Why is most of China drought?

Analysis of the causes of drought in the middle and lower reaches of the Yangtze River in 2011.

The monsoon system anomalies are the main causes: abnormal atmospheric circulation, insufficient water vapor, and strong cold air.

The Yangtze River Basin in China is a significant area of East Asian monsoon activity, and the interannual precipitation variability is large. Through preliminary analysis, experts believe that the main causes of the drought are as follows:

First, the atmospheric circulation system affecting eastern China is extremely significant. At present, the location of the western Pacific subtropical high is more northerly and stronger than the climatological average, and the western ridge is westerly. There is an anticyclonic anomaly circulation in the middle and lower troposphere, which is conducive to the occurrence of no precipitation and low precipitation for a long time, resulting in drought conditions.

Different from this year, due to the influence of the subtropical circulation system in the south of the Yangtze River in previous years, there will be a long period of spring rain in spring, which is not conducive to the occurrence of drought in the region.

Second, the water vapor transport conditions are insufficient, and the water vapor channel cannot be effectively established. China is a country with significant monsoons, during the transition between spring and summer, with the development of the tropical convection system and the outbreak of the South China Sea summer monsoon, there are usually three channels of water vapor affecting China, namely the southwesterly airflow of the Somali equatorial airflow, the southwesterly airflow of the equatorial airflow south of the Bay of Bengal and the southwesterly airflow from the south side of the subtropical high near the South China Sea and its east, but the water vapor transport in the three channels is generally weak. According to the analysis and diagnosis of the troposphere water vapor budget in the arid region of the middle and lower reaches of the Yangtze River, the region lost a lot of water vapor in May, so there was a lack of material conditions for precipitation.

Water vapor conditions are insufficient to form effective precipitation.

Third, since the beginning of this year, the cold air activity has been significant and powerful, and it is impossible to form a situation of cold and warm convergence in the middle and lower reaches of the Yangtze River. This year, the cold air in China is extremely active, and there is constantly cold air from north to east and south. The results of the cold air monitoring of the National Climate Center show that the cold air affecting the eastern part of China from January to April this year is of the national type, and its power is strong, which is not conducive to the northward advancement of the tropical system, so it has not been able to form effective precipitation in the middle and lower reaches of the Yangtze River.

To be honest, there are more hydropower stations! The construction of hydropower stations has blocked the river, so that the ecological balance is destroyed, the butterfly effect is generated, and the great changes caused by the change of small things, the Three Gorges is one of the causes of drought, in any case, the destruction of the ecological balance is caused by human beings themselves, human beings think that they have the power to transform nature, but they don't know, human beings are small in front of the power of nature!

The main reason for this year's drought is that the rainy season last very short in the Yangtze River basin due to the severe lack of precipitation due to the abnormal plum rain and typhoons, and in July and August, the typhoons did not enter the land, so there will be no significant precipitation, and it is precisely for this reason that we have drought scenarios in many areas.

The Yangtze River basin is one of the most important water systems in China, the third largest river basin in the world, with an area of 1.8 million square kilometers, but this year, because the precipitation in the Yangtze River basin has been lower than the same period since July, the weather that led to high temperature lasted for a long time, and these situations are caused by abnormal atmospheric circulation, this year's beauty season is very short, and typhoons in July and August did not enter the mainland, which led to a sharp decrease in rainfall. The decrease in rainfall has led to not only high temperature weather in many areas, There has also been a decline in waters, such as Dongting Lake in Hunan, which has even experienced most of the drought.

There is also the precipitation in the Yangtze River basin decreased by nearly 40% compared with the same period of the same year, and the rainfall in some areas was directly reduced by 50% 70%, and the number of days without effective rainfall in some areas exceeded 70 days, it can be said that it is precisely because of these reasons that the high temperature weather in most parts of the Yangtze River exceeded 50 days, and there was a very dry phenomenon, and after the drought, the water level continued to decline, which led to many relics that were previously swallowed by water gradually revealed, which is definitely not a good sign. This means that our weather can seriously affect the growth of crops.

Through the above content, we can roughly know that the impact of this hot weather on us is very large, resulting in the continuous loss of water in many areas, but it is at this critical moment that we must work together to overcome such difficulties, and each of us must save water as much as possible, save energy and reduce emissions to protect the environment.

The largest freshwater lake, Poyang Lake, is dry, and you don't even say who you are.

The more serious drought in China is in the northwest region, southwest China, Xinjiang, Gansu, Yunnan and other places.

The arid areas of Northwest China include Xinjiang, Qinghai, Gansu, Ningxia and the north of the Qinling Mountains in Shaanxi, the western part of Inner Mongolia and the western part of Shanxi, accounting for more than one-third of the total area of the country. Yunnan in southwest China is severely drought, such as Chuxiong Yi Autonomous Prefecture in Yunnan Province, which has suffered from a three-year drought that has led to a serious shortage of water storage in reservoirs. At the beginning of this year, the rainfall continued to be low, and as the temperature continued to rise, the water storage in the reservoir pond continued to decline, and the drought intensified in various places.

The diurnal and annual temperature ranges are large, and the evaporation may be much greater than the precipitation, and there will be more wind and sand, less clouds, and strong sunshine. Insufficient water is a major factor that restricts plant growth. Due to the abundance of heat, it is possible to become a high-yield area when fertilized with irrigation water supply.

(1) Meteorological reasons: Meteorological conditions such as no precipitation for a long time or low precipitation are the main factors causing drought and drought.

2) Topographic and geomorphological reasons: Topographic and geomorphological conditions are important causes of regional drought.

3) Insufficient water source conditions and drought resistance: Drought is also closely related to poor water source conditions caused by insufficient water conservancy engineering facilities, such as reservoirs and wells. ）

4) Population factors: Due to the continuous population growth and the rapid development of local social economy, the water used for life and production continues to increase, resulting in the overexploitation of water resources in some areas, exceeding the carrying capacity of local water resources, and drought is often aggravated when drought occurs.

5) Low effective utilization rate of water resources: Due to the high precipitation and low water shortage in ordinary years in southwest China, there is a significant gap between the effective utilization rate of agricultural water, industrial water and domestic water compared with the perennial water shortage areas in China, which is also unfavorable to coping with drought.

Up to now, the summer has passed, and the hot weather has gradually decreased, and I believe that the next days will be smooth and rainy.

The drought and lack of rainfall in the country and even the world are affected by global warming and the El Niño phenomenon, and the continuous high temperature has led to the evaporation of water resources, and the small rivers that used to flow and the reservoirs that were full of water are now dry.

With the rapid growth of the population and the continuous expansion of the scale of production, the increase in the use of water for enterprises and labor, and the increase in agricultural water, the groundwater level has fallen, and now it takes 40 depths to drill wells in our local area to see water.

Anthropogenic damage to the environment has resulted in a reduction in vegetation and a weakening of the soil's ability to store water. Man-made pollution of water resources, waste of water resources, and cause a shortage of groundwater resources.

In short, drought is not the cause of one aspect, it is caused by many factors, I hope we can pay attention to it, improve the environment, protect the environment, and reduce the waste of water resources.