China Weather Network News From July to August this year, the rainfall in the Yangtze River Basin was significantly less, and Sichuan, Chongqing, Jiangxi and other places encountered persistent extreme high temperature weather.
Affected by high temperature and little rain, the drought situation in the Yangtze River Basin has developed rapidly. At present, the area of extreme drought has reached 89,000 square kilometers, which has caused obvious impact on agricultural production and power supply.
What impact has the meteorological drought in the Yangtze River Basin brought to the local area?
It is the flood season but shouts "thirsty", who is the driving force behind the scenes?
When will the weather change?
1. How serious is the water shortage and drought in the Yangtze River Basin?
From July to August this year, the rainfall in the Yangtze River Basin was significantly less. The average rainfall in July reached 141.2 mm, which was 48.2% lower than the same period of the previous year and the lowest in the same period in history since 1961.
Since August, the accumulated precipitation in Jiangnan, Jianghan, and the eastern part of the southwest region has been less than 10 mm.
Monitoring data from the Central Meteorological Observatory shows that from July 1 to August 15 this year, the accumulated precipitation in major cities in the Yangtze River Basin was at least 50% lower than the same period of the previous year. Among them, Nanchang, Fuling, Wulong and other places were more than 80% lower. The rainfall in the same period of the year is generally above 200 mm, but this year it is only 30 to 40 mm.
In addition to the significantly less rainfall, the abnormally long-lasting high-intensity high temperature also made the meteorological drought develop rapidly.
Up to now, the area of moderate drought and above in the Yangtze River basin has reached 1.267 million square kilometers, of which 89,000 square kilometers are extremely dry.
Sichuan, Chongqing, Hubei, Jiangxi and other provinces (cities) have experienced drought conditions above severe.
2. What impact does high temperature and drought have on people's production and life?
The water level of rivers has dropped, the area of lakes has shrunk, and even entered the dry season ahead of schedule. Many arable lands have been affected by drought, and water supply and power supply are in short supply. The high temperature and drought have had a significant impact on the production and life of local people.
According to the Ministry of Water Resources, affected by the weather with high temperature and little rainfall, the water levels of the main stream of the Yangtze River and Dongting Lake and Poyang Lake are currently 4.85 to 6.13 meters lower than the same period of the previous year. The area has shrunk by three-quarters from June.
Among them, on August 4, the water level of Poyang Lake was lower than the dry water level, setting a record for the earliest dry water period since records began in 1951.
The 6 provinces (cities) of Sichuan, Chongqing, Hubei, Hunan, Jiangxi and Anhui affected 12.32 million mu of arable land, and 830,000 people and 160,000 large livestock were affected by the drought.
In some areas that rely on water to generate electricity, there is a power shortage.
According to the Economic Information Network, Zhou Jian, deputy chief engineer of the State Grid Sichuan Electric Power Control Center, said that 80% of the local electricity supply comes from hydropower. The rare high temperature and drought disaster this year has caused serious shortage of water in major river basins, resulting in hydropower generation in the province. Ability decreased by more than 50%.
Dazhou and other places have introduced orderly power curtailment policies, which have eased the power shortage.
3. The Yangtze River Basin is relatively abundant in water resources and is currently in the flood season. Why is there such a severe drought?
According to Wang Weiyue, a meteorological analyst at China Weather Network, this is related to the "super-long standby" mode of high temperature and low rainfall in this area from July to August this year.
This year, the intensity of the subtropical high is obviously stronger, and it has controlled the Sichuan Basin to Jianghan, Jiangnan, Jianghuai and other regions for a long time.
Under its control, sinking airflow prevails in the above-mentioned areas, which causes the ground to warm up, and it is not easy for the sky to form clouds, making it easier for solar radiation to reach the ground, and the high temperature is frequent and strong.
This year, the intensity of the subtropical high pressure is relatively strong, resulting in continuous high temperature and little rainfall in the entire Yangtze River Basin. The main rivers and lakes in the basin have significantly less water, and the water level is significantly lower, resulting in obvious drought.
4. When will the high temperature in the south ease and when will the rain come?
In the coming week, the subtropical high will still be entrenched in Jiangnan and South China, and the intensity will be strong, and the weather pattern of high temperature and little rainfall will remain.
Wang Weiyue introduced that starting from the 25th, as the cold air in the north strengthens and moves southward, infiltrating from the bottom layer of the subtropical high, the high temperature weather in the south will weaken, and precipitation may occur.
There will be moderate to heavy rain and local heavy rain in the southwest, central Jiangnan and southern China.
Under the dual influence of rainfall and cold air, the intensity of the prolonged high temperature weather in the south has weakened.
The range of 40°C in the Yangtze River Basin has been reduced. For example, Shapingba in Chongqing has reached 40°C+ for 11 consecutive days, and the highest temperature is expected to drop below 40°C around the 26th.
However, there are still high temperatures above 35°C in many places in the Yangtze River Basin, and heatstroke prevention work cannot be relaxed.
(Text / Jiang Yi data support / Wang Weiyue)