Rainstroms are usually caused by mesoscale weather systems. Normally three conditions are required for a rainstorm to form: a sufficient water vapor supply, strong vertical rising conditions, and a certain duration of precipitation. The rainy season in North China occurs from July to August every year. This year, the combination of twin typhoons with the abundant water vapor supply chain outside the Subtropical High, coupled with the stagnation of the subtropical high and the terrain, has led to heavy rains in North China. Eventually it led to mountain mudslides, landslides and other flood disasters and urban waterlogging.

In this round of rainstorms, the generation and development of double typhoons will be potentially affected by El Nino, but the impact mechanism will need to await the specific analysis of scientists after this rainstorm. Under the background of climate change, the frequency of El Nino has been greatly increased in the past 30 years compared with the past few centuries. And its climate impact will be significantly enhanced, which may cause greater climate disasters in the future.

To explain the reason for the frequency of extreme catastrophic weather, such as extreme rainstorms, should be viewed from two perspectives: climate change and human activities affecting the atmospheric environment. On the one hand, global warming not only changes the temperature state and distribution pattern of the earth’s land atmosphere, but also affects the thermal state of the ocean, which leads to the intensification of climate change, breaks the stability of the original weather and climate patterns, and leads to the frequent and frequent occurrence of abnormal weather such as extreme rainstorms. On the other hand, the aerosol caused by human activities and air pollution emissions plays a certain role in the change of precipitation pattern.

The formation mechanism of rainstorm has not been thoroughly studied so far due to the rainstorm has local features and characters, paroxysm, and changeable activity etc. Therefore, it is still a difficult problem in the field of meteorology all over the world. It is even more difficult to forecast extreme rainfall of more than 200 mm in an hour.

Around the world, the accuracy of rainstorm prediction is not high enough, with the highest accuracy in the United States at only 25%. China mainly uses numerical weather forecast model products combined with the knowledge and experience of forecasters. Compared with the European centre and the United States, China’s numerical forecasting started late, and the congenital conditions are in a weak position.

GRAPES numerical weather prediction system developed by our country has realized quasi-service operation. The relevant test shows that the system is basically correct in the rain belt forecast, which will also bring dawn to the rainstorm forecast in China.

中文原文

Translated by Shangu（Jointing.Media）

Edited by Khurram

Ralated: