2 upvotes, 1 direct replies (showing 1)
View submission: Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science
Air at higher elevations is colder because it is at a lower pressure. When any mass of air drops in pressure, it gets cold. You can observe this by letting some air out of a car tire on a hot day and noting that the air comes out cold. Likewise when air is compressed, it heats up.
So places with higher elevation are colder simply because the air that moves there from lower elevations cools down in the process as it expands, and vice versa.
In addition there are local effects, such as the canyon trapping heat due to its shape.
Comment by sunburn_on_the_brain at 27/04/2023 at 15:52 UTC
1 upvotes, 0 direct replies
There's also the composition of the walls. The rock walls at Grand Canyon soak up the sun's heat all day long. I live in southern Arizona at the same elevation as Phantom Ranch and the climate is very close to a match, but the bottom of the Canyon is hotter. We may be topping 110º here, but Phantom Ranch is often recording close to 120º or higher. I'm used to intense heat, however, I've found that the heat down there is a different animal. You can feel the heat radiating off the rocks at 3 am down there. There's an area a bit north of Phantom Ranch on North Kaibab Trail called The Box. It's a narrow section with 500+ foot high rock walls. Rangers will warn hikers not to be in that area between 10 am and 4 pm in the summer because it's just an oven down there and the heat can be even more deadly. (A little video and description at https://www.nps.gov/media/video/view.htm?id=B01C9B26-6E27-41A0-866B-839174539320[1][2] )
1: https://www.nps.gov/media/video/view.htm?id=B01C9B26-6E27-41A0-866B-839174539320
2: https://www.nps.gov/media/video/view.htm?id=B01C9B26-6E27-41A0-866B-839174539320