troposfääriä

Troposfääriä is the lowest layer of Earth's atmosphere. It extends from the Earth's surface up to an average height of about 12 kilometers. The thickness of the troposphere varies with latitude and season, being thinner at the poles and thicker at the equator. It is the densest layer of the atmosphere, containing approximately 75-80% of the atmosphere's total mass.

All weather phenomena, such as clouds, rain, snow, and storms, occur within the troposphere. This is because it contains most of the atmosphere's water vapor, which is essential for these processes. Temperature generally decreases with increasing altitude within the troposphere. This phenomenon is known as the lapse rate. The average rate of decrease is about 6.5 degrees Celsius per kilometer.

The boundary between the troposphere and the layer above it, the stratosphere, is called the tropopause. At the tropopause, the temperature stops decreasing and begins to increase with altitude. Commercial airplanes typically fly in the lower stratosphere to avoid the turbulent weather of the troposphere. The composition of the troposphere is primarily nitrogen (about 78%) and oxygen (about 21%), with smaller amounts of argon, carbon dioxide, and trace gases. Human activities, particularly the emission of greenhouse gases, significantly impact the composition and temperature of the troposphere, leading to climate change.