- Observe how the density distribution of the atmosphere changes as gravity (gravitational acceleration) is varied.
- The total kinetic energy of the air particles is assumed to be constant.
- Gravity is assumed to act uniformly, and no gas particles escape the Earth.
Density distribution in the atmosphere
The atmospheric density distribution is characterized by a decrease in density with increasing altitude. This occurs because Earth’s gravity holds air near the surface. About 99% of the total atmospheric mass is concentrated within approximately 32 km of the surface, and half of it lies within about 6 km. In addition, density varies depending on temperature, pressure, and humidity. For example, cold high-pressure regions have higher air density, whereas low-pressure regions, where the surface is heated and air rises, have lower density.