Severe meteorological drought in some areas of Guangdong Province may last until early spring of next year

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 Severe meteorological drought in some areas of Guangdong Province may last until early spring of next year


In response, climate experts said that since September, no typhoon, strong subtropical high (hereinafter referred to as subtropical high), weak cold air intensity and high temperature are the main reasons for the current drought in Guangdong, which may last until the early spring of next year.

Current situation: most cities and counties have moderate or above meteorological drought, and some areas have reached the standard of severe meteorological drought

Due to the lack of temperature, high rainfall, the meteorological drought in Guangdong has continued to develop since the middle of September. The latest drought monitoring on November 11 shows that most of Guangdong Province has experienced moderate or above meteorological drought, and some areas in the east of Guangdong, such as Chaozhou and Shantou, have experienced severe meteorological drought.

According to the statistics of Guangdong Climate Center, from September to November 10 (the same below), the average temperature of the whole province is 25.4 u2103, 0.7 u2103 higher than that of the same period of the whole year, among which the average temperature of Dongguan, Shunde, Panyu and other five cities and counties is the highest in the same period of history. The average rainfall of the whole province is 144.8mm, 41% less than that of the same period of the whole year, of which more than 80% is less in Raoping, Shantou, Nanao, Lufeng and other cities and counties, and Raoping has the lowest rainfall in the same period of history, especially since October, 10 cities and counties, such as Raoping, Huilai and Nanao, have had less than 5.0mm rainfall, and three cities and counties, including Chaoyang, Shantou and Chenghai, have had the least rainfall in the same period of history.

As the capital city of Guangdong Province, since September 18, 2019 (to November 10), the average rainfall in Guangzhou is only 39.9mm, 70% less than the same period of the year, which is the sixth smallest in the same period of history. According to the monitoring results of daily drought index in Guangzhou, mild weather droughts began to appear in Conghua, Huadu and Zengcheng in late October, and then the degree became worse. At present, moderate weather droughts have appeared in the central and northern regions. Although the autumn drought is obvious this year, due to more rain in the early stage and sufficient water storage in the reservoir, it has not caused serious impact, which is not abnormal compared with history.

According to the statistics of Guangzhou Climate Center, since the new century, the more serious autumn drought years in Guangzhou are 2004, 2005, 2007, 2009 and 2010, and some of them have the continuous drought in autumn, winter and spring. For example, the continuous drought in autumn, winter and spring started on September 23, 2004, the average precipitation in all regions is less than 60% than that in the same period of the whole year, resulting in the more serious drought in Guangzhou, and the growth and production of late rice and other crops As a result, crops in Guangzhou suffered 210000 mu of drought, including 46000 mu of serious drought. Due to the lack of water in the reservoir, the low water level in the river, and the phenomenon of seawater backflow in the coastal areas.

Cause of formation: subtropical high, cold air and typhoon have their share

The weather defines the drought from August to October as autumn drought. Historical analysis shows that the probability of autumn drought is higher in Guangdong, among which the drought lasting more than 50 days occurs once every two years in the north and three times every ten years in the South and central.

However, it is worth mentioning that although the probability of autumn drought in Guangdong is high, the causes of each drought are different.

For this autumn drought, Wu Hongyu, chief expert of Guangdong Climate Center, and Wang Ting, senior engineer of Guangzhou Climate Center, all said that since September, the main reasons for the current drought in Guangdong are the lack of typhoons, strong subtropical high, weak cold air intensity and high temperature.

Wu Hongyu said that since September, due to no typhoon landing or serious impact on Guangdong, and because the intensity of subtropical high is stronger than that of the same period throughout the year, and the location is westward, the number of cold air affecting Guangdong southward is less, and the intensity is obviously weaker, resulting in less temperature, high rain and continuous development of meteorological drought since the middle of September.

Wang Ting said that this autumn, the Northwest Pacific subtropical high is strong and its downdraft will cause the temperature to rise. Taking Guangzhou as an example, the average temperature of Guangzhou since September 18 is 24.9 u2103, 0.6 u2103 higher than that of the same period all year round. The long-term hot and sunny weather leads to a large amount of evaporation and consumption of water vapor, and serious water deficit in the soil, which makes the meteorological drought continue to develop.

Another meteorological expert said that this year is the end year of El Nino. The El Nino event started in September last year ended in July this year. According to the data for many years, in the autumn of the end year of El Nino, the central and high latitudes of Eurasia are dominated by zonal circulation, and the East Asian trough is weak, which means that it is not conducive to the South transportation of cold air in the north.

Later stage: the drought may last until the beginning of next spring, and the crops need to take active measures to resist drought and ensure harvest.

According to the forecast of the provincial meteorological station, from the night of the 13th to the 14th, affected by the new cold air from the north, the average temperature in Guangdong dropped 3-5 u2103; the cloud amount increased on the 13th, with showers in some cities and counties; from the 14th to the 15th, most of them were sunny to cloudy.

Wu Hongyu said in an interview with reporters that it is expected that Guangdong will still maintain the situation of high temperature, high rain and little weather in the middle and late November, and the weather drought will continue to develop. This winter and next spring, it is expected that the temperature in most parts of Guangdong is on the high side and the precipitation is on the low side. Except for the southwest, the meteorological drought in most parts of Guangdong will continue to develop.

Wang Ting also said that in the next 11-12 months, the average annual precipitation in Guangzhou is only 69.5mm, which is a rainy season in the climate. It is predicted that the drought is likely to last until early spring, i.e. continuous drought in autumn, winter and spring is more likely. Wang Ting reminded that the continuous development of the drought will gradually affect industrial and agricultural production and peoples lives, and asked relevant departments to take measures in advance. It is worth noting that in recent months, due to the sunny and dry weather in Guangdong Province, a total of 108 forest fire warnings were issued in Guangdong Province on December 12. Among them, 100 are red, 7 are orange and 1 is yellow. Guangdong forestry bureau said that Guangdong has entered the special forest protection period, and more than 30000 forest protection workers have been on duty. Source: Yangcheng school editor in charge: Dai Wenjia, nb12498

Wang Ting also said that in the next 11-12 months, the average annual precipitation in Guangzhou is only 69.5mm, which is a rainy season in the climate. It is predicted that the drought is likely to last until early spring, i.e. continuous drought in autumn, winter and spring is more likely.

Wang Ting reminded that the continuous development of the drought will gradually affect industrial and agricultural production and peoples lives, and asked relevant departments to take measures in advance.

It is worth noting that in recent months, due to the sunny and dry weather in Guangdong Province, a total of 108 forest fire warnings were issued in Guangdong Province on December 12. Among them, 100 are red, 7 are orange and 1 is yellow. Guangdong forestry bureau said that Guangdong has entered the special forest protection period, and more than 30000 forest protection workers have been on duty.