On July 10, the highest temperature at Xujiahui Station in Shanghai reached 40°C, which was the earliest 40°C high temperature day since the meteorological record in Shanghai; on the 12th, the temperature in Hangzhou, Zhejiang exceeded 40°C, setting the earliest record of extreme high temperature; from 12 to 13 , there are two national meteorological stations in Jiangsu, Dongshan 40 ℃, Yixing 41.3 ℃, exceeding the extreme value since the establishment of the station...
Recently, the Central Meteorological Observatory issued a high temperature warning for more than 10 consecutive days, and the highest temperature in Sichuan, Shanghai, Zhejiang, Jiangsu, Henan, Hebei and other places exceeded 40 °C.
A total of 238 national meteorological stations in Hebei, Henan, Tianjin, Yunnan, Sichuan, Zhejiang, Xinjiang and other places have exceeded the monthly maximum temperature, and a total of 71 national meteorological stations have exceeded the historical extreme value.
According to the monitoring data of the National Climate Center, since June this year (as of July 12), the national average number of high temperature days was 5.3 days, the most in the same period in history since 1961, and the comprehensive intensity was the sixth strongest since 1961.
According to the analysis of the National Climate Center, since the beginning of this century, the typical years of large-scale continuous high temperature events in the country are 2003, 2013, and 2017.
In general, this year's high temperature event started earlier than the above-mentioned three years, and the scope of influence and the highest temperature per station have exceeded those of 2003 and 2013.
Why is it so hot this summer?
According to monitoring by the National Climate Center, in June this year, the global average temperature was about 0.4°C higher than normal, the highest since 1979.
The sixth assessment report of the United Nations Intergovernmental Panel on Climate Change (IPCC) pointed out that global warming in the past 50 years is occurring at an unprecedented rate since the past 2000 years, and the instability of the climate system is increasing.
The National Climate Center pointed out that global warming is the climate background for the frequent occurrence of high temperature and heat waves in the northern hemisphere, and the abnormal atmospheric circulation is the direct cause of the frequent occurrence of high temperature and heat waves in many places around the world since June.
Yuan Yuan, the chief on duty during the flood season of the National Climate Center, introduced that since June, over the subtropical region of the northern hemisphere, the subtropical high pressure in the western Pacific (referred to as the subtropical high) belt, the Atlantic high pressure belt and the Iranian high pressure have all strengthened in stages, thus forming a large-scale global warming high pressure belt.
Under the control of the warm high-pressure zone, the prevailing downdraft is conducive to the warming of the ground. In addition, under the action of the large-scale high-pressure zone, the air is relatively dry, and it is not easy to form clouds, which also makes it easier for solar radiation to reach the ground, resulting in frequent high temperature occurrences , and the intensity is strong, resulting in sustained high temperature and heat wave events in many parts of the northern hemisphere.
Specifically for China, the ongoing La Niña event has provided important climatic background conditions for the occurrence and development of high temperature in the south since June this year.
According to statistical analysis, in the summer of the following year for most La Niña events, the subtropical high is prone to the north.
Since late June, the subtropical high has been rising northward, especially after Typhoon "Siamba" moved northward in early July, the subtropical high has strengthened to the west, and the Iranian high has been extended to the east. Combined with the mid-latitude continental high, a stable cyclone is formed over China. Warm high pressure belts, which in turn cause a wide range of high temperature weather.
In addition, due to the water vapor carried by the subtropical high, the humidity in central and eastern China is relatively high, resulting in higher body temperature.
Chen Tao, chief forecaster of the Central Meteorological Observatory, reminded that residents in relevant areas should try to avoid outdoor activities during high temperature periods, and those who work under high temperature conditions should shorten their continuous working hours; protective measures.
Hot weather will continue to develop.
According to the forecast of the Central Meteorological Observatory, as of July 26, there will be many high-temperature weather in Jiangnan, South China and other places.
From 8:00 on the 20th to 8:00 on the 21st, there were heavy or heavy rains in parts of southern Shandong, northern Jiangsu, northern and western Anhui, eastern and southern Hubei, northern Hunan, western Guizhou, and northern Yunnan.
After the 21st, the high temperature in the southern region will develop again and the scope will expand.
The National Climate Center predicts that from July 31 to August 15, the temperature in most parts of the country will be higher than the same period of the year, and there will still be periodic high-temperature heat waves in Huanghuai, Jianghuai, and the middle and lower reaches of the Yangtze River.
The public needs to pay attention to the rolling update of high temperature weather forecast warning information, and continue to do a good job in preventing heatstroke and cooling down.
Li Hongmei