Stratosfera

Stratosfera is the second major layer of Earth's atmosphere, lying above the troposphere and below the mesosphere. It extends roughly from about 10 to 50 kilometers above the Earth's surface, with boundaries that vary by latitude and season. The stratosphere is notable for a temperature profile that increases with altitude, unlike the troposphere where temperature generally falls with height. This temperature inversion is caused by the absorption of ultraviolet radiation by ozone in the stratosphere, which warms the surrounding air.

A central feature of the stratosfera is the ozone layer, concentrated mainly in the 15–35 kilometer range. Ozone is formed when ultraviolet radiation splits molecular oxygen and the resulting atoms combine with O2 to form O3. Ozone is also destroyed by chemical reactions involving halogen species released from human-made compounds, leading to seasonal ozone depletion in some regions, most prominently over Antarctica. The depletion manifests as the ozone hole during certain months.

The stratosfera is relatively stable and exhibits limited vertical mixing compared with the troposphere, which reduces weather-related processes in this layer. Large-scale circulation, such as the Brewer–Dobson circulation, transports air from the tropics toward higher latitudes, while the quasi-biennial oscillation modulates winds in the equatorial stratosphere. In winter, polar stratospheric clouds can form in the polar regions and influence ozone chemistry when sunlight returns in spring.

Human activity and policy have significantly affected stratospheric chemistry. Since the 1980s, international agreements like the Montreal Protocol have reduced ozone-depleting substances, contributing to gradual signs of recovery in some areas. The stratosfera also serves as a site for scientific research, high-altitude flights, and balloon-borne instrumentation, occurring above much of the weather and providing insights into atmospheric dynamics and climate.