What is meant by the lapse rate?

The lapse rate refers specifically to the rate at which temperature decreases with an increase in altitude in the atmosphere. As you ascend through the atmosphere, the air becomes less dense and generally cooler. This decrease in temperature with height is a fundamental concept in atmospheric science, as it affects weather patterns, air density, and the behavior of aircraft.

The lapse rate is typically measured in degrees Celsius per kilometer (°C/km), indicating how many degrees the temperature drops for each kilometer of altitude gained. Understanding this concept is crucial for meteorology, aviation, and environmental science, as it influences various phenomena, such as cloud formation and the behavior of thermals.

While pressure also decreases with altitude, the lapse rate specifically addresses temperature changes rather than pressure changes. Options discussing pressure or wind do not pertain to the specific concept of lapse rate, reinforcing the focus on temperature variation with altitude as the defining characteristic.