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https://news.sina.com.cn/c/2020-07-14/doc-iivhvpwx5199732.shtml
The average rainfall in the Yangtze River Basin exceeded the same period in 1998
July 14, 2020 01:28 Beijing News
Original title: The average rainfall in the Yangtze River Basin exceeded the same period in 1998
Since June this year, there have been 433 rivers with over-alarm floods in total, of which 109 rivers have over-protected floods and 33 rivers have over-historic floods. The No. 1 flood occurred in the Yangtze River, the upper reaches of the Yellow River, the Xijiang and Beijiang Rivers, and the Taihu Lake in the Pearl River Basin. From June 2 to July 12, at 6 o'clock, the Central Meteorological Observatory issued a rainstorm warning for 40 consecutive days, becoming the longest time since the rainstorm warning business was launched in 2007.
How was the disaster this year? What are the characteristics of the flood situation compared with 1998? On July 13th, the State Council Office held a regular briefing on the State Council’s policies. The Secretary-General of the National Disaster Reduction Committee, Deputy Minister of Emergency Management Zheng Guoguang, Deputy Minister of Water Resources Ye Jianchun and other relevant ministries and commissions introduced the situation of flood control and drought relief and responded to reporters. ask.
In addition, the China Meteorological Administration organized experts such as Ma Xueke, chief forecaster of the Central Meteorological Observatory, Wang Yongguang, chief forecaster of the National Climate Center, Huang Lei, a researcher of the Climate Change Adaptation Office of the National Climate Center, and Zhai Jianqing, an associate researcher of the National Climate Center. The rain is fierce.
1 What are the characteristics of the flood situation this year?
is mainly reflected in the four aspects of rainfall concentration and flood concentration
Deputy Minister of Water Resources Ye Jianchun introduced that the characteristics of the flood situation this year are mainly reflected in four aspects:
Rainfall is concentrated. Since June, heavy rainfall has been concentrated in the Yangtze River, Taihu Lake and other river basins, and the cumulative rainfall has averaged 50% to 1.6 times more than normal. Especially in Wuyuan, Jiangxi, rainfall reaches 1966 millimeters. "The average annual rainfall in Beijing is 630 millimeters. Wuyuan has been raining in Beijing for three years since June."
Flood concentration. Since June this year, No. 1 floods have occurred in the Xijiang and Beijiang rivers of the Pearl River, the upper reaches of the Yellow River, the Yangtze River and Taihu Lake. There are 433 super-alarms in the country, accounting for 96% of this year. Among the 433 rivers, there are 422 in the south, except for a few in the Yellow River and other river basins, the others are in the south. Time is mainly concentrated since June, and most of the space is in the south.
The floods of the Yangtze River and Taihu Lake were concurrent. At present, there are over-alarms across the Yangtze River's main stream under supervision. Over-protection floods have also occurred in the middle Dongting Lake. Over-alarms have also occurred in Taihu Lake. The water level is close to 4.45 meters. According to the forecast, it will continue to rise. It may even exceed 4.65 meters. 4.65 meters is Taihu Lake. Guaranteed water level.
The floods in small and medium-sized rivers are frequent and repeated. Among the small and medium-sized rivers, there are 397 super-alarms, 100 of which are over-guaranteed, a high proportion, and 27 exceed the highest water level in history.
2 What happened to the disaster caused by heavy rainfall?
Twenty-seven provinces (autonomous regions and municipalities) suffered 37.89 million disasters
The reporter learned from the Ministry of Water Resources that there are currently 433 rivers with over-alarm floods, including 109 rivers with over-protection floods and 33 rivers with over-history floods. The No. 1 flood occurred in the upper reaches of the Yangtze River, the Yellow River, the Xijiang, Beijiang and Taihu Lakes of the Pearl River Basin. At present, the water level below the Jianli River and the Dongting Lake, Poyang Lake and Taihu Lake are still in super-alarm status. The rest of the rivers and rivers have stable water conditions.
Zheng Guoguang, Secretary-General of the National Disaster Reduction Committee and Deputy Minister of Emergency Management Department introduced that this year my country has a large total rainfall and local intensity. Since June, 38.789 million people in 27 provinces (autonomous regions and municipalities) have been affected, and 141 people have been killed or missing.
According to the national water regime information on July 12, the water levels of 10 hydrological stations in the main stream of the Yangtze River exceeded the alarm level, and the water levels of Poyang Lake and Dongting Lake exceeded the alarm level. All the hydrological stations in Poyang Lake, the most important water area in Jiangxi and the largest freshwater lake in the country, exceeded all alarms. At least four hydrological stations in Poyang Lake, such as Kangshan Station, Xingzi Station, Tangyin Station and Raohe Poyang Station, exceeded the historical flood level in 1998. In the Taihu Lake Basin, as of the 12th, the Taihu Lake water level exceeded the warning water level for the 15th consecutive day.
3 How is the flood situation in the next few days?
14 to 16 days of the Yangtze River Basin reproduced a large range of heavy rainfall
According to the Central Meteorological Observatory's July 13th news, from July 14th to 16th, the Yangtze River Basin will once again experience large-scale heavy rainfall, and heavy rains will occur in Sichuan, Chongqing, Shaanxi, Hubei, Anhui, Jiangsu, Zhejiang and Shanghai.
The five consecutive heavy rains that occurred after mid-June were concentrated in the southwestern region to the middle and lower reaches of the Yangtze River. From July 14th to 16th, the Yangtze River Basin will once again experience large-scale heavy rainfall, with a high degree of overlap between the heavy rainfall falling area and the previous period. In the northeastern and southern parts of the Sichuan Basin, northern Chongqing, southeastern Shaanxi, northeastern Hubei, southeastern Henan, central and southern Anhui, southern Jiangsu, Shanghai, northern Zhejiang and other regions, the cumulative rainfall is 100-180 mm. Up to 200~300 mm.
From June 1st to July 13th, most of the surface rainfall in the main stream of the middle and lower reaches of the Yangtze River Basin was greater than 500 mm, and the surface rainfall in the Hankou to Jiujiang River Basin exceeded 800 mm, more than the same period in 1998. It is estimated that from July 14 to 16, most of the main stream of the middle and lower reaches of the Yangtze River will have 50 to 100 millimeters of surface rainfall, and the upper reaches of the Yangtze River will reach 40 to 60 millimeters of rainfall from Yibin to Yichang.
4 How does the recent rain situation compare with the same period in 1998?
The average rainfall in the Yangtze River Basin is the highest since 1961
Since June 1, there have been six heavy rainfalls in the south. As of July 12, the average rainfall in the Yangtze River Basin reached 403 millimeters, 49% more than the same period in normal years, and exceeded 2016 (395 millimeters) and 1998 (358 Mm) became the most in the same period since 1961 with complete meteorological data.
Ye Jianchun introduced that at present, the water level of some stations of Poyang Lake exceeds 1998, and the water level of the main control stations of the middle and lower reaches of the Yangtze River is lower than 1998.
Zheng Guoguang said that the current rain situation cannot be simply compared with 1998. In 1998, after the rain belt was lifted to the north, it returned to the middle and lower reaches of the Yangtze River and continued until the end of August. It lasted for a very long time. The Yangtze River embankment was soaked in water for a long time, and the rescue efforts were very strong. At present, the domestic flood control and dispatching capabilities are much stronger than in 1998, and the National Defense General's command and dispatching mechanism has gradually been improved. Therefore, compared with 1998, our country's ability to defend against floods is now stronger. From a meteorological point of view, it is unlikely that there will be two months of concentrated precipitation similar to 1998.
Zhai Jianqing said that considering the scope, duration and rainfall, it was found that since June 27 (as of July 9), the comprehensive intensity of the regional rainstorm weather process in southern my country was the fifth strongest since 1961 (first in 1998). Compared with the 1998 flood, the southern regional heavy rain weather process from June 27 to July 9 this year has the characteristics of long duration and wide range of influence.
5 How to deal with the breakthrough of the water level of Poyang Lake?
1000 fire rescue commanders supported the flood control in key areas such as Poyang Lake
According to the client's news of the People's Daily, in response to the current severe flood control situation, the State Defense General Administration decided to send six more ministerial-level working groups to be led by comrades from the ministries and commissions of the Ministry of Public Security, the Ministry of Natural Resources, the Ministry of Water Resources, the Emergency Management Department, and the China Meteorological Administration. The team went to seven key areas including Jiangxi, Anhui, Hunan, Hubei, Jiangsu, Zhejiang and Chongqing to guide the inspection of flood prevention and relief work.
According to the severe flood situation of Poyang Lake in Jiangxi Province, the Emergency Management Department urgently dispatched 1,000 professional fire rescue commanders in the vicinity of flood relief, water rescue, geological disaster rescue, etc., and quickly assembled to support flood relief in key areas such as Poyang Lake.
Zheng Guoguang said that as of the 12th, Jiangxi Province had invested 70,500 people in flood relief and rescue work, and the average number of embankment patrols per kilometer was 29.
6 What is the focus of the next stage of flood control?
Continue to do a good job in flood control of southern rivers
Ye Jianchun introduced that my country will soon enter the “seven times and eight times” (late July to early August) critical period of flood control. It is expected that large regional floods are likely to occur in the middle reaches of the Yellow River, the Haihe South System, the Songhua River, the Liaohe River, the Yangtze River, the Huaihe River, and the Taihu Lake. The water levels in the Yangtze River and Taihu Lake are now relatively high and may continue for some time. It is expected that the rain belt will be lifted to the north in the later period, and regional floods may occur in the northern rivers. Therefore, in the next step, while the flood prevention of the southern rivers will continue, the flood prevention preparations in the northern regions will be strengthened.
Northern China should also focus on the "three major risks" of excessive floods, reservoir accidents and flash floods. "There have been no floods in these basins in the north for many years. The awareness of flood control and the project's ability are relatively low and weak. Therefore, the north needs to focus more closely." Ye Jianchun said.
7 How strong is the recent southern heavy rain?
Daily rainfall in many places broke through historical extremes
According to the statistics of the National Climate Center, since the flood season, as of July 10, there have been 15 large-scale heavy rainfall processes in southern my country. Among them, from June 11 to July 10, the main rain belt northwards to the middle and lower reaches of the Yangtze River, the rainy center is located in northern Hunan, northwestern Jiangxi, eastern Hubei, southern Anhui, central Zhejiang and other places, Zhejiang, Anhui, Jiangxi Bureau The cumulative precipitation in the area exceeds 800 mm.
Daily rainfall in many places broke through historical extremes. For example, during the heavy rainfall from July 4th to 10th, the daily rainfall of Huangmei, Xishui, Hubei, Ji'an, Xiajiang, and Longhui, Hunan, and other national meteorological observatories broke through extreme values.
From June 1st to July 9th, Hubei, Anhui, Jiangsu, Guizhou, Zhejiang, Chongqing, Hunan, Jiangxi, Shanghai, Guangxi, Sichuan and other provinces totaled 85 stations with cumulative precipitation exceeding half of the annual precipitation.
The heavy rain brought pressure on the flood control of the Yangtze River Basin. From June 1 to July 9, the average precipitation in the Yangtze River Basin reached 369.9 millimeters, 54.8 millimeters more than the same period in 1998. It is the history since 1961 (with complete meteorological observation data) The most during the same period.
8 Why did the southern rain fall into the "wheel war"?
Mainly related to the situation of atmospheric circulation since June this year
Since June, there have been frequent heavy rainfalls in the southern region. Not only are there many heavy rainfall processes, but the heavy rainfall is round after round, with a very short interval.
Ma Xue explained that this is mainly related to the atmospheric circulation situation since June this year.
The Northwest Pacific Subtropical High (subtropical high for short), which has a huge impact on my country, is a stable and less dynamic warm deep weather system. The southwestern airflow on the northwest side of the periphery is just an important channel to transport water vapor to the rainstorm area.
Specifically, since June this year, the subtropical high has been stronger than in the same period of previous years. The southwestern airflow around its periphery transports abundant water vapor from the Bay of Bengal or the southern sea area of China to southern China. At the same time, the cold air activity in the north is also relatively frequent, causing The situation where cold and warm air continue to converge in the southern region has resulted, resulting in frequent and continuous heavy rainfall.
9 Is it possible that continuous heavy precipitation is abnormal climate?
The early entry of Mei and the strong Meiyu front are the reasons for the abnormal rainfall in the Meiyu season in the middle and lower reaches of the Yangtze River
In recent years, extreme weather and climate events have been increasing, and the climate seems to be more and more abnormal. Is the abnormal climate behind the continuous heavy precipitation?
Wang Yongguang introduced that it was Meiyu, a "monster", that triggered the heavy precipitation process. Specifically, the early entry into Meihe and the strong Meiyu front are the reasons for the abnormally high rainfall during the Meihong season in the middle and lower reaches of the Yangtze River.
This year, Meiyu in the Jiangnan region was 7 days earlier than in previous years, and Meiyu's "main battlefield", the middle and lower reaches of the Yangtze River, had already entered Meimei on June 9. It turned out that the onset of the South China Sea summer monsoon was earlier this year, and the location of the ridge line of the Western Pacific Subtropical High in the middle and early June was north, which together led to the early entry of plums in the middle and lower reaches of the Yangtze River.
In addition, this "monster" also obtains energy from other places, causing Mei Yufeng to be strong. A weak El Ni?o event occurred in the autumn of 2019, and the temperature of the North Indian Ocean was abnormally warm, resulting in a significantly stronger secondary high.
At the same time, the meridional circulation at middle and high latitudes developed and cold vortices were active. The cold air exploded on the way to the middle and lower reaches of the Yangtze River. As a result, the cold and warm air converged in the middle and lower reaches of the Yangtze River, which caused the Meiyu front to be stronger and the precipitation in the middle and lower reaches of the Yangtze River to be significantly higher.
10 Rainband movement reduces flood control pressure?
The pressure of flood control in the Yangtze River Basin will not be reduced
Since July, my country's main rain belt has been maintained from the east of the southwest to the middle and lower reaches of the Yangtze River. From July 11 to 12, the main rain belt lifted northward in stages.
After a short intermittent period, according to the Central Meteorological Observatory forecast, from July 13 to 16, the main rain belt will fall south to the middle and lower reaches of the Yangtze River. During this period, the main areas of heavy rainfall will appear in the middle and lower reaches of the Yangtze River, and some areas in eastern Chongqing, northern Guizhou, Hubei, northern Hunan, northwestern Jiangxi, central and southern Anhui, southern Jiangsu, Shanghai, northern Zhejiang, etc. To the rainstorm, the local heavy rainstorm.
Ma School reminds that this has a great degree of coincidence with the heavy rain on the 4th to 7th, and it is necessary to pay attention to the superimposed impact of precipitation.
Even if the eastern part of the rain belt rises north in mid-to-late July, the pressure for flood control in the Yangtze River Basin will not be reduced. The obvious precipitation in the middle and upper reaches of the Yangtze River will still pose a threat to rivers and lakes with high water levels.
11 Will there be more extreme climate events?
If greenhouse gas emissions are not controlled, it will increase in the future
The climate change assessment report issued by the United Nations Intergovernmental Panel on Climate Change (IPCC) pointed out that there will be more high-temperature and heavy rain events in some parts of the world in the 21st century, and the degree of drought will increase, threatening the food, water and energy security of countries.
Huang Lei introduced that although it is currently difficult to attribute a single weather and climate event (such as the southern rainstorm) directly to global warming, under the background of global warming, some extreme weather and climate events are indeed increasing.
In fact, under the background of global warming, since 1951, my country's average temperature and extreme temperature have shown a significant upward trend, and some extreme weather and climate events show the characteristics of stronger intensity, more frequent occurrence, and longer duration.
The prediction results of the climate model show that if anthropogenic greenhouse gas emissions are not controlled, the frequency, intensity and duration of some extreme events in the world will increase significantly. By the end of the 21st century, the probability of high temperature heat wave events in land areas will be 5 -10 times, the frequency of extreme heavy precipitation events will also increase in most parts of the world.
Therefore, it is urgent to further enhance China's ability to respond to extreme disasters. It is necessary to take extreme disaster response as the core content of adapting to climate change, strengthen risk prevention measures for extreme disasters, strengthen monitoring and early warning of extreme weather and climate events, and manage meteorological disaster risk, and carry out key regions 1. Impact assessment of climate change in key industries, strengthening ecological and environmental meteorological services, and improving government-led, department-linked, and socially involved disaster prevention and mitigation mechanisms.
Number theory
4206 square kilometers
Yesterday, China Meteorological Administration reported that the area of the main body of Poyang Lake and the surrounding waters increased rapidly due to the continuous impact of heavy rainfall and upstream water. Satellite monitoring shows that at 18:00 on July 8, the main body of Poyang Lake and the surrounding water area reached 4,206 square kilometers, the largest in the past 10 years.
185 seats
The reporter learned yesterday from the Jiangxi Provincial Flood Control News Ventilation Conference that as of the evening of July 12, the 185 drainage facilities in Poyang Lake District had single diversion polders (available for agriculture at low water levels and flood storage at high water levels). In floods, the remaining 32 single-retreat dikes were all opened yesterday, and flood gates were opened to store flood water. After analysis, the water level in the lake area can be reduced by 25-30 cm.
2278 people
The General Administration of State Defense has specified 2,278 people in charge of flood control and drought relief at various local levels and made them public.
