ülaõhu

Ülaõhu, also known as "upper air," refers to the atmospheric layer above the troposphere, the lowest layer of Earth's atmosphere where weather phenomena occur. It is divided into three main layers: the stratosphere, the mesosphere, and the thermosphere. The stratosphere extends from about 10 to 50 kilometers above the Earth's surface and is characterized by increasing temperature with altitude due to the absorption of ultraviolet radiation by ozone. The mesosphere lies between 50 and 85 kilometers and is the coldest layer of the atmosphere, with temperatures dropping to as low as -90 degrees Celsius. The thermosphere begins at about 85 kilometers and extends to around 600 kilometers, where temperatures can rise to over 1,000 degrees Celsius due to the absorption of solar radiation. The upper air plays a crucial role in protecting the Earth from harmful solar radiation and in the dynamics of weather and climate.