What is the environmental lapse rate in a standard atmosphere?

The environmental lapse rate in a standard atmosphere is a crucial concept in meteorology, particularly for pilots. It refers to the rate at which air temperature decreases with an increase in altitude. In the standard atmosphere, the environmental lapse rate is typically considered to be approximately 2 degrees Celsius per 1,000 feet (or 6.5 degrees Celsius per kilometer). This means that for every 1,000 feet you ascend, the temperature is expected to drop by about 2 degrees Celsius.

Understanding the environmental lapse rate is essential for pilots because it helps in anticipating changes in weather conditions, performance calculations, and altitude planning. A lapse rate of 2 degrees per 1,000 feet provides a baseline for interpreting atmospheric conditions encountered during flight.

The other values listed do not align with the established standard for the environmental lapse rate. While there can be variations in actual atmospheric conditions depending on humidity, time of year, and geographic location, the standard figure remains an important reference for meteorological assessments in aviation.