amin Forums, LLC
Top Bottom