Which layer of the atmosphere is closest to Earth's surface?

The troposphere is the layer of the atmosphere that is closest to Earth's surface. It extends from the surface up to about 8 to 15 kilometers (5 to 9 miles) high, depending on geographical location and weather conditions. This layer is crucial for life on Earth, as it contains the majority of the atmosphere's mass, including the air we breathe, and is where most of the weather events occur.

In the troposphere, temperature decreases with altitude, which plays an important role in atmospheric circulation and weather patterns. Because it contains all of the atmospheric components that we experience directly, such as clouds, rain, and wind, it is vital for understanding Earth's climate and weather systems.

The other layers, like the stratosphere, mesosphere, and thermosphere, lie above the troposphere and have distinct characteristics and functions, such as containing the ozone layer or being involved in temperature processes separate from weather phenomena.