Physical geography of South Asia
1. Land and sea location: it is near the Himalayas in the north, the Indian Ocean in the south, the Arabian Sea in the west and the Bay of Bengal in the east, roughly between the Himalayas and the Indian Ocean.
2. longitude and latitude positions: ~ 37 n, 6 e ~ 97 e
3. adjacent position: north side: China; Southeast side: Southeast Asia; Northwest side: West Asia.
4. climate: most areas have tropical and subtropical monsoon climate, and a year is divided into hot season (March-May), rainy season (June-September) and cold season (October to February).
5. Crops and minerals: rice, wheat, sugarcane, jute, rapeseed, cotton, tea and other crops are abundant. It contains coal, iron, manganese, mica, gold and other mineral deposits. 2 landlocked countries: Bhutan, Nepal
3 coastal countries: India, Pakistan, Bangladesh
2 island countries: Sri Lanka, Maldives
1 region: Kashmir South Asia is divided into three parts: Himalayan mountains in the north, with an average elevation of over 6, meters and 14 peaks above 8, meters. Mount Everest between Nepal, India and China is 8,844.43 meters above sea level, which is the highest mountain in the world. The vertical changes of climate, soil and vegetation are remarkable. The central part is the Great Plain (formed by the Indus River, Ganges River and Brahmaputra River), with dense river network, numerous irrigation canals and developed agriculture. Deccan Plateau and coastal plains on the east and west sides are in the south. Between the plateau and the coastal plain are the East Gaozhi Mountains and the West Gaozhi Mountains. Rivers such as Godavari and Krishna flow from west to east and flow into the Bay of Bengal. Rich in rice, wheat, sugarcane, jute, rapeseed, cotton, tea and so on. Rich in coal, iron, manganese, mica, gold and other minerals.
South Asia is separated from the main body of the Asian continent by the high Himalayas in the north, surrounded by the Bay of Bengal, the Arabian Sea and the Indian Ocean in the east, west and south, which makes South Asia a relatively independent unit in geography. Therefore, the mainland part from the south of the Himalayas to the Indian Ocean is called the "South Asian subcontinent" (or the subcontinent for short). South Asia, on the other hand, is made up of most of the South Asian subcontinent and the nearby islands in the Indian Ocean. The northern part is a long, narrow and rugged mountain on the south side of Himalaya, the middle part is a slightly curved and broad Ganges-Indus lowland, while the southern part is a slightly higher in the west and lower in the east, with gentle ups and downs.
The boundaries in South Asia are obvious. Young folded mountains (such as Suleiman Mountains in the northwest, Karakorum Mountains in the north, Himalayan Mountains in the east, Badakai Mountains and Arakan Mountains, etc.) surround the peninsula in the north and face the sea in the south. The central plain is alluvial by the Indus River and Ganges River. The Indus River originates from Tibet, China, flows through the arid area of western South Asia and flows into the Arabian Sea. The Ganges River originates from the Himalayan region in the northwest, flows through India and Bangladesh, and flows into the Bay of Bengal, with the Ganges Delta at its mouth.
The causes of thar desert in the northwest of South Asia are as follows: ① The subtropical high pressure zone controls in winter, with little precipitation; ② The southwest monsoon can't reach in summer; ③ Overexploitation of Indus Valley. Most parts of South Asia have a tropical monsoon climate. A year is divided into hot season (March-May), rainy season (June-October) and cool season (November to February). The temperature is high all year round and the precipitation varies greatly from place to place. The rainfall on the windward slope of southwest monsoon is extremely rich, which is one of the regions with the highest rainfall in the world (such as Kilapangqi, India). In the northwest, precipitation is scarce.
most of south Asia is located in the north of the equator and south of 3 north latitude. except for the tropical desert climate in northwest India and southern Pakistan, most other areas have tropical monsoon climate. The formation of monsoon climate in South Asia is closely related to the difference of thermal properties between land and sea, the seasonal movement of wind belt in pressure zone and the topography of Qinghai-Tibet Plateau.
According to the advance and retreat of monsoon, South Asia can be divided into three seasons: cool, hot and rainy. From November to February, the northeast monsoon blowing from the mainland to the ocean brings sunny, dry and cool weather, which is a cool season. In the cool season, the daily temperature range is large, there is some cyclone rain in the northwest, and there is also more precipitation on the east coast of the Indian Peninsula. From March to May, as the direct point of the sun moves northward, the temperature rises rapidly and the climate is hot and dry, which is called hot season. The temperature in the central part of Deccan Plateau reaches 35℃, and the absolute maximum temperature in thar desert has reached above 5℃, sometimes sandstorms occur. From June to October, due to the continuous high temperature in South Asia, a thermal depression occurred in the northwest of India, which strongly attracted the southwest monsoon deflected by the southeast trade winds across the equator, thus further strengthening the influence of the southwest monsoon. The southwest monsoon passes through the vast and warm tropical ocean and is full of water vapor, which brings abundant precipitation to most parts of South Asia and forms the rainy season. 9% of the annual precipitation is concentrated in the rainy season. The rainy season comes at the earliest time in the west of the peninsula and the latest in the northwest of India. The late arrival and early departure of the southwest monsoon is one of the main reasons for the large rainfall variability in South Asia. October-November is the end of the rainy season, and the temperature begins to decrease gradually, and the air pressure in the northern area also increases gradually, so the air pressure gradient between land and sea gradually weakens, so the southwest monsoon begins to shrink, the precipitation decreases, and soon it turns back to the cool season.
Tropical rain forest and tropical monsoon forest occupy a vast area in South Asia, and their distribution is closely related to precipitation. The west reaches the west of the mountain, the south of the Himalayas in the east, Assam area and most of Sri Lanka Island, and the annual precipitation is more than 2, mm, which is a tropical rain forest area; Most of the annual precipitation in Deccan Plateau is 1, ~ 2, mm, and trees shed leaves in dry season in order to reduce evaporation in hot season. The annual precipitation in Deccan Plateau and the northwest of Indian Peninsula is between 5 ~ 1, mm, mostly shrubs and grassland vegetation; Thar desert and its surrounding areas, with little rainfall, are desert and semi-desert, where only sparse herbs and spiny shrubs grow. The strength of southwest monsoon comes early and late, which has an important impact on agricultural production in South Asia.
There is a alpine climate in the northern Himalayas. There are some tropical desert climate distribution in the Indus Valley, and the seasonal movement of pressure belt and wind belt makes southwest monsoon blow in summer and northeast monsoon blow in winter, which is one of the main reasons for the formation of tropical monsoon climate.
Climatic characteristics of South Asia:
(1) There are three tropical climate types ▲ The southern part of Maldives and Sri Lanka Island has a tropical rain forest climate ▲ The northwestern part of India and the southern part of Pakistan have a tropical desert climate ▲ The Indian Peninsula, the Ganges Plain and the southern foot of the Himalayas have a tropical monsoon climate
(2) The tropical monsoon climate widely distributed in South Asia ▲ The causes of tropical monsoon ▲ The thermal difference between land and sea between the Asian continent and the Indian Ocean; Seasonal movement of pressure belt and wind belt (moving northward in summer); The low pressure center in northern India strengthens the southwest monsoon. ▲ Features of the monsoon climate in the south subtropical zone: a year is divided into three seasons: cool, hot and rainy. Dry season: cool season: the northeast monsoon prevails in February of October every year, which is sunny, dry and cool; Hot season: from March to May every year, the northeast monsoon prevails, sunny, dry and hot; Rainy season-from June to September every year, southwest monsoon prevails, with high temperature, humidity and abundant precipitation.
(3) The tropical desert climate in the Indus Valley. Rivers: There are three major rivers in South Asia, namely Indus River, Ganges River and Brahmaputra River. The source of the Indian River leaves China (its source river is called Senge Zangbo), turns southwest and flows south, and flows into the Arabian Sea. It is the most important irrigation water source in Pakistan.
Since ancient times, the Indus Plain has been a developed area of irrigated agriculture in South Asia. The source of the Henghe River rises from the southern foothills of the Himalayas and flows through the Ganges Plain. The Brahmaputra River flows through the three countries, with its upper reaches in China, called the Yarlung Zangbo River, its middle reaches in India, and its lower reaches meet the Ganges River in Bangladesh and flow into the Bay of Bengal. These two rivers are in the estuary area, alluvial into a large Ganges Delta, where the world's largest high-quality jute producing area is located. Iron, manganese and coal are the most abundant mineral resources. South Asia is the origin of cultivated plants such as mango, castor, eggplant, banana, sugarcane and lotus root. Jute and tea produced account for about 1/2 of the world's total output. The output of rice, peanut, sesame, rapeseed, sugarcane, cotton, rubber, wheat and desiccated coconut also occupies an important position in the world. Tropical rain forest and tropical monsoon forest occupy a vast area.
it is rich in rice, wheat, sugarcane, jute, rapeseed, cotton and tea. Rich in coal, iron, manganese, mica, gold and other minerals. Iron, manganese and coal are the most abundant mineral resources. South Asia is the origin of cultivated plants such as mango, castor, eggplant, banana, sugarcane and lotus root. Jute and tea produced account for about 1/2 of the world's total output. The output of rice, peanut, sesame, rapeseed, sugarcane, cotton, rubber, wheat and desiccated coconut also occupies an important position in the world. The main crop in the Indus Plain is wheat;
Deccan Plateau is suitable for cotton growth because of its high altitude and sufficient heat.
the main crop in the Ganges valley is rice.