Types and distribution of global climate

The mid-latitude zone is the intersection of tropical air mass and polar air mass. The main circulation systems that affect climate are polar front, prevailing westerly wind, extratropical cyclone and anticyclone, subtropical high and tropical cyclone. The weather changes aperiodically and the precipitation changes seasonally. The land mid-latitude climate zone is a region where cold and warm air currents compete with each other, and the seasonal and aperiodic changes of temperature and precipitation are remarkable. According to the heat condition, the mid-latitude climate zone on land can be divided into temperate zone and subtropical zone. Because the global continent is most seriously divided by the ocean in the mid-latitude region, there are often different climatic phenomena and characteristics on the east and west sides of the continent and within the continent, which show as dry and wet zones, thus affecting the regional differentiation of the natural environment.

1. Land temperate climate

The land temperate zone is mainly distributed in the region of 35 ~ 60 N, and the temperate zone in the southern hemisphere is not large, because only a small piece of land extends to the south of 40 N. Due to the influence of ocean division, the temperate zone has obvious east-west differentiation. Generally, the east coast of the mainland has a temperate continental humid climate or temperate monsoon climate, the west coast of the mainland has a temperate maritime climate, and the inland between them has a temperate continental arid and semi-arid climate.

(1) temperate continental humid climate

It is mainly distributed in the eastern part of North America and the eastern part of Eurasia temperate maritime climate zone between 35 and 55 north latitude, that is, the eastern part of Eurasia temperate maritime climate zone and the area about 40 to 60 N east of North America100 W. The temperature and precipitation of this climate are somewhat similar to those of temperate monsoon climate, but the seasonal changes of wind direction and wind force are not as obvious as those of temperate monsoon climate. From the cause of formation, its cold and dry winter is not caused by the continental monsoon, but by the deep westerly wind blowing from the ocean, which has undergone continental degeneration, so the temperature is low and the precipitation is less; There is convective rain in summer, but the concentration of summer rain is not as significant as that of temperate monsoon climate.

(2) temperate maritime climate

It is mainly distributed in the western part of the mainland at 40-60 north latitude, including the western and southern Scandinavia in Europe, most parts of central and western Europe, the Pacific coast west of cordilleras in North America and Canada, the western Andes in southern Chile in South America, and Tasmania and New Zealand in Australia. The westerlies and temperate marine air masses prevail here all the year round, and warm currents pass along the coast, forming a climate characteristic of warm in winter and cool in summer, small annual variation, more precipitation throughout the year and a little more rainfall in autumn and winter. Besides, it's rainy, cloudy and sunny here.

(3) temperate monsoon climate

It is mainly distributed in East Asia near 35-55 N, including the north of Qinling-Huaihe Line in eastern China, the Korean Peninsula, northern Japan and southern Russian Far East. The climate is similar to the subtropical monsoon climate. Winter is controlled by temperate continental air mass, which is cold and dry with large temperature difference between north and south; In summer, it is warm, hot and rainy, and the temperature difference between north and south is small due to the influence of temperate marine air mass or denatured tropical marine air mass. In addition, the four distinct seasons and significant weather non-periodic changes are also the main characteristics of temperate monsoon climate. Because the climate characteristics of the above temperate climate types are mainly humid (semi-humid in North China Plain and Northeast China Plain), temperate broad-leaved forest landscape (forest and grassland landscape in North China Plain and Northeast China Plain) is generally developed, but there are some differences. There are more kinds of broad-leaved trees in East Asia than in Europe, including Quercus mongolica, Quercus liaotungensis, Acer, Tilia lindleyana, Birch and other miscellaneous trees. In western Europe, pure forests composed of single tree species are often formed, such as beech forests and oak forests. The broad-leaved forest landscape in North America (including the southern Great Lakes, Appalachian Mountains, Mississippi River Basin and Atlantic coastal lowlands) is dominated by American beech and sugar maple. Colored brown soil and gray brown soil are mainly developed in the whole temperate moist broad-leaved forest belt, while cinnamon soil and black soil are mainly developed in semi-humid forest grassland belt.

(4) temperate continental arid and semi-arid climate

Also known as temperate desert and temperate grassland climate, it is mainly distributed in the hinterland of Asia and North America, Patagonia Plateau and pampas grassland in South America. This climate zone in Asia and North America is far away from the sea, deep inland, surrounded by mountains and plateaus, and it is difficult for humid ocean air to reach. Temperate continental air masses prevail all the year round, forming a temperate continental arid and semi-arid climate with hot summer and little rain in winter. Generally speaking, the average annual precipitation in arid climate is below 250 mm, and the average annual precipitation in semi-arid climate is 250-500 mm. This climate zone in South America is located on the east coast of the continental westerly belt, which is a rain shadow zone, and there are tall Andes mountains on the west coast. The west wind sinks after crossing the mountain, which is warm, dry and rainy, and there is a cold current along the coast, so the air is stable and precipitation is scarce. The vegetation in temperate continental arid climate is sparse, and the vegetation land type is temperate desert soil; The vegetation soil type in temperate continental semi-arid climate zone is temperate grassland chestnut soil.

2. Terrestrial subtropical climate

Terrestrial subtropics are mainly distributed in areas between 25 degrees and 40 degrees north and south latitude. Due to the subtropical high and the location of land and sea, the east coast of the mainland generally has a subtropical humid climate or a subtropical monsoon climate; The west coast of the mainland has a subtropical summer dry climate (Mediterranean climate); There is a subtropical continental arid and semi-arid climate between them.

(1) subtropical humid climate

It is mainly distributed in the 25°-35° N zone in the east of North America, the southeast edge of Brazil Plateau in South America, the east of the middle and lower reaches of parana river, and the east of pampas Grassland. In addition, it is also distributed in the southeast coast of Africa and the southeast coast of Australia, but the area is small. Its main feature is that the temperature difference between winter and summer is smaller than that in subtropical monsoon climate zone, and the precipitation distribution in one year is even than that in monsoon climate zone. These areas are similar to the East Asian subtropical monsoon climate zone (the east coast of the mainland) in latitude and land and sea position, but because the mainland area and adjacent ocean area are small, the thermal difference between land and sea is not as prominent as the latter, so a typical monsoon climate has not formed.

(2) Subtropical monsoon climate

It is distributed in subtropical East Asia, mainly including the area south of Qinling-Huaihe River in eastern China, the area north of tropical monsoon climate zone, southern Japan and the southern tip of Korean Peninsula. The change of air pressure configuration caused by different sea-land temperatures in winter and summer is the main reason for the climate in this area. In winter, the Asian continent is controlled by the high pressure, and the northwest wind blows from the land to the ocean, that is, the winter wind, with less precipitation; In summer, the Asian continent is controlled by low pressure, from the southeast wind blowing from the ocean to the land, that is, the summer monsoon, with more precipitation.

Evergreen broad-leaved forest is the main vegetation in subtropical humid climate and monsoon climate, and the corresponding soil types are red soil and yellow soil.

(3) subtropical dry summer climate

Also known as the Mediterranean climate, it is mainly distributed on the west coast of the mainland at 30-40 degrees north and south latitude. The Mediterranean region has the largest summer drought climate range and the most obvious characteristics. In addition, it also includes the Pacific coast of the southwestern United States, central Chile, the southern tip of Africa and the southern tip of Australia. The planetary wind system on the west coast of subtropical continent is normally distributed, and the climate here is controlled by the seasonal alternation of subtropical high and westerly winds. In summer, this area is controlled by subtropical high pressure zone, dominated by downdraft, and the climate is dry and hot; Winter is controlled by westerlies, where temperate ocean air masses prevail, cyclones are active and precipitation is high. Therefore, hot and dry summer and mild and rainy winter are the main features of the Mediterranean climate. This type of climate zone mainly forms evergreen broad-leaved forest belt, mainly evergreen shrub forest and brown soil.

(4) subtropical continental arid and semi-arid climate

It is mainly distributed in the subtropical continent, including the Iranian Plateau and Anatolia Plateau in West Asia, the inland plateau in the western United States and Granchako in South America. The arid climate is formed because the inland is far away from the sea or blocked by mountains, and the humid ocean airflow is difficult to reach, and it is located in the subtropical zone, so it is hot in summer and mild in winter. Semi-arid climate belongs to the type of transition from arid climate to other climate. The vegetation here belongs to desert grassland, usually xerophytes and gramineous plants, and the soil belongs to semi-desert light brown soil.

(3) Land high latitude climate

The land high latitude climate zone mainly includes the sub-frigid zone north of 50' north latitude in the northern hemisphere, the land frigid zone in the Arctic Circle and the Antarctic continent in the southern hemisphere. Arctic Ocean and Antarctic ice sheet are the sources of glacial air mass and Antarctic air mass respectively, while Siberia and Canada are the sources of polar continental air mass in Asia and North America respectively. On the ice front where the ice air mass meets the polar air mass, a cyclone moves from west to east. The temperature here is low, including the world cold pole and the northern hemisphere cold pole. The main climate types are sub-frigid continental climate, polar long cold climate and polar ice sheet climate. The characteristics of several climatic zones are:

1. Subrigid continental climate

Also known as the sub-cold zone coniferous forest climate, it is generally distributed between 50 and 70 north latitude, and the west coast of the mainland is between 60 and 70 north latitude, including most of North Asia, Northern Europe, Alaska in North America and central and northern Canada. The climate here is mainly influenced by the polar ocean air mass and the polar continental air mass, and it is the source of the polar continental air mass. In winter, there are many opportunities for ice air masses to invade; In warm seasons, tropical continental air masses can also penetrate. The climate is characterized by strong continental nature, long and cold winter, short warm season, high annual temperature difference, little precipitation, concentrated warm season and weak evaporation, belonging to a cold and humid environment. Vilho Yansk and Oymyakon in the northeast of Siberia, with an average temperature of -50℃ in June+10/October in 5438 and an absolute minimum temperature of -73℃, are cold poles in the northern hemisphere. The absolute annual temperature difference of Vilho Jansk reaches 65,438+0,065,438+0.8℃, which is the highest annual temperature difference.

2. Long-term cold climate in polar regions

Also known as tundra climate, it is mainly distributed on the coasts and islands of the Arctic Ocean in Eurasia and North America, and the latitude is roughly between 70 and 75 N, which is already within the Arctic Circle, so the extreme phenomenon of day and night is obvious. The climate is characterized by winter all year round, with the monthly average temperature of 0-IO ~ C for only 65,438+0-4 months in a year, and the precipitation is scarce, which mostly belongs to the glacier front, mostly snow, with plenty of clouds and weak evaporation.

3. Polar ice sheet climate

Mainly distributed in the Antarctic continent, the Arctic Ocean and most parts of Greenland. The latitude is the highest here, and the longest day and night can last for half a year. Controlled by polar high pressure for many years, it is the source of ice ocean air mass and Antarctic air mass. It is very cold all year round, with little precipitation, and snowstorms are common. Due to years of accumulation, a huge ice sheet has been formed. The Antarctic region is the world's cold pole, wind pole and the driest ice continent, while the Arctic region is a sea of ice sheets and floating ice.

(4) Plateau climate

Mainly distributed in the Himalayas, Pamirs and Qinghai-Tibet Plateau in Asia, Cordillera Mountains in North and South America, Alps in Europe and Kilimanjaro in Africa. Because the climatic factors such as temperature and precipitation change vertically with the altitude of the terrain, a vertical climate zone structure is formed. Different mountains or plateaus have different vertical climate zone structures, that is, the same mountain or plateau often has different vertical climate zone structures due to the differences in internal slope direction, height and position.