What is the term for the average rate at which temperature decreases with an increase in altitude?

The term for the average rate at which temperature decreases with an increase in altitude is known as the lapse rate. This concept is critical in meteorology and atmospheric sciences, as it explains how temperature changes within the atmosphere as one ascends into higher elevations.

The lapse rate is typically measured in degrees Celsius per kilometer and is essential for understanding various atmospheric phenomena, including weather patterns and the behavior of air masses. Generally, the average lapse rate in the troposphere—where weather occurs—is approximately 6.5 degrees Celsius per kilometer.

This concept also plays a significant role in aviation, as pilots must consider the lapse rate when planning for altitude changes and understanding how temperature variations can affect aircraft performance, including lift and engine efficiency.

The other terms do not accurately define this specific atmospheric phenomenon. Temperature gradient refers to any change in temperature over distance but does not specifically indicate a decrease with altitude. Altitude adjustment typically refers to the process of changing altitude, while thermal balance is a broader term related to the equilibrium between incoming and outgoing thermal energy in a system, rather than specifically relating to altitude and temperature.