American Meteorological Society Certification (AMS) Practice

The troposphere is the layer of the atmosphere that is closest to Earth's surface, and it is where almost all weather events occur. This is due to the fact that the troposphere contains the majority of the atmosphere's mass, including water vapor, which is essential for cloud formation and precipitation. Because of its proximity to the Earth's surface, temperature decreases with altitude in this layer, which contributes to the vertical motion of air, creating wind patterns and weather systems.

The troposphere extends from the Earth's surface up to an altitude of about 8 to 15 kilometers, depending on geographical location and weather conditions. Higher altitudes within this layer see a mix of air currents that drive weather phenomena such as storms, rain, and other atmospheric interactions.

The other layers, such as the stratosphere, mesosphere, and thermosphere, are situated above the troposphere and are characterized by stable air conditions, a lack of significant weather events, and different thermal structures. For instance, the stratosphere contains the ozone layer which absorbs and scatters ultraviolet solar radiation, while the mesosphere and thermosphere experience temperature increases with altitude but lack the moisture and varying temperatures necessary for weather formation.