Source: China Youth Daily client
Qiu Chenhui, reporter of China Youth Daily and China Youth Network
In the past two days, the topic of high temperature heat waves has frequently attracted attention, and "40 °C cannot enter the national high temperature rankings" has rushed to the hot search. The number 40°C, which originally made many areas "unattainable", has appeared many times during long periods of continuous high temperatures. Many netizens said: "We are witnessing history. ”
On August 12, the Central Meteorological Observatory issued the first red warning of high temperatures this year, which is the highest level of warning of high temperatures. The maximum temperature in some parts of Shaanxi, Sichuan, Chongqing, Hubei, Hunan, Jiangxi, Anhui, Jiangsu, Shanghai, Zhejiang and other places can reach 40 to 42 °C, and the stations above 40 °C in the southern region are connected into pieces.
Previously, the Central Meteorological Observatory has issued a high temperature warning for 24 consecutive days. Chen Lijuan, chief forecaster of the National Climate Center of the China Meteorological Administration, told the China Youth Daily and China Youth Network reporter that this marks the regional high temperature weather process that has continued to affect many parts of the southern part of the mainland since June, and has reached the strongest stage so far.
So, how strong is the super hot weather? Is the continuous heat normal, and who is the "driving force behind the scenes"? Will the future become the norm? The reporter interviewed relevant experts of the China Meteorological Administration in this regard.
A question: 40 °C is standard, how strong is the strongest high temperature weather since 1961?
"At present, the regional high temperature process has not exceeded that of 2013." Chen Lijuan said that in the next two weeks, the high temperature weather in the south will continue, and in terms of duration, this year's regional high temperature process will exceed 62 days in 2013, becoming the longest high temperature process since 1961.
So, how strong was the strongest heat since 1961?
Chen Tao, chief forecaster of the Central Meteorological Observatory, said that since the end of July, the number of high temperature days on the mainland, the wide coverage, and the maximum temperature in many places have broken the historical extreme, and the high temperature heat wave weather above 40 °C has frequently appeared in many places, and the number of high temperature days and the maximum temperature in many provinces have broken through the historical record.
For example, Shanghai has a total of 40 days of high temperature above 35 °C this year. Wang Zhi, chief forecaster of the Shanghai Central Meteorological Observatory, said that as of August 13, Shanghai had a total of 6 days of high temperatures above 40 °C this year, and the extreme maximum temperature was 40.9 °C. In the next 10 days, Shanghai will continue to have high temperature weather, with extreme maximum temperatures reaching 40 °C to 41 °C.
"Since July, the extreme temperature in zhejiang has been 39 °C to 43 °C, the highest is Sanmen 43.1 °C, Yongjia 42.9 °C, Qingtian, Yunhe is 42.4 °C. Places such as Sanmen and Yongjia have broken record highs in history. Lou Xiaofen, chief forecaster of the Zhejiang Meteorological Observatory, said that it is expected that in the next 7 days, there will be local 43 ° C extreme heat in northern Zhejiang and parts of western Zhejiang, or break the extreme high temperature record.
Chongqing has experienced two rounds of high temperature weather this year, and the average number of high temperature days in the city has reached 29.3 days, the second most since 1951. Luo Juan, chief forecaster of Chongqing Meteorological Observatory, said that it is expected that from August 13 to 22, the maximum temperature in most parts of Chongqing will be 38 °C ~ 42 °C, and the local area will reach 43 °C ~ 44 °C, and the maximum temperature in some districts and counties will approach or exceed the historical extreme.
Chen Tao said that on August 12, high temperatures above 35 °C occurred in southern North China to Jiangnan and the Sichuan Basin, central and southern Shaanxi, and western Inner Mongolia, of which temperatures in most areas were 38 to 40 °C, and the local areas in eastern Sichuan, southwest and north Chongqing, southeastern Shaanxi, western Hubei, southeastern Anhui, southern Jiangsu, and north-central Zhejiang reached 41 to 43°C. Among them, The Local Area of Zhushan, Hubei Province, reached 44.3 °C, refreshing the record of the highest temperature in Hubei since meteorological records were recorded.
This is not over, and the red warning of high temperatures will continue. The Central Meteorological Observatory expects that in the next 10 days, there will still be persistent high temperature weather in Jianghuai, Jianghan, Jiangnan, Sichuan Basin and other places, and the cumulative number of high temperature days can reach 7-10 days.
Second question: What is the impact of the continuous high temperature weather, and who is the "driving force behind the scenes"?
The continuous high temperature weather is not conducive to the growth and development of crops and economic forest fruits in the south, and some areas have experienced meteorological drought.
"In view of the high temperature weather, it is necessary to take measures as soon as possible to carry out water replenishment operations and sprinkler irrigation to cool down, and remove the fruits that have been affected by heat damage as soon as possible." Chen Tao said.
According to the agricultural meteorological report recently released by the Central Meteorological Observatory, the number of days of high temperature and heat damage in Sichuan in the first season of rice is the third most in the same period in the past 10 years. Sunny heat and little rain have led to mild to moderate heat damage in most parts of jiangnan tea area, local tea plants have sunburn, and some areas of citrus, bananas, passion fruit, etc. appear cracked fruit, fallen fruit, sunburn damage and other phenomena.
In addition, the continuous high temperature and low rainfall have led to agricultural droughts in the southeast of the Sichuan Basin and south-central Anhui, which is not conducive to the production of autumn grain crops such as rice and corn in one season. Up to now, crops such as rice in the eastern part of the Sichuan Basin have been affected by high temperature heat damage more severely than in 2013.
Chen Lijuan said that according to the analysis, the possibility of less precipitation in the Yangtze River Basin in the late autumn is still relatively large, especially in the middle and lower reaches of the yangtze River Basin, there may be continuous drought in summer and autumn.
So, who is the "driving force behind the continuous high temperature weather"?
Chen Tao said that since late July this year, there have been high-temperature weather with a wide range and high intensity in the middle and lower reaches of the Yangtze River, and the causes of this are related to the abnormal conditions of atmospheric circulation.
He explained that from the current monitoring, this year's subtropical high pressure in the western Pacific Ocean is large and strong. Under its control, the southern part of the continent as a whole is controlled by sinking air currents, resulting in clear skies and few clouds. Coupled with the influence of daytime sunlight radiation, the near ground heating is strong, and the hot air is stuck on the ground, "can not be blown away, can not be dispersed", so there is a wide range of sustained high temperature weather.
Chen Tao said that in the future, the cold air in the middle and high latitudes will be weak, and there is no obvious tropical system affecting the mainland in the southern tropical ocean, so the subtropical high pressure will continue to control the Sichuan Basin to the middle and lower reaches of the Yangtze River, and the high temperature weather will continue to develop.
The heat has been going on for nearly two months, so why didn't the Central Meteorological Observatory issue the first red warning of the year until August 12? In this regard, Chen Tao said that the start of the red warning has scientific standards and strict business specifications.
"The starting standard for the high temperature red warning is that in the past 48 hours, some areas in four or more provinces have continuously experienced weather with a maximum temperature of 40 °C and above, and it is expected that the above areas will continue in the future." Chen Tao said.
On August 12, the Central Meteorological Observatory was concerned that parts of Sichuan, Chongqing, Zhejiang, Jiangsu and Hubei had already experienced sustained high temperature weather above 40 °C, at the same time, through the analysis of atmospheric circulation, there would still be a large range of high temperature weather from the Sichuan Basin to the middle and lower reaches of the Yangtze River, so it upgraded and issued a high temperature red warning on the afternoon of August 12.
Three questions: Is the continuous high temperature heat wave normal, and will it become the norm in the future?
"High temperature heat wave events in the summer are normal from a climatic point of view, but the duration, intensity, and scope of this summer's high temperature heat wave events have indeed reached a very strong level." Chen Lijuan said.
According to her analysis, the rare high temperature weather on the mainland since June this year may be the strongest high temperature event since the complete meteorological record was recorded in 1961. The occurrence of such a situation is far from a problem of weather scale, and there are deep climatic scale reasons behind this.
In fact, not only the mainland, since the beginning of summer, the western Pacific subtropical high pressure, the Atlantic subtropical high pressure and the Iranian high pressure have all strengthened, forming a large overall global warm high pressure belt, resulting in high temperature weather in many parts of the northern hemisphere.
In the sixth assessment report of the Intergovernmental Panel on Climate Change, it is pointed out that in the context of global warming, many changes in extreme weather and climate events have been observed since the middle of the 20th century, of which the frequent occurrence of high temperature heat waves is a very significant feature.
"In the context of global warming, similar to this year's high temperatures and heat, in the future summer, the frequency of occurrence may be more." Chen Lijuan said, "This year's high temperature appeared early, and the expected end time is also late, and this 'start early, end late' feature will become more and more obvious in the future." ”
The average global temperature in July 2022 is flat (in °C). Image source: Central Meteorological Observatory
Chen Tao reminded that in cities, the surge in electricity demand is one of the most significant effects caused by the continuous high temperature. The frequency of use of electrical appliances such as air conditioners under high temperature has increased significantly, which has a greater impact on energy supply, and relevant departments should make emergency plans according to temperature forecasts to ensure power supply.
For the public, he suggested that during the high temperature weather, it is necessary to minimize long-term outdoor activities, replenish water in time, and avoid the effects of heat stroke and other potential diseases that are easily induced by high temperatures.
"It is particularly important to note that it is the summer, in the hot weather, when students who are on vacation at home swim in the water to escape the heat, they must pay attention to staying away from dangerous waters to prevent drowning accidents." Chen Tao said.