Adiabatic Temperature Changes in the Atmosphere

Adiabatic temperature changes in the atmosphere refer to the temperature changes that occur in the air without any exchange of heat with the surroundings. These changes are primarily caused by the expansion and compression of the air as it rises and sinks in the atmosphere. Among the given options, option 'C' correctly identifies the main cause of adiabatic temperature changes.

Expansion and Compression of the Air

When air rises in the atmosphere, it experiences a decrease in atmospheric pressure. As the pressure decreases, the air expands. This expansion leads to a decrease in temperature, known as adiabatic cooling. On the other hand, when air sinks in the atmosphere, it experiences an increase in atmospheric pressure. The increased pressure compresses the air, causing an increase in temperature, known as adiabatic heating.

Adiabatic temperature changes occur due to the following reasons:

1. Expansion and Adiabatic Cooling: As air rises in the atmosphere, it moves into regions of lower pressure. The decrease in pressure causes the air to expand, and this expansion results in a decrease in temperature. The adiabatic cooling rate is approximately 1°C per 100 meters of vertical ascent. This process is known as dry adiabatic cooling, as it occurs when there is no condensation of water vapor.

2. Compression and Adiabatic Heating: When air sinks in the atmosphere, it moves into regions of higher pressure. The increased pressure compresses the air, leading to an increase in temperature. The adiabatic heating rate is also approximately 1°C per 100 meters of vertical descent. This process is called dry adiabatic heating.

Conclusion

In conclusion, adiabatic temperature changes in the atmosphere are primarily caused by the expansion and compression of the air as it rises and sinks. The decrease in pressure during ascent leads to adiabatic cooling, while the increase in pressure during descent results in adiabatic heating. These adiabatic temperature changes play a crucial role in weather phenomena such as cloud formation, precipitation, and the development of thunderstorms.