What are the characteristics of the geographical distribution of precipitation on the earth?
First, the influence of latitude position on precipitation
The latitude position of 1. determines the influence of pressure zone and wind zone on precipitation. The relationship between pressure belt, wind belt and precipitation and its distribution law are as follows: near the equator-equatorial low pressure → high temperature and rainy all the year round; The interior of the mainland and the west coast of the mainland near the Tropic of Cancer-subtropical high → less precipitation; West coast of the mainland-westerly belt → mild and humid all year round; Between latitude 10 and the Tropic of Cancer-alternating control of equatorial low pressure area and trade wind area → rainy season and dry season in one year; The west coast of the mainland at 30 ~ 40 north latitude-subtropical high zone and westerly belt are alternately controlled → dry and hot in summer, mild and rainy in winter.
2. Distribution and causes of precipitation in the world. Combining pressure zone and wind zone: equatorial rainy zone, subtropical rainy zone, temperate rainy zone and polar rainy zone.
Precipitation type
Seasonal variation characteristics of precipitation
Climate type and annual precipitation (mm)
Annual rainfall pattern
Uniform seasonal distribution
Tropical rain forest climate > 2000 temperate maritime climate > 700
Summer rain type
It is rainy in summer and rainy or dry in winter.
Tropical grassland climate > 750- 1000 tropical monsoon climate > 1500 subtropical monsoon climate > 1000 temperate monsoon climate is between 500 and 600.
Winter rain type
It is rainy in winter and dry in summer.
Mediterranean climate 300-600
Less rain type
There is little rainfall throughout the year.
Tropical desert climate, temperate continental climate, sub-frigid continental climate and polar climate < 250.
name
cause
Climatic characteristics
tropical rainforest climate
It is controlled by the equatorial low pressure belt all the year round.
It is hot and rainy all year round.
Tropical savanna climate
It is controlled alternately by equatorial low pressure area and trade wind area.
The high temperature throughout the year is divided into obvious dry and wet seasons.
Tropical monsoon climate
Seasonal movement of wind zone in pressure zone and difference of thermal properties between land and sea
It is hot all year round, and there are two obvious seasons: drought and rain.
tropical desert climate
It is controlled by subtropical high pressure area and trade wind area all the year round.
High temperature and little rain all year round
Subtropical monsoon climate and monsoon humid climate
Difference of thermal characteristics between land and sea
Summer is hot and rainy, and winter is mild and rainy.
mediterranean climate
It is controlled alternately by subtropical high pressure zone and westerly belt.
Summer is hot and dry, winter is mild and rainy.
Temperate maritime climate
It is controlled by the westerly belt all year round.
It is mild and rainy all year round.
The second is the influence of atmospheric circulation (monsoon) on precipitation.
According to the annual precipitation map of China, the southeast coast is >: 1000mm, along Qinhuai is 800mm, the northwest non-monsoon area is < 400mm, and the middle of southern Xinjiang is < 50 mm. It can be concluded that the spatial distribution of annual precipitation in China is decreasing from the southeast coast to the northwest inland, which is mainly influenced by the southeast monsoon from the ocean.
For example, the average annual precipitation in Shandong Province is mostly between 550 and 920 mm, and the average annual precipitation in Shandong Province is about 7 10 mm, which is richer than that in inland provinces of the same latitude. The distribution law is that there are more in the south and less in the north, and there are more in the southeast coast than in the northwest inland. The isorainfall lines are mostly southwest-northeast, mainly influenced by the southeast monsoon from the ocean.
Thirdly, the influence of land and sea position on precipitation.
The different positions of land and sea, that is, the distance from the sea, make the land affected by the ocean in different degrees, so the distribution of precipitation will be different, resulting in a gradual (such as decreasing) distribution law from coastal to inland. At the same time, the distribution of precipitation has the following rules: there is a rainy area in the east of subtropical rainless area and a rainy area in temperate rainless area.
For example, look at the topographic profile of Manchuria (49.5 N,117.5 E)-Suifenhe (44.5 N,131E) in Northeast China. This section is northwest-southeast, and A is Hulunbeier grassland; B is Daxinganling, which is roughly where the 400 mm isoprecipitation line passes, and it is the dividing line between semi-humid area and semi-arid area; C is the northeast plain; D is Changbai Mountain. From D to A, the farther away from the sea, the less precipitation, and the gradual transition from humid and semi-humid to semi-arid areas.
Fourthly, the influence of underlying surface conditions on precipitation.
Different underlying surface conditions will have a certain impact on precipitation.
1. Influence of hillside direction on precipitation.
The precipitation difference between windward slope and leeward slope in mountainous area is obvious. The windward slope of the mountain range refers to the warm and humid airflow from the ocean. On the windward slope of the mountain range, the warm and humid airflow is forced to rise, which is easily caused by clouds. As the air sinks and the temperature on the leeward hillside rises, the precipitation will decrease. The influence of topography on precipitation depends on the change of surface slope direction, airflow direction and surface elevation. For example, the tropical rain forest climate on the east side of Madagascar is mainly located on the windward slope of the warm and humid southeast trade wind from the ocean, with a lot of precipitation, and of course it is also affected by the warmth and humidity of the Madagascar warm current.
2. The influence of topography on precipitation.
In a certain range of mountainous areas, precipitation increases with height, and decreases with height after reaching the maximum precipitation height.
For example, the precipitation at the foot of the Himalayas is obviously different from that at the top of the Himalayas: at first, with the increase of altitude, the precipitation increases, reaching the maximum at the altitude of1000 ~1500m, and then decreases with the increase of altitude.
3. The influence of forest on precipitation. Forests will have a certain impact on precipitation.
For example, the forest coverage of the large watershed in the northeastern United States will increase by 10%, and the annual precipitation will increase by 3%.
4. The influence of human activities.
Generally, human beings indirectly affect precipitation by changing the underlying surface conditions, for example, planting trees or cutting down forests on a large scale, building reservoirs, irrigating farmland, reclaiming land from lakes, draining swamps, etc. , affect precipitation (increase or decrease precipitation).
Five, the comprehensive influence of various factors on precipitation
The influencing factors of precipitation do not exist in isolation, and the amount and distribution of precipitation are often the result of the comprehensive action of many factors.
For example, the precipitation on the east and west sides of the mid-latitude continent in South America is very different. The reason why there is more precipitation on the west coast is that the warm and humid westerly winds from the ocean bring a lot of precipitation and the topographic precipitation formed by the uplift of the western mountains, while the reason why there is less precipitation on the east coast is that the western mountains (Andes) block the water vapor from the Pacific Ocean. Although it faces the Atlantic Ocean in the east, it is located in the westerly belt, near the sea breeze, and it is difficult for water vapor to enter the mainland.