a quick one on air temp.

[whoopx]

hi guys!

need a little help with this: why is the temperature at higher altitudes lower, considering the fact that you are actually nearer to the sun? (ya, the interviewer actually said that!)
understand that the correct answer is actually pressure difference, and remember reading somewhere about the space between the particles and the energy needed to keep them together. Am i anywhere near?

Thanks, and appreciate all replies!

[Tinstaafl]

The sun's radiation enters the atmosphere as predominantly short wave radiation. Most of this passes through the atmosphere relatively easily.

It then strikes the Earth's surface where it gets absorbed. Absorbing this radiation energy causes the surface to warm.

The surface then transfers this energy into the atmosphere as long wave radiation ie heat. This is done through radiation & conduction this long wave radiation.

What all of the above means is that the atmosphere is heated from below, not above.

[Bullet Tooth Tony]

An example of what Tinstaafi has explained is when cloud covered nights are often milder than clear cloudless nights.

The conduction and subsequent convection process lags behind the actual sun position i.e. it takes time for the sun to heat the ground and then convect to atmosphere. This is why the warmest part of the day is normally mid afternoon and not at midday when the sun is at its highest. This means that the surface continues to convect warm air to atmosphere after the sun has set. With full cloud cover during the night, the warm convected air is kept in the lower levels of the atmosphere because the cloud cover acts as a shield. With little or no cloud cover, the milder air is free to dissapate through much greater depths.