troposfäärist

The troposphere is the lowest layer of Earth's atmosphere, extending from the Earth's surface up to an average altitude of about 7 to 15 kilometers. This is the layer where all weather phenomena occur, including clouds, rain, snow, and storms. The temperature in the troposphere generally decreases with increasing altitude, a phenomenon known as the environmental lapse rate. This decrease in temperature is primarily due to the fact that the troposphere is heated from below by the Earth's surface, which absorbs solar radiation.

The composition of the troposphere is predominantly nitrogen (about 78%) and oxygen (about 21%), with smaller amounts of argon, carbon dioxide, and trace gases. Water vapor is also a significant component, though its concentration varies greatly with location and season. The density of the air is highest at the surface and decreases rapidly with altitude. This is why most aircraft fly in the upper troposphere or lower stratosphere to avoid turbulence and find thinner air for more efficient flight.

The boundary between the troposphere and the next layer, the stratosphere, is called the tropopause. The tropopause is characterized by a reversal of the temperature trend; above this boundary, temperature begins to increase with altitude. The height of the tropopause varies, being higher at the equator and lower at the poles. This layer plays a crucial role in regulating Earth's climate and is essential for life as we know it.