What Is Atmospheric Circulation?

Atmospheric circulation generally refers to a large-scale atmospheric operation phenomenon with a world scale. It includes both average and transient phenomena. Its horizontal scale is more than thousands of kilometers, its vertical scale is more than 10 km, and its time scale is more than several days. It is also a state of large-scale movement of the atmosphere. Atmospheric movement of a large area (such as Eurasia, hemisphere, global) and a certain atmospheric level (such as the troposphere, stratosphere, middle layer, the entire atmosphere) over a long period (such as month, season, year, and many years) The average state of the atmosphere or the change of the atmospheric movement during a certain period (such as a week or the rainy season) can be called the atmospheric circulation.

There are three reasons for the formation of atmospheric circulation: one is solar radiation, which is the source of energy for the movement of the atmosphere on the earth.

Viewed from the global average zonal circulation, in the troposphere, the most basic feature is that the atmosphere generally orbits the earth along the latitude circle, and the east wind prevails in low latitudes, known as the east wind belt, also known as the north wind of the trade wind belt. For the northeast trade wind, the southern hemisphere is the southeast trade wind. Westerly winds prevail in mid-latitude regions, known as westerly belts. It spans a latitude wider than the east wind. Westerly strength increases with latitude. The maximum wind appears near 200 hPa over 30 ° -40 °, which is called the planet westerly jet. Near the polar regions, there is a shallow and weak east wind in the lower layer, called

Latitude circulation is also known as planetary wind system or barotropic wind belt. The wind belt and surge on the earth are driven by three convective circulations (three-circle circulation): Hadley circulation (low latitude)

Atmospheric circulation diagram

The state of large-scale movement of the atmosphere. Atmospheric movement of a large area (such as Eurasia, hemisphere, global) and a certain atmospheric level (such as the troposphere, stratosphere, middle layer, the entire atmosphere) over a long period (such as month, season, year, and many years) The average state of the atmosphere or the change of the atmospheric movement during a certain period (such as a week or the rainy season) can be called the atmospheric circulation.

Atmospheric circulation is an important mechanism to complete the transfer and balance of angular momentum, heat, and water in the earth-atmosphere system, as well as the mutual conversion between various energies. It is also an important result of the transfer, balance, and conversion of these physical quantities. Therefore, studying the characteristics of the atmospheric circulation and its formation, maintenance, change, and role, and mastering its evolution laws, will not only be an important and important part of human understanding of nature, but will also help improve and increase the accuracy of weather forecasting. It is conducive to exploring global climate change and using climate resources more effectively. Atmospheric circulation usually includes three parts: average zonal circulation, average horizontal circulation and average radial circulation. ^[2]