What are the topographical features of Southeast Asia?

General situation of geographical location and topographic characteristics in Southeast Asia

Southeast Asia, the southeast region of Asia, is located in the south of China, and is customarily called the Nanyang of China. It is located at 93- 14 1.5 degrees east longitude and 25- 10 degrees north latitude. Mostly in the tropics. It borders Chinese mainland in the north, Australia in the south, the Pacific Ocean in the east, the Indian Ocean in the west, and Bengal and India. It connects three continents (Asia, Africa and Oceania) and two oceans (Pacific Ocean and Indian Ocean). The whole region consists of Indo-China Peninsula and Malay Archipelago, with a total of * * *1countries: Vietnam, Laos, Myanmar, Cambodia, Thailand, Malaysia, Singapore, Brunei, Philippines, Indonesia (the above 10 countries form the Association of Southeast Asian Nations for short), plus East Timor (a country that has been independent from Indonesia in recent years) But not yet independent) with a total area of 4.07 million square kilometers, accounting for Asia110 If Indonesia is included as a part of Oceania, that is, the western half of Irian Island, the total area is 4.48 million square kilometers. Southeast Asia consists of Indian zhina Peninsula and Malay Archipelago. Indo-China Peninsula is named after its location in the south of China. It was formerly called Indo-China Peninsula or Indo-zhina Peninsula. There are seven countries on the island: Vietnam, Laos, Myanmar, Cambodia, Thailand, Malaysia and Singapore. It covers an area of 2.07 million square kilometers, accounting for 46% of the area of Southeast Asia. The Malay Archipelago is named after its residents are mainly Malays, also known as Nanyang Archipelago, and there are four countries: Indonesia, Philippines, East Timor and Brunei. The area is 24 1 000 square kilometers, accounting for 54% of the area of Southeast Asia.

Indo-China Peninsula borders the South China Sea in the east, the Bay of Bengal and the Andaman Sea in the west, and the Straits of Malacca in the south, with a coastline of 1. 1.7 million kilometers. It is an important port with an important geographical position. Its topography is high in the north and low in the south, and the mountains are fan-shaped from north to south, with mountains and rivers alternating with each other and a long history. Its mountains and rivers are the southward continuation of the mountains and rivers in southwest China. The main mountain ranges are Naga Mountain and Rakhine Mountain from west to east. Denglao Mountain Range, Thani Taun Mountain Range and Biluoke East Mountain; Changshan mountain range. The Irrawaddy River, salween River, Chao Phraya River, Mekong River and Red River among the three mountain ranges surge from north to south. The upper reaches of rivers mostly flow through the Shan Plateau, and deep valleys divide the plateau into several parts, such as the eastern Myanmar Plateau between Irrawaddy River and salween, the Chiang Mai Plateau between salween and Mekong River, and the Laos Plateau between Mekong River and Red River. The upstream of each river has a great drop, and the river has strong scouring and conveying ability, and the downstream accumulation speed is fast, forming many vast delta plains. There are many fertile plains and deltas downstream of rivers and estuaries. The valley plains in the middle and lower reaches of some rivers and the estuary deltas of various rivers are the main agricultural areas and population concentration areas.

The Malay archipelago is scattered in the vast sea area between the Pacific Ocean and the Indian Ocean. It starts from Batam Islands in the north, Rodi Island in the south, Sumatra Island in the west and western New Guinea in the east. It is about 3500 kilometers long from north to south and 4500 kilometers wide from east to west. There are more than 20,000 islands, large and small. Including Sunda, Maluku, Philippines and Nusa Tenggara islands belonging to Indonesia, Malaysia, Brunei, Philippines and East Timor. The sea area is large, and the water depth is above 1000 meters except the Java Sea and the southern part of the South China Sea. Multi-channel is an important channel for Southeast Asia to reach the rest of the world. The terrain on the Malay archipelago is mainly mountainous, mostly distributed in the middle of the island. The plain is relatively narrow, mainly distributed in coastal areas, with only large areas in northern Java and eastern Sumatra. The Malay Archipelago is located in a place where the crustal movement is active, and earthquakes often occur due to the mutual compression of the three major plates (Pacific plate, Indian Ocean plate and Eurasian plate). While the earth's crust bulges to form mountains, the underground fiery magma also surges up along the ground fissures and erupts on the ground to form volcanoes. Indonesia and the Philippines have the largest number of volcanoes in Southeast Asia. There are more than 400 volcanoes in Indonesia, of which 120 is an active volcano. There are also 52 volcanoes in the Philippines. These volcanoes are mainly distributed in Sumatra, Java, Nusa Tenggara and some islands in the Philippines. These islands extend in an arc from east to west, so people call them "light corridors" vividly. It is the region with the most earthquakes and volcanic eruptions in the world and the "most unstable" region in Southeast Asia.

Southeast Asia is located between the Asian continent and Oceania, connecting the Pacific Ocean and the Indian Ocean. Geographical location is very important, and it has developed into a world air and sea transportation hub in modern times. The Malacca Strait on the south side is 1 185 km long, the narrowest part is 37 km wide, and the main channel is 25 ~ 15 1 m deep, which can be fully loaded with 260,000-ton ships. It is the shortest sea route and necessary passage for Northeast Asia to reach Europe and Africa via Southeast Asia. It has become the busiest sea passage in the world alongside the English Channel. In addition, the Lombok Strait, located in central Indonesia, is sandwiched between Bali and Lombok, with a length of 60 kilometers, the narrowest width of 1 1 km, and the water depth of the main channel is more than160m, which is enough for any ship to sail safely. It has become an emerging international deep-water route to replace the Straits of Malacca. Sunda strait between Sumatra and Guawa is also an important traffic artery. Together with Lombok Strait and Malacca Strait, it is called "the three gateways of Southeast Asia".

Most of Southeast Asia is in the south of the Tropic of Cancer, close to the equator, with low latitude. It is summer all year round, and it is very hot all year round. The annual temperature is between 25℃ and 30℃. A year in most areas is divided into dry season and rainy season. Generally, the dry season is June-May and the rainy season is June-June. The climate is mainly divided into two types: the northern Indochina Peninsula and the northern Philippines, which belong to tropical monsoon climate, with annual rainfall exceeding 1500mm. The area near the equator belongs to the tropical rainforest climate, which is rainy all year round. When it is not dry, the annual rainfall is more than 2000 mm.

Most areas have a tropical monsoon climate, with an average annual temperature of 20-27℃ and abundant precipitation concentrated in April-10. The southern part of Malay Peninsula has a tropical rainforest climate, with high temperature and rainy all year round.

Most of Indochina Peninsula is located between north latitude 10 ~ 20, which belongs to a typical tropical monsoon climate. March-May is a hot season every year, with the monsoon fading in winter and summer, and the climate is hot, with an average monthly temperature of 25-30℃. June ~ 10 is rainy season, with southwest monsoon prevailing and abundant precipitation; 165438+ 10 to February of the following year is a cool season, with the northeast monsoon prevailing and dry weather. The average annual precipitation is influenced by topography, with windward slopes up to 5000mm and leeward slopes less than 2000mm. A few windward slopes and Malay Peninsula areas can form a tropical rain forest landscape, and a few internal plains and valleys form a tropical grassland. The climate of Indo-China Peninsula belongs to the typical tropical monsoon type, with abundant water and heat resources and distinct wet and dry seasons, which is especially beneficial to the growth of rice. This is an important reason why rice is dominant in agricultural production in this area, but tropical cash crops are quite limited.

The southern Malay archipelago and most of the Malay archipelago (excluding the hot and rainy tropical monsoon climate in the northern Philippines) are located near the equator and belong to the tropical rainforest climate. The temperature here is high all the year round, with an average monthly temperature of 25 ~ 28℃. The annual precipitation is more than 2000 mm. Because of sufficient heat and moisture, plants flourish all year round, and dense tropical rain forests are distributed in many places. Crops can be sown at any time and harvested in any season. Rich in dried coconut, banana, pepper, cinchona cream, kapok, palm oil and so on. It is the largest production base of tropical cash crops in the world. The archipelago is also a transitional zone of biological species between the north and south continents, which has important biological significance.