In the mesosphere above the stratopause, the temperature drops sharply with the increase of height.It is about 80 kilometers away, reaching the lowest point.In the mesosphere, it is about 95 degrees below zero, which is the lowest temperature in the atmosphere.In the middle gas layer, the sea rises by one kilometer, with an average decrease of about 3 degrees Celsius.
The air in the mesosphere is very clean, and there is no atmospheric phenomenon except for the occasional noctilucent clouds.The composition of this cloud is still unknown.[1]
The temperature in the mesosphere ranges from about 50 km to 80 km. The temperature generally decreases upward until the top of the mesosphere. The temperature drops to about minus 95 0C or lower, which is also the lowest place in the vertical structure of the atmosphere. From the ground to the top of the mesosphere (Mesopause), except for water vapor and ozone, the composition of other gases in the atmosphere is almost unchanged, so the regions below the mesosphere,We call it Homogeneous Layer.
characteristic
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Since the temperature decreases with the rise of altitude, a stronger vertical atmospheric motion will occur in the mesosphere.However, because the average temperature decline rate of the mesosphere is smaller than that of the troposphere, although there are a few convective activities, they are relatively stable, and there are few high pressure and low pressure phenomena.Because the density of the atmosphere in the mesosphere is very low, the thermal structure of this layer is mainly the balance between the ultraviolet ray absorbed by oxygen molecules and the infrared ray emitted by carbon dioxide for heating and cooling.
Seasonal variation
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The remarkable phenomenon in the mesosphere is that the temperature in summer will be lower than that in winter.This is because in winter, the breaking of atmospheric gravity waves transports westward momentum in this layer, just as it exerts a westward drag force.In order to balance this drag force, the atmosphere must move toward the pole to obtain the eastward Coriolis force.This meridional movement from the summer polar region to the winter polar region causes the atmosphere in the summer polar region to rise, and adiabatic expansion and cooling;The multipolar atmosphere sinks and is heated by adiabatic compression.The influence of this circulation on temperature exceeds that of solar radiation heating, so the temperature at the top of the mesosphere is the hottest in summer polar regions with direct sunlight, and the hottest in winter polar regions without sunlight.[2]
