Tropospheric Distribution and Temperature Change _ Introduction to Tropospheric Physical Geography

Troposphere is the layer of the earth's atmosphere near the ground, and it is also the highest density layer in the earth's atmosphere. Dear friends, where is the troposphere in the atmosphere? Let me share information about the troposphere with you. Let's take a look together ~

Tropospheric distribution

The atmosphere is a whole composed of multiple layers of atmosphere. According to the change of temperature and height, it can be divided into troposphere, stratosphere, mesosphere, warm layer and exosphere from bottom to top. Among them, the troposphere is the closest layer to our life, where wind, rain, thunder and electricity all occur. The average thickness of the troposphere is about 12km. Although it is relatively thin, its weight accounts for about 80% of the total atmosphere. The troposphere is also the most active layer in the atmosphere. In warm places, air will rise, in cold places, air will fall, and cold and warm air will form convection, which is why people call it troposphere.

Differences in the troposphere

Although the atmosphere in the lower troposphere will rub against the surface, the air in the upper troposphere is not affected by this friction. So the weather phenomena in the upper and lower troposphere will be different. According to this phenomenon, the troposphere will be divided into three layers. The place from 0 m to 100 m above sea level is the grounding layer, from 100 m to 1 km is the Ekman layer, and from 1 km to the tropopause is called the free atmosphere. The ground layer will be subjected to greater friction with the ground, so its atmospheric movement and surge are very irregular and active. The Ackerman layer will be moved by three forces: Coriolis force, barometric tilt force and friction with the ground. As for the free atmosphere, it is not affected by ground friction, and the atmosphere is in a state of free movement.

In the upper part of the free atmosphere, that is, the upper part of the troposphere, there will be a jet flow. Its height is about 1 1 km from the ground, which is the place with the highest wind speed. For example, the westerly belt flowing over Japan is also located near the height of 1 1 km above the ground, with the highest wind speed. Although jet is one of the largest horizontal atmospheric movements in the troposphere, it is also a large-scale vertical atmospheric movement. Another example is atmospheric circulation, such as Hadley circulation, where hot air rises in the tropics and falls in the subtropical high. In this way, horizontal and vertical atmospheric movements constantly appear in the troposphere, and the free atmosphere is the prosperous layer of this atmospheric movement.

Tropospheric characteristics

Inverse temperature increase

In the troposphere, the temperature decreases with the elevation, with an average increase of 100 m, and the temperature decreases by about 0.65℃. The reason why the temperature decreases with the increase of altitude is that the main heat source of troposphere atmosphere is ground long-wave radiation. The higher off the ground, the less heated and the lower the temperature. However, under certain conditions, the temperature in the troposphere will also increase with the increase of height, which is the so-called "inversion phenomenon". Due to the great influence of the surface, the horizontal distribution of meteorological elements (temperature, humidity, etc.). ) uneven. The regular vertical movement of air and the irregular turbulence are quite intense. The water vapor, dust and heat in the upper and lower layers are exchanged and mixed. Because more than 90% of water vapor is concentrated in the troposphere, many weather phenomena such as clouds, fog, rain and snow occur in the troposphere.

floor

In the troposphere, according to the distribution characteristics of airflow and weather phenomena, it can be divided into low layer, middle layer and high layer.

(1) Lower layer: The lower layer is also called disturbance layer or friction layer. It generally ranges from the ground to a height of 2 kilometers. With the difference of seasons and days and nights, there are some changes in the scope of the lower layer, which is generally higher in summer than in winter and higher in day than at night. In this layer, the airflow is greatly influenced by ground friction, and the turbulent exchange is particularly strong. Usually with the increase of height, the wind speed increases and the wind direction deflects. This layer is affected by the ground thermal effect, and the temperature also has obvious diurnal variation. Because of the high content of water vapor and dust particles in this layer, low clouds, fog and floating dust often appear.

(2) Intermediate layer: The bottom boundary of the intermediate layer is at the top of the friction layer, and the height of the upper layer is about 6 kilometers. The influence of the ground is much less than that of the friction layer, and the airflow can basically represent the air movement trend of the whole troposphere. Most of the clouds and precipitation in the atmosphere are generated in this layer.

(3) Upper layer: The upper layer extends from a height of 6 kilometers to the tropopause. This layer is less affected by the ground, the temperature is below 0℃ all the year round, the water vapor content is less, and all kinds of clouds are composed of ice crystals and supercooled water droplets. In mid-latitude and tropical areas, strong wind belts with wind speed equal to or greater than 30m/s often appear in this layer, which is called jet stream.

In addition, between the troposphere and the stratosphere, there is a transitional layer with a thickness of several hundred meters to 1 ~ 2 kilometers, which is called the tropopause. The main feature of this layer is that the temperature drops suddenly with height. The changes are as follows: the temperature decreases slowly with the increase of height, or is almost isothermal. According to the initial height of this change, the position of the tropopause is determined. Tropospheric temperature in low latitudes.

The average temperature is about -83℃, and it is about -53℃ at high latitudes. The tropopause has a great blocking effect on the vertical airflow, and the rising water vapor and dust particles gather under it, which makes the visibility there often poor.

Temperature change

Variation of Tropospheric Temperature with Height

In the troposphere, because the direct source of its main heat is ground radiation, the temperature decreases with height. The troposphere temperature in Qinghai-Tibet Plateau is obviously higher than that in other areas at the same height, because it improves the position of ground radiation.

The general law of troposphere changing with height: the temperature drops by 0.65℃ every time the height rises 100 meters.

Because of this change in temperature, there is a strong air convection movement.

Stratosphere, because it is far from the ground, the influence of ground radiation on it can be ignored, and its heat comes from solar ultraviolet radiation absorbed by ozone. So it is cold and hot, and the atmosphere mainly flows horizontally.

The middle layer, also known as the upper troposphere, is also cold at the top and hot at the bottom, with obvious convection. (Away from the ozone layer again)

Near the ground, where the temperature is high, the air moves upward, and where the temperature is low, the air moves downward, forming air convection. When the troposphere temperature is high and low, air convection is easy to occur. Significant convective movement and sufficient water vapor make the weather phenomena in the troposphere complex and changeable, and the main weather phenomena such as clouds, rain, snow and lightning all occur in this layer. Various weather changes in the troposphere affect the survival and behavior of organisms, and the troposphere is the layer in the atmosphere that is most closely related to people's life and production.

Tropospheric distribution and temperature change _ Introduction of articles related to tropospheric physical geography;

1. High school geography and atmosphere questions and answer templates

2. High school geography and atmospheric knowledge points

3. Special knowledge points of geography and atmosphere in senior high school

4.20 19 A round of review of geography in college entrance examination: summary of important knowledge points of geography in senior high school.

5. The meaning of troposphere and sentence making

6. One of the important knowledge points of geography compulsory in senior one.

7.20 16 knowledge points of geography college entrance examination

8. Summary of compulsory knowledge points of geography in senior one.

9. Senior three geography preparation knowledge: atmosphere

10. High school geography and atmosphere questions and answer templates