When you climb a high mountain like Ras Dejen in Ethiopia or the Kilimanjaro in Tanzania you will realize that the temperature is much lower there than on sea level. My question is: Is the lower temperature the result of the lower air pressure at higher altitudes or does the solid ground on the top of the mountain also receive less heat than the ground on sea level?
I always thought it is much colder at higher altitudes because there is much less solid mass there than at sea level. The sun's heat hardly warms the air as it passes through on the way to the ground. In other words, the sun's heat acts almost the same as the sun's light — it passes through the air almost as though the air wasn't there. What heats up much more than the atmosphere is the solid ground and the oceans. This means that almost all of the sun's heat goes into warming up the oceans and the land it hits. As the oceans and ground warm up, they warm the air next to them, and this air warms the air a little higher up and so on. But at the high altitudes of high mountains there is much less solid mass to heat up the air above it and therefore it is much colder.
Yup. A lot of the energy emitted by the sun is light. Yeah that's pretty much right as far as I can remember. I think convection takes over from here. Cooler, more dense air falls and displaces the less dense warm air, the cool air itself warms up, rises etc etc. Convection drives pretty much the whole climate You've lost me here. Mountains are as solid as ground at low altitudes. If I remember my first year notes (if) then it's the air pressure. There's less molecules per unit of volume, so even if these are given the same amount of energy from the ground than those at lower altitudes, the overall amount of energy, and thus temperature will be lower.
That makes sense. Same reason why the vaccuum of space wouldn't freeze you, even though its temperature is something like -250C. There's just not enough matter there to take the heat away from your body.
You will more readily get a sunburn on the top of a mountain. However, as air rises and becomes less dense, it also gets cooler. There is less air at high altitude to keep the heat in, so it escapes faster.
Insolation at the top of a mountain is considerably higher than it is at sea level. By the time sunlight reaches sealevel, the intensity of the solar radiation has been reduced by 45% due to absorption and reflection by the atmosphere and clouds, most of that by the lower atmosphere. So, why are mountaintops colder if they receive more solar energy? The answer is two-fold. First and foremost, the air is colder. Google "dry adiabatic lapse rate" for an explanation why. Secondly, while mountaintops receive more radiative heating, the flip side is also true: Mountaintops are subject to greater radiative cooling. The thin, clear air does little to hinder radiative cooling at night. This is why temperatures drop drastically at nightfall at altitude.
This is true but there is much less solid matter at high altitudes to transfer heat to the air directly above it. And because of the large distance from the ground, the solid mass at low altitudes does not transfer enough heat by conduction to the solid mass at high altitudes.
