Rescuers evacuate stranded people in flood water in Quannan County, East China's Jiangxi province on June 13, 2022. [Photo/Xinhua]

La Nina, fluctuating weather conditions contribute to excessive rain seen in south

Global warming, La Nina and a fluctuating northeast cold vortex are all contributing to more severe climatic conditions across China this year, and from July to August, fluctuations in weather conditions will cause periodic droughts and floods, according to the China Meteorological Administration.

Rain will hit most parts of the country, except the Xinjiang Uygur autonomous region, and some areas in Northwest, East and Central China that may experience more periodic droughts and heat waves than normal, said Yu Yong, deputy head of the China Meteorological Administration.

Since the start of flood season on March 17, there has been more rain in the south than in the north of the country.

Precipitation in the Pearl River basin for the period has broken the historical record.

Data from the CMA showed that from March 17, 18 regional torrential rain events occurred in China with 17 of them in the south. The national average precipitation was 241.5 millimeters, 11 percent higher than normal.

Guangdong and Hainan provinces and the Guangxi Zhuang autonomous region were hit the hardest.

More than 470 counties have been affected by hail, thunderstorms and strong winds, Yu said.

Rainfall caused hundreds of rivers in southern parts of China to flood. On June 15, an extremely high tide was recorded in Guangzhou, Guangdong province, causing the suspension of all passenger ship routes, according to the local authorities.

Yu said that since spring, affected by La Nina, a weather pattern stemming from cooler-than-average ocean surface temperature in the equatorial Pacific, the rainy season began earlier than normal.

Zhou Bing, chief expert of the administration's meteorological service department, said that as well as La Nina, global warming is also causing a less stable atmospheric circulation system and increased precipitation.

Especially since June, the northeast cold vortex, a major rain-bearing circulation system over northeastern China that can lead to severe convective weather in summer, has become more active and moved to the south, leading to unusually heavy rain, Zhou said.

In some parts of North and Central China, it is a different story. In Xuchang, Henan, the ground surface temperature reached as high as 70 C, causing asphalt roads to melt and break up.

The administration's data showed that moderate to severe droughts had affected land covering 857,000 square kilometers, about 9 percent of the country's total land area. The main areas affected include Henan, Hubei, Gansu and Jiangsu provinces.

Since June 13, high temperature has affected more than 600 million people, it said.

Yu said that China's climate is also affected by changes in sea temperature in other ocean areas as well as snow cover and polar ice.

"There are great uncertainties in the climate impact. Meteorological departments will keep monitoring and revising climate forecasts," Yu said.