Why are the coldest temperatures at the lowest 50 km height from the surface of the Earth, occur generally at tropical tropopause?
The coldest temperatures at the lowest 50 km height from the surface of the Earth generally occur at the tropical tropopause due to a number of atmospheric factors.
To understand this, let's break it down step by step:
1. Start with the concept of the troposphere: The troposphere is the lowest layer of the Earth's atmosphere where weather occurs. It is characterized by a decrease in temperature with increasing altitude.
2. The tropopause: The tropopause is the boundary between the troposphere and the layer above called the stratosphere. It acts as a transitional layer where the temperature becomes more stable and starts increasing with altitude.
3. Importance of the tropical tropopause: The tropical tropopause is particularly significant because it is characterized by a very sharp temperature gradient, meaning that the temperature changes rapidly over a short vertical distance. This steep temperature gradient is mainly due to the presence of atmospheric phenomena such as strong convective activity and the formation of deep cumulonimbus clouds in the tropics.
4. Role of convective activity: In the tropics, the sun's energy heats the surface of the Earth, causing warm air near the surface to rise rapidly. This upward motion of air is known as convection. As the warm air rises, it expands and cools, leading to the formation of towering cumulonimbus clouds. These clouds have a significant impact on the temperature gradient at the tropical tropopause.
5. Cold temperatures at the tropopause: Due to the presence of convective activity and deep cumulonimbus clouds, the temperature decreases rapidly with increasing altitude in the lower portion of the tropical tropopause. This results in extremely cold temperatures at this altitude range.
In summary, the coldest temperatures at the lowest 50 km height from the surface of the Earth generally occur at the tropical tropopause due to the combination of strong convective activity, deep cumulonimbus clouds, and the resulting steep temperature gradient.