Extreme precipitation in Shanxi, 98 West Lake flooded into Taiyuan. What is the concept of this precipitation?

The capacity of the West Lake is about 0.0 1 cubic kilometer, and the water from 98 West Lakes is poured into Taiyuan, which is about 1 cubic kilometer. Doesn't it sound painful? Then feel the most direct destructive force, as follows:

The four-level emergency response to the rainstorm is 90 hours (only 72 hours in Henan). Let's focus on it. It's autumn. Rainstorm response is rarely started in autumn, let alone for so long (I wonder if the students are exhausted).

The ground collapsed due to coal mining, and the heavy rain turned the collapsed ground into a small lake.

65438+5000 people were forced to move overnight, and the disaster area was extensive. At the same time, many lakes burst their banks.

The actual estimate is far more cruel than the report.

If you don't feel anything by looking at this picture directly, you can take Zhengzhou 72 1 rainstorm as a reference, which is about two-thirds of the rainstorm in Zhengzhou this year. You know, Zhengzhou covers an area of 7,567 square kilometers and Taiyuan covers an area of 6,988 square kilometers. That is to say, although it looks bad 1/3 on the surface, the area of Taiyuan is small, so the heavy precipitation event in Taiyuan should not be underestimated.

In fact, since 2020, China has experienced various extreme events that are rare in history. From the super violent plum blossom in the middle and lower reaches of the Yangtze River in 2020 to the rainstorm in 20021Henan. The ranking is also from 196 1 year to top 1, and once in a thousand years.

The rainstorm in Shanxi is even more puzzling. According to the truth, in the past 10 months, it should be a crisp autumn in the north, but this year, the daily precipitation in most stations in Shanxi exceeded 200 mm. I just want to say that friends who work overtime in the Meteorological Bureau, best wishes.

As for the cause of this rainstorm, from a big perspective, it is the simultaneous influence of global warming and human activities. Simply put, with global warming, the content of water vapor in the atmosphere increases, which provides sufficient water vapor for the occurrence and development of heavy rain (after all, the source of water vapor in heavy rain must be guaranteed).

In addition, affected by the epidemic situation, the reduction of aerosol content in the atmosphere (such as the reduction of automobile exhaust emissions and the reduction of particulate matter in the atmosphere) will strengthen the south wind component to a certain extent, so that water vapor can be continuously transported from the southern ocean to the north, providing water vapor for the occurrence of heavy rain in the north.

In detail, it is mainly affected by the stable circulation situation (ensuring the transport of water vapor) and the local low-level uplift (providing unstable energy).

This year's subtropical high (an important weather system for precipitation in China) is stronger to the west than in previous years and remains stable. What does this mean? It means that the atmospheric circulation situation will be maintained stably. In other words, the water vapor from the Arctic Ocean will be continuously transported to China, which provides the first condition for the formation of precipitation.

Water vapor alone is not enough, and the formation of heavy rain requires relatively strong unstable energy. However, in June 5438+10, various shear lines and convergence systems repeatedly passed through Shanxi area, which, together with the topographic effect, strengthened the air uplift and further formed convection. The formation of convection makes precipitation violent, forming instantaneous heavy precipitation, that is, rainstorm.

It is understood that this year's rainstorm in Shanxi is more than five times the historical average precipitation, which not only has a large cumulative precipitation, but also lasts for a long time. In addition, the topography of Shanxi needs to pay special attention to the secondary disasters caused by heavy rain, such as landslides and mudslides ~