Since April, South China has ushered in many heavy precipitation processes. The monitoring of the Central Meteorological Observatory shows that since the 19th, the cumulative rainfall in Guangdong, central and eastern Guangxi, southern Hunan, southern Jiangxi, southwestern Zhejiang and other places has been 100-150 mm, 200-350 mm in central and northern Guangdong, eastern Guangxi and other places, and 400-519 mm in Zhaoqing, Qingyuan, Shaoguan, Guangzhou, Huizhou and other places in Guangdong.
A new round of rain is coming again, today (25th) is the strongest period of this round of heavy rainfall, among them, there are heavy rainstorms in some areas of central and southern Guangdong, local heavy rainfall; tomorrow the scope of heavy rainfall will be reduced, and there will still be heavy rains in some areas in eastern Guangdong and other places, and local heavy rains.
Sun Jun, chief forecaster of the Central Meteorological Observatory, analyzed that from the 27th to the 28th, there was still rain in the southern region, and there was still heavy rain or torrential rain in parts of the southern and eastern parts of the Yangtze River, northern and central and eastern parts of South China, and there were heavy rains locally. From the 29th to the 30th, there will be a round of heavy precipitation in Jianghan, Jianghuai, Jiangnan and the central and northern parts of South China.
Statistics from the National Climate Center show that precipitation in southern China since April this year has more than doubled compared with the average for the same period of the year, the second highest since 1961.
Zheng Zhihai, chief forecaster of the National Climate Center, said that there are two main reasons for this: On the one hand, under the background of global warming, the temperature in Jiangnan and South China is significantly higher than that in the same period of the year, and the increase in temperature increases the water content of the atmosphere, and at the same time enhances the intensity of convection, making heavy precipitation events more common. On the other hand, under the influence of El Niño events, the western Pacific subtropical high has continued to be strong since April, guiding abundant warm and humid airflow from the South China Sea and the Bay of Bengal to the southern part of the mainland, and cooperating with the circulation anomalies over the Qinghai-Tibet Plateau and South China, forming multiple heavy precipitation processes. The center of the water vapor load is mainly located in the southern part of the Yangtze River to the central and northern part of South China, resulting in abnormally high precipitation in this area.
According to the climate law of the mainland, South China enters the pre-flood season in April every year, and heavy rain and strong convective weather often occur, but this year is different. According to experts, this year's pre-flood season in South China is quite different from the past.
Zheng Zhihai said that in previous years, the South China Sea monsoon usually did not break out in April, and the water vapor conditions in South China were generally not very abundant, so although heavy precipitation occurred frequently, it was usually not large in scope and did not last long. In April this year, although the South China Sea monsoon has not yet erupted, the water vapor conditions are already very good, and the subtropical high continues to be strong, so the water vapor conditions continue to be favorable. Therefore, this year's precipitation process is more intense, lasts for a long time, and has a large impact range.
Will the rainfall in the south continue to increase this year after entering the flood season?
According to experts, during this year's flood season, the overall deviation of the mainland's climate conditions is expected to be more extreme, waterlogging is heavier than drought, precipitation in the eastern monsoon region is generally more, and regional and phased flood disasters will occur more. The precipitation in the middle and lower reaches of the Yangtze River, Huaihe River basin and Taihu Lake basin in the southern region is expected to be significantly higher than that in the same period of the year, while the precipitation in the middle and lower reaches of the Songhua River basin and the Yellow River basin in the north is also on the high side.
Source: People's Daily, China Weather Network