Since the beginning of this year, the precipitation in the middle and lower reaches of the Yangtze River has been less, resulting in drought in some areas, the water level has continued to be low, and people's domestic water consumption, as well as agriculture, shipping, aquaculture and other aspects of production have been affected. On the 21st and 23rd, the obvious precipitation in the above areas eased the soil moisture, but failed to improve the water storage status of rivers and lakes. It is expected that the sunny weather will continue and the drought will increase.
The middle and lower reaches of the Yangtze River suffered from severe drought since 1961
According to relevant climate monitoring, from January 1 to May 20, most of the precipitation in the middle and lower reaches of the Yangtze River is 30% to 80% less than normal. The average precipitation in Anhui, Jiangsu, Hubei, Hunan, Jiangxi, Zhejiang, and Shanghai. The least for the same period since 1954.
The continuous decrease of precipitation leads to abnormally low water levels in rivers and lakes, significant reduction in water area, agricultural production, and difficulty in drinking water in some areas. According to meteorological satellite remote sensing monitoring, the control flow of the main stream of the Yangtze River is 25% to 70% less than that of normal years. On May 20, the water area of ​​Dongting Lake decreased by about 73% compared with the same period of last year.
Affected by the low precipitation, agricultural production in some areas of the middle and lower reaches of the Yangtze River is greatly affected. Taking Hubei as an example, according to the statistics of the Hubei Provincial Defense Office on the 20th, except for the Shennongjia forest area, 83 counties and cities in 16 other cities and counties are There is drought, and the area of ​​drought-affected farmland is 18.382 million mu, of which 87.84 million mu of drought in the field crops (2.34 million mu of heavy drought), 8.629 million mu of water shortage in paddy fields, and 10.12 million mu of dry land shortage; there are 780,000 and 248,000 heads. Large livestock drinking water is difficult; the water level of Danjiangkou Reservoir has dropped to 134.7 meters, which is lower than the dead water level of 4.3 meters, which is the lowest in history, and the reservoir water storage capacity is only 5.57 billion cubic meters.
Li Xiaoquan, chief expert of China Weather Network, said: "The drought in the middle and lower reaches of the Yangtze River this year is inseparable from the atmospheric circulation. This year, the subtropical high is located eastward, which makes it difficult to transport water vapor to the inland areas, and has not formed in the middle and lower reaches of the Yangtze River. Strong rainfall."
Precipitation to improve dryland crops, lyrical rivers, low water levels or affect rice transplanting
On May 21-23, a large-scale precipitation process occurred in the middle and lower reaches of the Yangtze River. Most of the precipitation was 10-50 mm, including southern Susong, central and eastern Hubei, southwestern Zhejiang, western Zhejiang, most of Jiangxi, and central and northern Hunan. The precipitation in the west is 20 to 50 mm, and in some areas it is 50 to 100 mm.
“The time distribution of the precipitation process is relatively uniform, which is conducive to the full penetration of water. The soil moisture of most farmland has been improved significantly. The drought in southern Jianghan and northern Jiangnan is obviously moderated, and the dryland area is reduced, which is conducive to the growth of dryland crops such as cotton, corn and vegetables. Mao Liuxi, director of the Agricultural Meteorological Center of the China Meteorological Administration, said, "But the increase in water storage in the reservoirs in areas with low precipitation is still very limited, and the transplanting of rice in a season requires a large area of ​​blisters, which causes transplanting to be blocked, even if it has been moved. Planted, there is no water to ensure the growth of seedlings, seedlings or dead."
In addition, with the precipitation, the temperature in most areas has decreased. From 21 to 22, the temperature of the daily temperature in the upper part of the Yangtze River and the Huai River, Jianghan and the northern part of the Yangtze River has dropped to 13 to 19 °C, which has certain adverse effects on early rice tillering and spike differentiation. Early rice tillers are slow, and short spikes and small grains appear, which affects their yield and quality.
In the future, there will be no obvious precipitation or further rise in the middle and lower reaches of the Yangtze River.
"According to the current forecast, by the end of May, there will be no obvious precipitation in the middle and lower reaches of the Yangtze River, and the future temperature will be higher. The crops need water, and the drought elephants may rise further. It should not be taken lightly." Mao Liuxi told reporters.
The Central Meteorological Observatory predicts that from mid-June to June, the middle and lower reaches of the Yangtze River will be dominated by sunny and hot weather, including southern Jiangsu, Shanghai, central and northern Zhejiang, central Anhui, southeastern Hubei, northeastern Hunan, northwestern Jiangxi, and northwest Guizhou. Precipitation in most areas is less than normal, drought may continue and develop, and insufficient water storage may affect early rice yield formation, one-season rice growth and development, late rice sowing and growth, and dryland crops such as cotton and corn.
Mao Liuxi suggested: "Water conservancy dispatch can be used against water and drought, but for agricultural drought, it is necessary to take corresponding agricultural measures to combat drought. At present, strategic measures (such as repairing reservoirs and dams) are too late. Only tactical responses can be taken, such as watering and drought relief, and well drainage. Dryland crops have been alleviated by this round of precipitation and drought, but we must also pay attention to timely protection and seek water sources to prevent drought from continuing to develop."
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