The dry adiabatic lapse rate is the reason. Its 2°C per 1,000ft or 3.5°F. If the plane is cruising at 30,000ft that’s a temperature difference of 105°F from the plane to the ground.
Did some flying for awhile, gets cold up there.
How can an airplane hit -47°c (-52°f) temperatures while flying over Southern Florida?
Submitted 13 hours ago by JoMiran@lemmy.ml to [deleted]
Comments
tux7350@lemmy.world 4 hours ago
hildegarde@lemmy.blahaj.zone 4 hours ago
Its because the atmosphere is heated by the ground, not the sun.
Air is transparent. Sunlight will go right through it without transferring much heat at all. Instead the sunlight keeps going until it hits the earth.
The ground or water absorbs the heat from the sun, which in turn heats the ground, which heats the air just above it, which then rises and mixes with the colder air around it.
The heated air can only rise so far, so most of that heat stays near the ground, hence the temperature gradient between the surface and airplane cruising altitudes.
remon@ani.social 13 hours ago
Because that’s about how cold the air is at cruising altitude.
Skyrmir@lemmy.world 13 hours ago
While on the same machine, the turbine blades that melt at 1250 degrees operate at 1500 degrees.
It’s all magic
glups@piefed.social 11 hours ago
As a professional aircraft mechanic, I can confirm. It’s all magic
Skullgrid@lemmy.world 7 hours ago
wat?
Skyrmir@lemmy.world 3 hours ago
Turbine blades are pure aluminum, which melts at 1220 degrees. They operate inside the compression chamber of the turbine to move gases that are around 1500 degrees. There’s a whole art to making them single crystals and optimizing flow rates so they don’t melt, or explode, or melt and explode. And a lot of work goes into making sure when they do melt and explode, they don’t turn into supersonic bullets. Just barely though, because armor is heavy.
YurkshireLad@lemmy.ca 12 hours ago
If you’re talking about the Learjet that crashed (RIP), I think it was cruising around 37-41k feet. I don’t know the scientific reason for why it’s so cold up there.
cattywampas@lemmy.world 12 hours ago
The ground is opaque and dense so sunlight heats it effectively and it holds onto that heat well. Air is transparent and not very dense so it doesn’t heat well nor does it hold that heat.
Warm places are warm near the ground, but as you gain altitude it becomes cold quickly no matter where you are.
slazer2au@lemmy.world 13 hours ago
Because altitude. Much like how Mt Kilimanjaro has snow on it despite being close to the equator.
JoMiran@lemmy.ml 13 hours ago
Obviously I figured it’d be much colder, but I’ve been in -55°f wind chills and it took me being at 8000+ feet elevation, in a northern latitude, in the peak of a record setting winter, for us to hit that. So, yeah I expected freezing temps up there, but -52.6°f is making my brain hurt. It’s just so crazy that I figured it had to include some other weather phenomenon, not just altitude.
Shadow@lemmy.ca 12 hours ago
Every 1000ft you go up, the temperature drops by about 2c
shalafi@lemmy.world 4 hours ago
I was once on a fancy airliner that had readouts on the seat backs. One thing you could see was temperature. I believe it was -175F or so. This was also over Florida BTW. Only reason I know about this!
corsicanguppy@lemmy.ca 7 hours ago
What do you figure the wind chill of a few hundred mph may be?