A new round of large-scale heavy rainfall is approaching. How far are we from a major flood?
Since the beginning of the flood season, the information about "a new round of heavy rain in the south" seems to have started a replay mode, stimulating our audiovisual attention over and over again.
Indeed, according to statistics, there have been 21 regional heavy rains in southern my country before, "dominating" the same period in history. There are many times and the cumulative rainfall is also large. Since the beginning of the flood season, the national average rainfall has been 23% more than the same period in normal years, which is the highest for the same period since 1954. In addition, the intensity of rainfall is also very "violent". The cumulative precipitation in 155 counties (cities) across the country has exceeded the historical extreme value. Among them, the daily precipitation in 15 counties (cities) such as Guangdong Xinyi has exceeded the historical extreme value.
So, how does it compare to 1998?
We know that floods began in South China on March 21 this year, 16 days earlier than normal. Compared with the same period in 1998, the national average precipitation since the flood season this year has been 5% more than that in 1998, and there have been 6 more heavy rains. However, this year the position of the rain belt swings greatly from north to south, and the maximum duration of the heavy rain process is not as good as that of the same period in 1998. A heavy rainstorm lasted for 16 days from June 12 to 27, 1998, and the longest rainstorm so far this year lasted for 7 days. Therefore, from the current point of view, the degree of summer floods in my country this year is weaker than that in 1998.
The precipitation was so strong that the floods were also fierce, and some areas suffered severe floods. Currently, 222 rivers across the country have experienced over-warning floods, the highest number during the same period in the past five years, and 26 rivers have experienced over-warning floods (that is, floods exceeding the guaranteed water level. The guaranteed water level refers to the water level at which the embankment project can ensure its safe operation). Six rivers experienced unprecedented floods, with major rivers experiencing 23 floods. The total flood volume was 34% higher than normal.
Vigorous "now" - the Central Meteorological Observatory issued the first orange rainstorm warning this year
Affected by the low vortex system, from the 30th, the eastern part of southwest China, Jianghan, Jianghuai, Huanghuai, etc. The land ushered in a new round of heavy rainfall. Sichuan, Chongqing and southern Shaanxi became the "first stop" for this round of heavy rainfall. According to monitoring, as of 18:00 on the 30th, rainfall in eastern Sichuan, central and northern Chongqing, southeastern Shaanxi, southwestern Hubei and other places reached 50~80 mm, in Guang'an, Sichuan, Dazu, Zhongxian and Wanzhou in Chongqing, it exceeds 150 mm, and 300~402 mm in Macheng and Hong'an, Huanggang City, Hubei!
Orange rainstorm warning signal
At 18:00 on June 30, the Central Meteorological Observatory upgraded the yellow rainstorm warning to orange. This is also the first orange rainstorm warning this year! It is expected that from July 1st to July 4th, the Huaihe River Basin will experience the largest range of heavy rainfall this year! The eastern part of Southwest China, Jianghan, southern Huanghuai, Jianghuai, western Jiangnan and northern areas along the Yangtze River will be hit by heavy rains, and there will be extremely heavy rains in local areas; among them, central and northern Jiangsu and Anhui, southeastern Henan, eastern Hubei, and northwestern Hunan and other places will be hit by heavy rains. The cumulative rainfall in some areas can reach 200 to 400 mm. The above-mentioned areas are also accompanied by strong convective weather such as short-term thunderstorms and strong winds, with maximum hourly rain intensity of 60 to 90 mm.
Animated picture, the Huaihe River Basin will encounter the largest range of heavy rainfall this year (source: China Weather Network)
We know that the early precipitation has been very abundant, and the soil is already "full" , rivers and lakes are already "drinking high". The arrival of this heavy rainfall will greatly increase the risk of disasters such as flash torrents, mudslides, landslides, collapses and floods in many places, which is no different to the already severe flood and disaster prevention situation. To "add insult to injury".
In view of this, the National Defense Administration has upgraded the level 4 emergency response for flood control to level 3, and the China Meteorological Administration has also upgraded the level 4 emergency response for major meteorological disasters (heavy rain) to level 3!
A grim "future" - respond with standards to prevent "98+" floods
Since this year, climate anomalies have occurred in many places around the world, and one of the driving forces behind this is El Niño . At present, although the super strong El Niño has left, unfortunately, its "remaining power" is still there due to the lagging response of atmospheric circulation to changes in the ocean. It will still be difficult to get rid of the "shadow" of El Niño for some time to come, and the possibility of extreme weather and climate events such as heavy rains is still high. Past rules also show that after the El Niño phenomenon ends, there is often more precipitation in the middle and lower reaches of the Yangtze River that year, making it more likely that major floods will occur.
According to the forecast of the National Climate Center, from July to August this year, precipitation may be excessive in the Jianghuai, Jianghan, eastern Southwest, Huanghuai, southeastern North China, and southern Northeast China. The middle and lower reaches of the Yangtze River, Huaihe River, etc. Heavy rains and floods may occur in the basin, the lower reaches of the Yellow River and the Liaohe River basin, and the average intensity of typhoons affecting my country in the second half of the year is relatively strong.
The catastrophic flood disaster in 1998 should still be fresh in everyone's memory. Catastrophic floods occurred in the Yangtze River, Nen River, Songhua River and other river basins, with wide impact, long duration and severe flood disaster. 1998 was the year after the strongest El Niño event in the 20th century, and 2016 was the year after the strongest El Niño event since 1951. The climate backgrounds of the two are similar. In addition, the past year 2015 was the hottest year in the world since 1880. The background of more significant global warming has significantly increased the risk of extreme weather and climate events such as heavy rains during this year's main flood season. It has also increased the uncertainty of climate predictions. Difficulty.
The scene of flood fighting in 1998 (source: China Meteorological News)
Therefore, the National Defense Headquarters has repeatedly emphasized that "the possibility of major floods this year is very high" and "prevention" should be used 98+" Yangtze River catastrophic flood as the goal. Of course, after the 1998 flood, our country's water conservancy and other infrastructure construction has been greatly strengthened, and the "skills" in preventing floods in all aspects have also been greatly improved. But despite this, we still need to be fully prepared for flooding. After all, only by being prepared can you be safe.
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