Understanding Weather: A Comprehensive Guide

Chapter 2: The Structure of the Atmosphere

The atmosphere is composed of multiple layers, each playing a crucial role in weather formation. The troposphere, the lowest layer, extends from the Earth's surface up to about 12 kilometers (7.5 miles) and contains most of the atmosphere's mass. All weather phenomena occur in the troposphere, where temperature decreases with altitude. The troposphere is also where clouds form and where the Earth's surface influences weather through heating and cooling.

Above the troposphere lies the stratosphere, which extends from about 12 to 50 kilometers (7.5 to 31 miles) above the Earth's surface. The stratosphere contains the ozone layer, which absorbs and scatters ultraviolet solar radiation, protecting living organisms from harmful UV rays. Unlike the troposphere, the temperature in the stratosphere increases with altitude due to the absorption of radiation by ozone. This layer is crucial for shielding the planet from excessive solar radiation.

Higher still are the mesosphere, thermosphere, and exosphere. The mesosphere, extending from 50 to 85 kilometers (31 to 53 miles) above the Earth, is where meteors burn up upon entering the Earth's atmosphere. The thermosphere, ranging from 85 to 600 kilometers (53 to 373 miles), contains the ionosphere, which is important for radio communication. The outermost layer, the exosphere, transitions into space and contains very sparse hydrogen and helium. Each layer plays a specific role in protecting the Earth and supporting weather and climate processes.