Is the strongest rainstorm since the flood season in South China related to climate anomalies?

Today, with more and more climate anomalies, almost everyone is talking about climate change, and every time they see similar meteorological disaster information, they can always cause infinite reverie. Especially in the case of extreme rainstorm and drought, people will use climate anomalies to speculate one after another. Indeed, it is understandable to think so. After all, global warming is an indisputable fact. Although the international community has been advocating carbon neutrality and peak carbon dioxide emission in recent years, trying to delay and stop the pace of climate warming, the effect is not ideal. Only at the beginning of the globalization of the epidemic in 2020, global industrial production slowed down and carbon emissions decreased. However, with the normalization of the epidemic, carbon emissions returned to a high level, and the resulting extreme weather made more and more climate experts.

Perhaps in most people's understanding, the performance of global warming is only that the average temperature is getting higher and higher, but the actual climate warming affects the whole meteorological system and changes the fixed three-circle circulation on the earth, thus making the climate distribution more and more unstable. For example, the rainstorm in Zhengzhou last July, the extreme rainfall in Shanxi and Taklimakan Desert, the 56-degree high temperature in South Asian subcontinent such as India, and the 37-degree extreme high temperature in the Arctic Circle are all mixed with global warming.

Closer to home, the heaviest rainfall in South China since the flood season was caused by the collision between strong cold air in the north and warm and humid air at the western edge of subtropical high. Judging from the time of rainfall and the area affected by rainfall, this heavy rainfall is indeed different from previous years. Although May-June is the peak period of the first flood season in Guangdong and Guangxi almost every year, it is very normal to have heavy rain at this time. There is a local saying that "dragon boat water" often happens. The western Pacific subtropical high is a permanent high-pressure circulation system in the Pacific Ocean. During this period, the ridge line of subtropical high is just south of 20 north latitude, and the warm and humid airflow carried by the northern edge of high pressure just reaches South China.

However, the thermal intensity of this heavy rainfall was higher than that of previous years. The cyclone storm Asanni from the Indian Ocean (Bay of Bengal) just passed through Indochina Peninsula and transported a lot of water vapor to South China. In addition, in early May, the cold air force from north to south was relatively strong, and the intensity of cold and warm air was similar, which violently collided over South China and brought heavy rainfall to South China. More importantly, according to the latest forecast of the meteorological department, the third season of the South China Sea summer monsoon in May this year (the climate lasts for five days, and the third season in May refers to May 1 1- 15) is a little earlier than normal, and the La Nina event in the equatorial Middle East and the Pacific Ocean will last until 2022, with frequent and repeated global extreme weather, which makes the climate in China complex and changeable.

Finally, due to the continuous heavy rainfall, the whole Pearl River basin is affected by certain floods, especially in the eastern part of the Pearl River basin, which is at higher risk of being affected by floods and meteorological disasters, and urban waterlogging may also occur in southern cities. Fortunately, the ability to cope with floods in southern cities is generally stronger than that in the north, but attention should be paid to prevention.