What are the main causes of drought and flood disasters in South Asia?

The Northeast season is strong and the wind direction is unstable.

Answer] A Answer Analysis] Test Analysis: Due to the influence of the tropical monsoon climate in South Asia, the seasonal and interannual changes of precipitation in this region are mainly due to the influence of the southwest monsoon, and due to the instability of the southwest monsoon, the instability of precipitation leads to the instability of precipitation, which leads to frequent drought and flood disasters.

Test Center: This question examines the geography and regional climate of the world.

Comments: This question is of low difficulty, basic test questions, students only need to grasp the types of climate affecting South Asia, and analyze the impact on drought and flood disasters in combination with the instability of monsoon climate precipitation.

The main causes of drought and flood disasters are: 1. The slippage and drift of the earth's crustal plates lead to the infiltration and loss of surface water and the transfer of surface water, resulting in the loss of water on the surface; 2. Soil erosion and tree planting are destroyed; 3. Caused by astronomical tidal season; 4. Lack of water conservancy projects or fragile water conservancy infrastructure, no water conservation; 5. Failure to comply with the law of flood and drought flood season, failure to store water during floods, take water and transfer water during drought periods, and follow the laws of nature.

Promote the dynamic balance of water resources.

The impoundment of surface runoff can reach a wide key to conserve water sources, control soil erosion, and prevent the outbreak of floods on slopes, which not only protects the sloping cultivated land, but also protects the farmland downstream, and at the same time makes full and rational use of water resources, improves the ecological environment, and turns water disasters into water conservancy.

Field engineering measures are mainly to build horizontal terraces, slope terraces, ridges, etc. in sloping cultivated land, as well as adjust ridge orientation and contour operations, so as to slow down the slope, cut off surface runoff, and control soil erosion.

Water conservancy engineering measures: fundamental measures for flood prevention and waterlogging.

The main reason for the many drought and flood disasters in China is the main causeMonsoon climateEffect.

The influence of the monsoon is the main reason for the uneven distribution of precipitation in time and space, and the precipitation gradually decreases from the southeast coast to the northwest inland under the influence of the summer monsoon, and the annual precipitation is increased.

It is concentrated in summer, and winter precipitation is generally less than 10% of the year. In summer, high temperature, rain and heat are at the same time, and the hydrothermal conditions are matched or matched, so that crops and trees can get sufficient heat and water during the vigorous growth period. However, there is more precipitation in summer and is prone to flooding, while less precipitation in other seasons is prone to drought.

Due to the influence of the summer monsoon, most areas of China are rainy in summer and autumn, and there are many heavy rains, and the attacks are frequent, so they are prone to floods. Secondly, in the spring rain and plum rainy seasons, Chongling is also prone to flooding. Since the precipitation in China is related to the advance and retreat of the monsoon, once the monsoon is abnormal, it will cause abnormal precipitation, and drought and flood disasters will alternately occur in a large area.

When the summer monsoon is strong and fast, North China.

The rainy season came early, and the drought was lifted ahead of schedule, and even floods occurred, while in the south, it was sunny and rainless, and there was a severe drought.

The reason for the frequent occurrence of drought and flood disasters in China is that most of China is located in the East Asian monsoon climate.

The monsoon climate is characterized by unstable monsoons and concentrated precipitation in summer. Seasonal and inter-annual variations are significant.

The monsoon climate has a great impact on China's economic development, the summer is generally high temperature, rain and heat at the same time, the water and heat conditions are properly matched, so that crops and trees can get sufficient heat and water in the vigorous growth period, but the summer precipitation is more, easy to flood, and the precipitation in other seasons is less, easy to cause drought; When the strength of the winter and summer monsoon is abnormal, it will lead to large fluctuations in precipitation and unstable thermal conditions, resulting in drought and flood disasters, low temperatures in summer, and cold waves in winter and spring.

It often causes damage to industrial and agricultural production and even people's lives.

1.Precipitation is concentrated in summer. The middle and lower reaches are low-lying and flat.

2.The basin area is wide and the catchment area is large, especially in the year when the summer monsoon is abnormal, the north and south tributaries enter the flood season at the same time, and the flow increases sharply.

3.Vegetation was destroyed, steep slopes were cleared, and lakes were enclosed to create fields. Soil erosion is serious, the water level is rising, and the flood storage capacity of the lake is reduced.

Measures: Afforestation, returning farmland to lakes, constructing water conservancy projects, dredging river channels, cutting and straightening bends in curved sections, reinforcing embankments, and building flood distribution and storage areas.

The seasonal distribution of precipitation is uneven, and the annual precipitation varies greatly.

The eastern part of our country is a typical monsoon climate zone, under the influence of the summer monsoon, the precipitation is mainly concentrated in the month, the seasonal distribution of precipitation is uneven, if the strength of the summer monsoon is unstable, it is easy to cause the occurrence of flood and drought disasters.

Climatic characteristics. 1. High temperature all year round, the average annual temperature is above 22, and the coldest month is generally above 16 in the winter half of the year. In Xishuangbanna in Yunnan and southern India, the high mountains and plateaus in the north block the cold air from invading southward, so the temperature is relatively high in the winter half of the year.

2. The dry and rainy season is obvious, and the precipitation is concentrated in the rainy season, and the amount of precipitation is large. Under the control of the dry northeast monsoon, precipitation is scarce in winter, and the temperature is the coolest time of the year, and the average humidity usually falls between 50 and 75%, which is the dry and dry season. In the summer half of the year, as the sun has begun to heat up in the northern hemisphere, it is the hottest half of the year, after the arrival of the southwest monsoon, it is easy to generate all kinds of retention fronts, there are often tropical cyclones generated by the ocean, and thundershowers produced by thermal convection in the afternoon, the rainfall increases significantly and there are torrential rains from time to time, the average humidity at this time generally falls in the middle of 75 100%, which makes people feel humid and hot, this is the hot and humid rainy season.

3. The monsoon is significant.

The northeast monsoon, emitted by the high pressure on land during the dry season, merges into the equatorial convergence zone over the ocean. During the rainy season, the southwest monsoon from the subtropical high in the southern hemisphere joins the Tar low.

4. Tropical cyclones prevail.

Coinciding with the "summer monsoon", tropical cyclone season is from mid-May to mid-September every year. The Indian Peninsula and the Indochina Peninsula are typical and dominant regions of this climate. But the start and end times of the seasons are different between the two

The rainy season in Peninsular India is usually from June to September, and the dry season is from October to May. Later in the dry season (April to May), the weather is very hot, with highs of 40 or more. During the rainy season, there is a lot of rain and often causes flooding.

The advance and retreat of the summer monsoon affects the progress of the rain belt in the eastern part of the mainland of China Starting from April every year, the rain belt roughly moves from south to north, and retreats from north to south after September Therefore, the rainy season in the south of China is earlier than that in the north and longer than in the north The "abnormality" of the advance and retreat of the summer monsoon and the rain belt often causes drought and flood disasters If the advance is slow and lingers in the south for a long time, it will lead to "flooding in the south and drought in the north"; If the advance is rapid and the stay in the north is long, it is easy to have a situation of "flooding in the north and drought in the south".