Many parts of my country have entered "barbecue" mode, and climate warming is the "culprit"

Recently, with the strong summer heat, many parts of my country have entered "barbecue" mode.

Monitoring by the National Climate Center shows that since June this year (as of July 12), my country has had an average of 5.3 days with high temperatures, 2.4 days more than the same period in previous years, the most since 1961. A total of 71 national meteorological stations in China recorded record high temperatures, including Lingshou (44.2°C), Gaocheng (44.1°C), Zhengding (44.0°C) and Yanjin (44.0°C) in Hebei Province, with daily maximum temperatures exceeding 44°C.

Fu Jiaolan, chief forecaster and senior engineer at the Central Meteorological Observatory, said that since June 13, my country has experienced the first regional high temperature weather process this year, which is wide in scope, long in duration, strong in extremeness and has a great impact. As of July 12, the high temperature event has lasted for 30 days, covering an area of ​​5.021 million square kilometers and affecting more than 900 million people.

Fu Jiaolan said that since the beginning of the 21st century, typical years of large-scale continuous high temperature events in my country include 2003, 2013, and 2017. Overall, this year's high temperature event started earlier than the above three years, and the duration and the number of historical extreme stations are not as long as those three years. Although the affected area and the highest temperature at a single station are not as long as those in 2017, they have exceeded 2003 and 2013.

In fact, it is not just my country. According to the National Climate Center, the global average temperature in June this year was about 0.4℃ higher than usual, the highest since 1979, with northern Russia and western Europe exceeding 2℃. The highest daily temperature in Spain, France and Italy exceeded 40℃, and many cities set new high temperature records.

The sixth assessment report of the Intergovernmental Panel on Climate Change (IPCC) of the United Nations pointed out that global warming in the past 50 years has been occurring at an unprecedented rate since the past 2000 years, and the instability of the climate system has intensified. UN Secretary-General Guterres called it a "red alert for all mankind." "Global warming is the climate background for the frequent high temperature heat waves in the Northern Hemisphere, and the abnormal atmospheric circulation is the direct cause of the frequent high temperature heat waves in many parts of the world since June." Fu Jiaolan said.

Experts from the National Climate Center said that since June this year, the western Pacific subtropical high pressure belt, the Atlantic high pressure belt and the Iranian high pressure belt have all strengthened in stages over the subtropical regions of the Northern Hemisphere, thus forming a large-scale global warm high pressure belt. Under the control of the warm high pressure belt, the prevailing downward airflow is conducive to ground warming. In addition, under the influence of the large-scale high pressure belt, 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 temperatures and strong intensity, which in turn caused continuous high temperature heat waves in many parts of the Northern Hemisphere.

Specifically in my country, the ongoing La Niña event has provided important climatic background conditions for the occurrence and development of high temperatures in the south since June this year, especially the strengthening of the mid-latitude warm high-pressure belt in July, leading to widespread high temperature weather.

According to statistical analysis, in the summer of the year following most La Nina events, the western Pacific subtropical high pressure (hereinafter referred to as the subtropical high pressure) tends to move northward. Since late June this year, the subtropical high pressure has moved northward, especially after Typhoon Siamba moved northward in early July, the subtropical high pressure has strengthened and extended westward, and the Iranian high pressure has extended eastward, and combined with the mid-latitude continental high pressure, a stable warm high pressure belt has formed over my country, which in turn has caused a large range of high temperature weather. In addition, the water vapor carried by the subtropical high pressure has caused high humidity in central and eastern my country, resulting in higher perceived temperatures.

Source: Science and Technology Daily reporter Fu Lili