What are the main factors affecting the climate in South America?
Geographical location and continental shape are the main factors that form the climate characteristics of South America.
First, the location of land and sea. South America borders on the Atlantic Ocean and the Pacific Ocean, and is significantly influenced by the ocean, with a small range of arid climate zones.
Second, the latitude position. South America is roughly between north latitude12 and south latitude 56. The equator crosses the north, and about 2/3 of the area is located in the tropics. It belongs to the subtropical and temperate regions south of the Tropic of Capricorn, and there is no frigid climate except in mountainous areas.
Third, the outline of the continent is triangular, which is wide in the north and narrow in the south, that is, the low latitude area is wider and the middle latitude area is narrower. This is an important reason why the tropical and subtropical climate area in South America is large and the temperate climate area is small, and the southern continent is fragile to the ocean.
Fourth, the terrain. The influence of topography on the climate in South America is mainly the Andes. The Andes is the main barrier of climate in South America, which can prevent the air mass from entering the inland to some extent. The western edge of the Amazon plain, the west coast of Colombia and the west coast of Chile, south of 40 south latitude, are all topographic precipitation, forming a rainy zone in South America. However, the Patagonia Plateau on the leeward slope is difficult to disappear because of the foehn effect caused by the airflow from the west. Form an arid and semi-arid climate. The eastern part of the Andes is vast, and the plains and plateaus are very conducive to the westward inland and north-south movement of the Atlantic air mass, resulting in a rainy climate in the eastern slope of the Andes. The north and south of the equator form a tropical rain forest and savanna climate type with north-south symmetry and zonal extension. Thirdly, the Andes have high terrain and obvious vertical climate change, while the South Andes has high latitude and abundant precipitation, which is easy to form glaciers.
Fifth, ocean currents. The east and west sides of the South American continent are respectively affected by the Brazilian warm current and the Peruvian cold current.
The Guyana Warm Current, which diverges from the northern part of the east coast, flows northwest along the coast, making the weather near the mouth of the Amazon River and the coastal areas of Guyana and Venezuela hot and humid. The Brazilian warm current from the southern branch of the east coast flows southward to the mouth of the La Plata River, which raises the coastal temperature and produces abundant precipitation.
On the west coast, there is a strong Peruvian cold current flowing northward, almost reaching the equator, causing the coastal temperature to drop, resulting in inversion and low-level fog, making it difficult to form convective rain. Therefore, there is a lack of precipitation, and an arid Atacama desert is formed between 20 and 30 degrees south latitude. The west coast north of 6 south latitude is affected by warm and humid equatorial countercurrent, and the water temperature is high. When this high warm current meets the cold current in southern Peru, it is easy to cause airflow convergence.
Sixth, atmospheric circulation. The weather and climate in South America are mainly controlled by four atmospheric activity centers: the North Atlantic subtropical high, the South Atlantic subtropical high, the South Pacific subtropical high and the equatorial low. Their positions move north and south with the change of seasons, which affects the wind direction and air mass activities all over the mainland and forms different climates.
In July, the equatorial low moved northward to near north latitude 10. At this time, the sphere of influence of the two subtropical high in the South Atlantic and the South Pacific has expanded, and it can be connected in the northern inland of Argentina, while it seldom rains in the inland of South America. In June+10, 5438, the South American continent generally warmed up, and the equatorial trough moved south to the south of the equator, separating the two high pressures of the South Atlantic and the South Pacific. The interior of the mainland near the Tropic of Capricorn becomes the center of equatorial low pressure, which is controlled by unstable equatorial ocean air mass, resulting in rainy inland areas of Brazil and Paraguay.
In the vast northern part of eastern South America, northeast winds and southeast winds prevail all the year round, which are mainly controlled by the tropical North Atlantic air mass and the tropical South Atlantic air mass. The northeast wind of the tropical North Atlantic air mass reaches South America, which is unstable, warm and humid and brings abundant precipitation. July is mainly prevalent in the north of the equator. 65438+ 10 month, crossing the equator, the northwest wind reaches the parana river river basin. The air mass in the tropical South Atlantic is warm, humid and unstable. In July, the air mass invaded the mainland with the southeast wind, extending to the south of the equator and east of the Andes. In the south of 20 north latitude, the air mass blows to the southeast coast of Brazil with the northeast trade wind, and goes deep inland, reaching the eastern slope of the Andes, and often meets the polar gas invading northward, forming polar front precipitation. 48660.68868888686
The west of South America, the west coast of 3-30 south latitude, is mainly influenced by the tropical South Pacific air mass. The air mass originated in the tropical high pressure area, and the airflow sank obviously. The southeast wind prevailing here is close to the sea breeze, which is not easy to rain, forming a tropical arid climate, and it is the region with the least rain in South America. The tropical South Pacific air mass moved northward near the equator and degenerated into a humid and unstable equatorial Pacific air mass. The southwest wind enters the coastal area north of the equator and produces abundant precipitation through topographic uplift. On the west coast of 30-37 south latitude, the center of high pressure moves southward in summer, which is controlled by the subtropical high in the South Pacific, with little precipitation. In winter, the center of high pressure moves northward, blowing northwest wind, bringing hot and humid unstable marine air mass, forming a Mediterranean climate with mild and rainy winter and cool and dry summer. The westerly winds prevail all the year round on the west coast south of 37 south latitude, and the tropical ocean air mass meets the polar ocean air, resulting in a polar front, which makes the western slope of the Andes in southern Chile rainy and rainy. When the polar ocean air passes through the Andes and reaches the Patagonia Plateau, wind burning will occur, which will reduce the drought.