2. Rainwater can irrigate crops, which is beneficial to afforestation.
Rain can reduce the dust in the air and lower the temperature.
4. Rainwater is beneficial to reservoir water storage, groundwater recharge and river water replenishment, and is beneficial to power generation and shipping.
5. Rainwater can wash away ground garbage, dilute toxic substances and purify the environment.
Extended information The continuous rainfall in the south is related to El Nino.
According to the latest monitoring by the National Climate Center of China Meteorological Bureau, as of February 20 19, the range, intensity and duration of SST warming in the equatorial Middle East and Pacific Ocean have reached the standard of forming an El Ni? o event. Although the El Ni? o event is weak, it has a significant impact on the tropical and subtropical regions of the world.
Experts such as Ding, academician of China Academy of Engineering and special adviser of China Meteorological Bureau on climate change, pointed out that persistent rainy weather in southern China is related to El Nino.
Climate experts pointed out that El Nino refers to a natural phenomenon that the SST in the equator, the Middle East and the Pacific Ocean is abnormally high, thus affecting the atmospheric circulation. Since June last year, the warmer sea surface temperature in the equatorial Middle East Pacific has gradually expanded, and it entered the El Ni? o state in September.
In this El Nino event, the SST in the equatorial central Pacific is generally higher than that in the equatorial eastern Pacific. This SST situation causes the subtropical high in the western Pacific to be stronger, westward and northward than normal, which is beneficial to guide a large amount of water vapor at low latitudes to China.
At the same time, cold air activities are frequent and strong in the middle and high latitudes in winter, and cold and warm air flows mainly meet in Jianghuai to Jiangnan, which leads to obviously more precipitation and continuous rainy weather.
Ding pointed out that El Nino is a natural phenomenon and the product of the synergy between the ocean and the atmosphere. There is an El Nino event every two to seven years in the world. El Nino mainly occurs in the equatorial Middle East and the Pacific Ocean, but its influence has spread all over the world. "Generally speaking, after El Ni? o, almost all the weather and climate in the world will be abnormal to varying degrees."
According to the climate monitoring data, although El Nino, which began to appear in September last year, was weak, the atmospheric response to sea surface temperature changes was extremely rapid, exceeding previous years. Since the winter of last year, the weather and climate phenomena caused by El Nino have appeared constantly, and almost all climate models in the world have given the prediction conclusion that "this winter is warm".
From 1 in February last year to 1 on February 22 this year, there were 40 to 55 days of precipitation in many areas in the south, which was more than normal 10 to 15 days. The average precipitation days in Guizhou, Hunan, Hubei, Jiangxi, Zhejiang, Anhui and Jiangsu provinces are 190. The sunshine hours in southern Jianghuai, Jianghan and Jiangnan are 50% to 80% less than normal.
Ding introduced that in the past, this persistent precipitation anomaly in the Yangtze River basin, which should have occurred in summer, appeared in winter in advance, which was called "summer in winter", that is, the atmospheric circulation and persistent rainfall in rainy summer appeared in winter. This is one of the southern meteorological disasters mainly studied by meteorologists in China in the 1960s and 1970s. After the obvious warming in the 1980s, such disasters were greatly reduced, but they still existed.
Baidu encyclopedia-rain
People's Daily Online-Continuous rain in the south is related to El Nino.