Final answer:
The temperature at 15,000 feet ASL in the ICAO standard atmosphere would be -15°C, calculated by applying the standard lapse rate of 2°C decrease per 1,000 feet up to the level of the tropopause.
Step-by-step explanation:
In the ICAO standard atmosphere, the temperature at an altitude of 15,000 feet above sea level (ASL) can be determined by applying the standard lapse rate. The standard lapse rate dictates that temperature decreases with an increase in altitude at a rate of approximately 2°C per 1,000 feet up to the altitude of the tropopause, which is around 36,000 feet ASL. The temperature at sea level is usually taken as 15°C (or 59°F). Therefore, at 15,000 feet, the temperature would be reduced by 2°C for every 1,000 feet, resulting in a decrease of 30°C from the sea level temperature. Thus:
- Temperature at sea level: 15°C
- Temperature decrease by 15,000 feet: 15 × 2 = 30°C
- Temperature at 15,000 feet ASL: 15°C - 30°C = -15°C