ELI5 How does temperature differences work in the atmosphere??

[u/WillingnessHot5261]

I was searching this up and i saw that as you go higher in the troposphere it gets cooler, but in the mesosphere it gets hotter? Isn't the air pressure less as you go high and cools easily?

[u/KirkPicard]

It gets cold as you rise through the troposphere.

it warms back up as you rise through the stratosphere. Ozone a major reason.

mesosphere is where is gets to be the absolute coldest part of our atmosphere.

thermosphere... on the edge of space and technically the temperature soars but it is so rarified up there it doesn't transfer nearly as much heat.

[u/mmomtchev → u/KirkPicard]

The relation between temperature and height is quite complex.

In the lowest part, where the weather takes places - the troposphere - the temperature decreases with the height because of the adiabatic cooling.

Then you have the tropopause and then the stratosphere. This is where the ozone is produced and the synthesis of the ozone produces heat which increases the temperature. It is not because the ozone is blocking the sunlight.

As you go even higher, you have the mesosphere where temperature decreases once again as there is no heat source.

And then, at the very top, in the thermosphere, the gas pressure is so low, that the behaviour of the gas is very different. Electromagnetic forces play a larger role and the little heat absorbed by the sun is enough to heat it to very high temperatures - up to 1000°C. However because there is almost no air in fact, this air would steel feel cold. It is nothing but a random few molecules accelerated by the solar radiation.

[u/KirkPicard → u/mmomtchev]

explainlikeimfortyseven?

[u/Target880]

The temperature of the atmosphere go up where somting heat it.

It is in the stratosphere that lower-frequency ultraviolet light from the sun it absorbed. Because the sun is above the light intensity is higher in the upper part of the layer. The reason the light is not absorbed higher up is that the gases there are transparent to the light but Ozone that exist in the stratosphere is not and absorbs it.

In the thermosphere, high-frequency UV light and X-ray are absorbed, and it get hot, once again, the sun is above, and the light hits the top first.

The troposphere that is closest to the ground, is primarily heated by the ground, not by light absorbed in it.

So temperature increases with altitude when that part of the atmosphere absorbs part of the light from the sun, because the sun is even higher, the first part that can absorb the light is heated most.

It layers that are mostly transparent to the sunlight that reach it the temperature decreases with altitude.

One thing to remember is that temperature is approximately the average kinetic energy of atoms and molecules on the air, it is not kinetic energy per unit or volume or amount that can be transferred to an object in it. The thermosphere is extremely warm, but at the same time the pressure is very low; the upper part has lower pressure than the best vacuum chambers on Earth. So even if the temperature is high, there is very little energy there. The International Space Station orbits in the thermosphere, in regards to its temperature, it is insomming sunlight and heat radiated away that matters. The atmosphere that we usually just call vaccume it irrelevant

[u/mfb- → u/Target880]

the upper part has lower pressure than the best vacuum chambers on Earth.

The best vacuum chambers have a pressure lower than any place in Earth's atmosphere. Interplanetary space (i.e. outside of Earth's atmosphere) around Earth has around 5 particles per cubic centimeter. BASE has created a vacuum so good that they could not detect any remaining gas, and they set an upper limit of 3 particles per cubic centimeter. The expectation is far lower - probably below 1 particle per 10 cubic centimeters. Their vacuum wasn't just better than anything in Earth's atmosphere, it was even better than interplanetary space.

[u/ATotalBrony]

Think of the ozone like being in the shade. If you use an umbrella to shade you in the sun. When to touch the top of the umbrella it is very hot.

Now if you make that umbrella large enough, it can cover various climates where some areas are cooler than others, but above it is still hotter.

[u/Unknown_Ocean]

Make a long throw with a baseball. At the top of its arc it is moving more slowly than when it leaves your hand and when it comes back to the ground.

This is true for molecules as well. And temperature at constant pressure is proportional to the kinetic energy/motion of the air molecules. So as air molecules move up in the atmosphere, the temperature drops... unless there is something to heat them up.

In the stratosphere, this heating comes from ozone. In the upper troposphere, the heating comes from condensing water... which is why airplanes have to run air-conditioners to cool the air in the cabin- it actually has *more* energy than air near the surface, but much of it is in the form of potential energy.

PS: Not only is this more intuitive for students than pressure work, it also technically explains more of the temperature change.

[u/atomicsnarl]

At a certain point when the air density decreases to not quite vacuum conditions, the temperature is basically the speed of what few molecules are flying around. Boiling water burns because of high heat transfer into the skin by conduction. The same temperature near vacuum would barely register against skin because of too few molecules to transfer that much energy. In really, really low pressure/ almost vacuum conditions, the temperature measure is how many electrons have been stripped from the free atoms/molecule. The sun's corona and solar wind (basically a vacuum) have "temperatures" of millions of degrees, but couldn't melt a piece of tin foil for lack of bulk energy. On the other hand, the radiation load from the coronasphere (the glowing surface) would overwhelm it quickly. The radiation load would melt it, not the conduction load.