Paper 1 · November 2023 · Climatology
The troposphere is heated mainly from below rather than directly by incoming solar radiation. What is the main reason temperature falls with increasing altitude within it?
AThe tropopause actively radiates additional heat downward into the upper troposphere, adding a second heat source above that would, if real, warm rather than cool the upper troposphere.
BThe surface absorbs most incoming solar radiation and re-radiates and conducts heat upward, so higher layers receive progressively less of that heat, and rising air also cools by adiabatic expansion.
CShort-wave insolation is absorbed almost entirely by the upper atmosphere before it reaches the surface.
DAir pressure increases steadily with height, which directly raises the air's temperature.
Explanation
Because the surface is the main heat source, layers further from it receive progressively less heat by conduction and re-radiation, and rising air additionally cools through adiabatic expansion as pressure falls with height.
Derived from ZIMSEC Advanced Level Geography 6037/1 Paper 1: Physical Component, November 2023 session, Q1