What is the environmental lapse rate and how is it determined?

The environmental lapse rate is the rate at which air temperature decreases with an increase in altitude in the Earth's atmosphere, typically averaging about 6.5°C per kilometer (or 1,000 meters) in the troposphere. It is determined through observational data collected from weather balloons, satellites, and ground-based measurements, which track temperature changes at various heights. Variations in the lapse rate can occur due to local weather conditions, humidity, and geographic factors. Understanding the environmental lapse rate is crucial for meteorology, aviation, and climate studies.