What is lapse rate?

Lapse rate refers to the rate at which atmospheric temperature decreases with an increase in altitude. This is a fundamental concept in meteorology that describes how temperatures typically decrease as you move from the Earth's surface upward into the atmosphere.

In the troposphere, which is the lowest layer of the atmosphere, temperatures generally decrease with altitude due to the decreasing pressure and density of the air. This cooling occurs because the Earth's surface absorbs solar radiation and is warmed, and as you ascend, you're moving away from that heat source.

Understanding lapse rate is essential for predicting weather patterns, cloud formation, and stability of the atmosphere. For example, when the temperature drops with altitude at a specific rate, it can influence whether air remains stable or becomes unstable, which affects weather phenomena such as thunderstorms.

The other options describe scenarios that do not capture the typical behavior of temperature with respect to altitude. Option A describes an increase in temperature with decreasing altitude, which would indicate a temperature inversion, a less common scenario. Option C, indicating constant temperature, doesn't align with the variability observed in the atmosphere. Finally, option D, which suggests variable temperature based on humidity, does not inherently address the relationship of altitude to temperature changes as described by the lapse rate.