Three compulsory knowledge points of geography in senior three.

# Senior 3 # Introduction Senior 3 students are about to face the choice of continuing their studies or their careers. Have you considered the important life choices clearly? This is undoubtedly a difficult choice for students without social experience. How to spend this important and tense year can start with improving learning efficiency! The third channel of senior high school has compiled three compulsory knowledge points of geography for all students. I hope you study hard and have a golden dream in June!

1. Three required knowledge points of geography in senior three.

The Qinghai-Tibet Plateau is located in the west of Minshan-Qionglai-Jinping Mountain in the southwest of China, between Kunlun Mountain, Altun Mountain, Qilian Mountain and Himalayan Mountain, with an average elevation of over 4,000 meters. It is a great plateau with an altitude of 8844.43 meters, and is known as the "roof of the world". The Qinghai-Tibet Plateau was originally a part of the ancient Mediterranean sea floor. Later, in Pliocene-Pleistocene, under the interaction of Asia-Europe plate, Pacific plate and India plate, the rigid Indian plate was pushed by the Indian Ocean expanding northward, and swooped and squeezed along the suture line of Yarlung Zangbo River to the southern edge of the Asian continent. Because of its low latitude, high terrain, low air density, strong solar radiation, long sunshine time and large volume, the Qinghai-Tibet Plateau has formed a plateau monsoon climate, which is not too cold in winter, cool in summer, with small annual temperature difference and large daily temperature difference.

The uplift of the Qinghai-Tibet Plateau has also had a far-reaching impact on the climate in China.

(1) Blocking effect of Qinghai-Tibet Plateau on westerly airflow

The Qinghai-Tibet Plateau blocked the low-level westerly airflow in China and divided it into two branches (the branch point is 60 E). The north branch airflow flows to the Pacific Ocean through the northwest, north China, northeast China and east China. After flowing through the south side of the Qinghai-Tibet Plateau, the south branch airflow turns into a southwest airflow with high temperature and humidity, which affects Sichuan, Guizhou, Yunnan, South China and the middle and lower reaches of the Yangtze River in China. The last two air streams converge near 1 10 E in the eastern part of the Qinghai-Tibet Plateau. As shown in figure 1.

In winter, the westerly jet near the ground in China moves south, and the blocking force of its northern branch airflow will be weakened by the Qinghai-Tibet Plateau near the ground, making the climate in the vast areas of northern China cold and dry; However, the airflow in its south branch will be strengthened, and it will meet the cold air in the south in Kunming and Guiyang, forming a quasi-static front in Kunming, which will cause a lot of snowfall in Sichuan, Guizhou, Hanshui River Basin and even Shandong and Liaoning.

In summer, the westerly jet near the ground in China moves northward, and its southern branch airflow will be weakened by the near-ground blocking force of the Qinghai-Tibet Plateau, making some areas on the southern edge of the Himalayas have the least wind and the most stable weather; Its north branch airflow is just the opposite. With the strengthening of the southwest monsoon, the southwest warm and humid airflow will bring a lot of precipitation to the Yangtze River basin and the Pearl River basin in China. The air flow in the northern part of the Qinghai-Tibet Plateau has obvious influence on China, for example, there are many cyclones in northwest China in spring.

In winter, due to the blocking effect of the Qinghai-Tibet Plateau and the influence of topography, the Sichuan Basin is prone to cloudy weather with low wind speed and high air humidity. In summer, due to the "leeward slope" of the Qinghai-Tibet Plateau, if the southwest warm and humid airflow moves south and the southeast monsoon moves westward, it is prone to drought.

(2) The shielding effect of Qinghai-Tibet Plateau on cold and warm air flow.

In winter, because the air at higher latitudes is difficult to cross the Qinghai-Tibet Plateau, the area south of the Qinghai-Tibet Plateau is less affected by the winter wind, and the temperature drops slightly. In summer, the southwest monsoon from the Indian Ocean rarely crosses the Qinghai-Tibet Plateau and enters the northwest of China, so the climate in Gansu and Xinjiang will be relatively dry.

(3) The Qinghai-Tibet Plateau promotes the winter and summer monsoon in China.

The uplift of the Qinghai-Tibet Plateau has formed a relatively independent climate unit in eastern China, which makes the thermal properties of land and ocean in China extremely different. Due to the high terrain, the atmosphere over the Qinghai-Tibet Plateau is heated quickly in summer, and the air flow rises and the air pressure drops, which accelerates the formation of land depression, strengthens the summer monsoon blowing from the ocean to the land, and even affects the eastern and southern parts of the Qinghai-Tibet Plateau. As shown in figure 2. In winter, the air over the Qinghai-Tibet Plateau cools rapidly, and the airflow sinks, which strengthens the land high-pressure forces and urges the airflow to blow from the land to the sea. As shown in figure 3.

Due to the uplift of Qinghai-Tibet Plateau, the circulation force of East Asian monsoon in China is stronger, the replacement of winter and summer monsoon is more obvious, the continental climate characteristics are more prominent, and the influence of winter monsoon is longer and wider.

(4) The influence of Qinghai-Tibet Plateau on precipitation in South China.

Due to the uplift of the Qinghai-Tibet Plateau, a relatively independent monsoon climate zone has been formed in eastern China. Coupled with the influence of typhoon, the precipitation in the south of China is extremely rich, and it has got rid of the bad luck of becoming a desert under the control of subtropical high and become an "oasis" on the Tropic of Cancer.

In short, the uplift of the Qinghai-Tibet Plateau not only formed a unique plateau climate, but also had a far-reaching impact on the climate in China, making the climate in China complex and diverse.

2. Three compulsory knowledge points of geography in senior three.

Advantages of valley areas

The advantages of the valley area are mainly concentrated in agriculture, such as relatively low altitude and high temperature; Strong solar radiation and abundant sunshine; The valley area is flat; The soil is deep and fertile; Near the river, there is a lot of water.

1 what is valley agriculture?

The agriculture developed in the valley area is called valley agriculture, which is generally distributed in strips or strips along the river. The mountainous valley area has low terrain, high temperature, long frost-free period and good precipitation conditions, which is suitable for farming. This river can also be used as irrigation water source. The mountains on both sides of the valley are generally forests, which makes the soil in the valley rich in humus and very fertile. Valley agriculture is developed, which is called valley agriculture. For example, the Yellow River Basin and Huangshui Basin in Qinghai Province are typical valley agricultural areas and the main agricultural areas in Qinghai Province. The Yarlung Zangbo River basin is also a valley agriculture. There are also on the Qinghai-Tibet Plateau.

Why is the temperature higher in the valley?

The high temperature in the valley area is mainly affected by mountain wind and valley wind. Mountain valley wind is a wind that blows from the valley to the hillside during the day and from the hillside to the valley at night due to thermal reasons in mountainous areas. The former is called valley wind and the latter is called mountain wind. After sunrise, the temperature of the hillside rises rapidly, which is higher than the air temperature at the same height above the valley. The horizontal temperature gradient points from the hillside to the valley, and the warm air on the hillside keeps rising and flows from the hillside to the inside of the valley. The air at the bottom of the valley supplements the air lost along the hillside, so there is a thermal cycle between the hillside and the valley. At this time, the wind blowing from the valley to the hillside is called valley wind. At night, the hillside is cooled by radiation, which is faster than the air at the same height. Cold air flows into the valley along the slope underground, forming a thermal circulation opposite to that during the day, which makes the wind blow from the hillside to the valley at this time, which is called mountain wind. The intensity of mountain breeze is generally weaker than that of valley breeze. From 20: 00 on the same day to 8: 00 on the next day, it is a mountain wind, and 14- 17 is a valley wind. Mountain valley wind is a kind of local circulation that often appears in mountainous areas. As long as the pressure field in a large area is weak, there will be mountain valley wind, and some local circulation similar to mountain valley wind can also be observed at the junction of plateau and plain.

3. Three required knowledge points of geography in senior three.

1, the atmosphere is heated.

Energy: solar radiation

Atmospheric heating process: solar radiation weakens the atmosphere, and the ground absorbs ground radiation and atmospheric inverse radiation (insulation).

2. Thermal cycle (the simplest atmospheric movement)

Sea-land thermal cycle;

Sea breeze blows during the day and land breeze blows at night.

Because the land heats up faster than the ocean during the day, the land forms a low pressure and the ocean is a high pressure; At night, the land cools faster than the ocean, and the land forms a high pressure, while the ocean is a low pressure.

3. The horizontal motion of the atmosphere:

Horizontal pressure gradient force: it is the direct cause of wind formation; The direction is perpendicular to the isobar; From high pressure to low pressure.

Geostrophic deflection: the northern hemisphere is the right hemisphere and the southern hemisphere is the left hemisphere.

Friction: it crosses the isobar obliquely. Affect the wind speed, the greater the friction, the smaller the wind speed; It also affects the angle between the wind direction and the isobar.

Wind direction: high pressure and low pressure

Wind power (wind speed): isobar density (large pressure gradient) and high wind power (speed).

4. Three compulsory knowledge points of geography in senior three.

1. Forests are not only important natural resources, but also irreplaceable environmental resources. It has many ecological functions and environmental protection effects, such as regulating climate, stabilizing atmospheric composition, conserving water, conserving soil and water, breeding species, maintaining biodiversity, preventing wind and fixing sand, smoking and removing dust, purifying air and beautifying the environment. It is called the general dispatching room of nature.

2. The existing virgin forests are mainly distributed in coniferous forests and tropical rainforests in the sub-cold zone. They are either protected from large-scale destruction because of their vast territory, sparse population and harsh natural conditions, or because they are difficult to pass and developed late. Among them, the Amazon rainforest is the original forest with existing area and relatively complete preservation on the earth. However, the trend of global forest area reduction is still intensifying, especially the tropical virgin forests are being destroyed.

3. Tropical rain forests are mainly distributed on both sides of the equator, but they can extend to the north and south latitudes 15-25 degrees in the windward zone of the mainland. The three major distribution areas of tropical rainforests are the Amazon River Basin in South America, the Congo River Basin in Africa and Southeast Asia.

4. The impact of rainforest on the global environment:

① Lung of the earth: it affects the balance of carbon and oxygen in the earth's atmosphere and regulates the global climate;

② Reservoirs of the earth: promoting global water circulation and regulating global water balance;

(3) The treasure house of biological genes in the world: the place with the most breeding species and the longest preservation time in the evolutionary history of the earth.

5. Advantages of tropical rain forest system: strong photosynthesis, vigorous biological cycle, rapid biological growth and high community productivity.

6. Vulnerability of rainforest ecology; Almost all nutrients are stored in plants on the ground, and the soil is barren.

7, Amazon rainforest development:

(1) Before 1950s: the lifestyle was backward, the development scale was small, and there was not much influence;

(2) The population has increased rapidly, and the rainforest has been destroyed unprecedentedly;

③ 1970, the Brazilian government officially announced the plan for the large-scale development of the Amazon basin: building a trans-Amazon highway, moving the capital to Brasilia, immigrating to the Amazon plain, utilizing foreign capital, and encouraging multinational enterprises to invest and develop.

8. Under the current background, in the face of the grim situation that the rainforest has been seriously damaged, protection should be given priority.

5. Three compulsory knowledge points of geography in senior three.

1, natural factors affecting the formation of debris flow:

(1) Terrain: The mountains are high and the valleys are deep, and the steep valleys are easy to make the flowing water converge quickly.

② Geology: The geological structure is complex, faults and folds are developed, the tectonic movement is strong, and the surface rocks are 99 pieces.

(3) Climate: There is heavy rain or melting snow and ice in mountainous areas.

④ Vegetation: The vegetation is seriously damaged.

Human factors:

(1) Unreasonable quarrying and mining, with a large amount of spoil and slag piled up in the valley.

(2) The engineering construction destroyed the hillside surface.

(3) Vegetation destruction and hillside vegetation protection.

2. Influencing factors of landslide formation

Natural factors:

(1) mountainous area, with undulating terrain.

② Fault development

③ Heavy rain.

Human factors:

① Improper construction of large-scale projects (such as reservoirs)

② Excavation of ditches and slopes

3. Influencing factors of the Yangtze River flood.

Natural factors:

① The areas where the Yangtze River flows are mostly wet areas, with a wide basin area, many tributaries, long flood season and large water volume. Floods are all caused by heavy rain (climate, hydrological characteristics, water system characteristics).

(2) In some years, there was a general rainstorm in the basin, and the upper reaches of the Sichuan River, the northern Han River system and the southern Dongting Lake system came at the same time, and many floods merged to form a catastrophic flood.

Human factors:

(1) Vegetation: excessive logging and steep slope land reclamation. The decrease of vegetation cover on the surface and serious soil erosion have reduced the ability of water conservation, runoff regulation, peak shaving and drought compensation in the basin.

(2) Sediment: The aggravation of soil erosion makes a large amount of sediment flow into the river, silting up the riverbed, reducing the flood discharge capacity of the river, making the drainage poor and raising the water level.

(3) Reclaiming land around the lake and silting up will cause the lake to shrink and reduce the capacity of flood peak regulation and storage.

4. Influencing factors of Jingjiang flood disaster.

① Terrain: It is located in the transitional position between Wushan and the plain. After the river leaves the mountain area, the flow rate slows down, sediment deposits and the river bed rises.

(2) The water flow is not smooth, and the sediment is deposited, forming an "overground river".

③ The river course is especially curved, with poor drainage and low flood discharge capacity.

5. Factors affecting spring drought

① Temperature: The temperature rises rapidly in spring.

② Precipitation: The rain belt has not arrived, and the precipitation is less.

③ Wind: There are many sandstorms and large evaporation.

④ Agricultural water demand is large.

6. Factors affecting flood.

① Precipitation: Precipitation is concentrated in summer, mostly heavy rain.

② Terrain: The terrain is low and flat.

③ River: Poor drainage in the lower reaches of the river.