How does air temperature change in the ISA from MSL to approximately 10 000 meters in altitude?
Because the atmosphere is primarily heated from below, it is warmest at the surface. As a result, the temperature of the air usually decreases with height. This general change in temperature with altitude is known as the environmental lapse rate (ELR). The theoretical average ELR, defined by the International Standard Atmosphere (ISA), is 1.98°C per 1000 feet (0.65°C per 100 meters).
According to the ISA, the temperature at mean sea level (MSL) is +15°C. Using the ELR, we can calculate the temperature at 10 000 meters as follows:
10 000 m ÷ 100 m = 100 m
100 m x -0.65°C = -65°C
-65°C + 15°C = -50°C
Therefore, at an altitude of 10 000 meters, the expected temperature according to the ISA would be -50°C.
Your Notes (not visible to others)
This question has appeared on the real examination, you can find the related countries below.
-
Austro Control