China news agency, Beijing, August 13th (Reporter Chen Su) This year, China experienced extremely high temperature and heat wave. With the arrival of "dog days", the high temperature has been further upgraded recently. On the 12th, the China Meteorological Bureau issued the first high-temperature red warning this year. The high temperature in the middle and lower reaches of the Yangtze River and the southwest region continued to develop, and the drought worsened. Why is the high temperature in China so extreme this year? On the 13th, many experts were interviewed by reporters to interpret the high temperature situation this year.
According to the statistics of the meteorological department, since late July, southern China has experienced a wide range of high-temperature weather with high intensity. As of the 13th, there were 40 days of high temperature above 35 degrees in Shanghai this year, and the extreme maximum temperature reached 40.9 degrees. Since July, the average number of days with high temperature above 35℃ in Zhejiang Province is 31 days, and the average number of days with high temperature above 38℃ is 16 days, both of which are the highest in the same period in history, among which Sanmen in Zhejiang Province has reached 43.1℃. Since July, Chongqing has experienced two rounds of high-temperature weather, with the average number of high-temperature days in the city reaching 29.3 days, the second highest in the same period since 1951. It is predicted that the large-scale high-intensity high-temperature weather will continue in the future, with the local temperature reaching 43-44℃ and the highest temperature in some districts and counties approaching or exceeding the historical extreme.
On the 12th, China Meteorological Bureau issued the first high-temperature red warning in China this year. On the 13th, the high-temperature red warning continued. It is estimated that the temperature in parts of 10 provinces and cities such as Jiangsu, Zhejiang and Shanghai will reach 40-42℃, and the local temperature will exceed 42℃.
Talking about the causes of this round of high temperature weather, Chen Tao, chief forecaster of the Central Meteorological Observatory, said that the high temperature weather has a certain relationship with the abnormal situation of atmospheric circulation. From the monitoring point of view, the western Pacific subtropical high has a large range and strong intensity. Under its control, the southern region as a whole is controlled by downward flow, and the sky is clear and partly cloudy. Under the influence of sunshine radiation during the day, the near-surface heating is relatively strong, so there is a large range of high temperature weather.
Chen Tao predicted that the subtropical high will still control the middle and lower reaches of the Yangtze River in the future, and the high temperature weather from Sichuan Basin to the middle and lower reaches of the Yangtze River will continue to develop or maintain. It is expected that the high temperature red warning will last for at least 4 to 5 days.
Chen Lijuan, chief forecaster of the National Climate Center, said that according to the forecast, the duration of this regional high temperature process is expected to exceed 62 days in 2013, making it the longest high temperature process since 1961.
Affected by high temperature weather, severe drought has occurred from Sichuan Basin to the middle and lower reaches of the Yangtze River. Since July, the rainfall in the Yangtze River basin has been 40% less than normal, the high temperature days in some areas in the middle and lower reaches are close to 30 days, and the days without effective rainfall in some areas have exceeded 20 days. The water levels in the main stream of the Yangtze River, Dongting Lake and Poyang Lake are the lowest in the same period since the measured records were recorded. According to the data of the Ministry of Water Resources of China on the 11th, the drought in the Yangtze River Basin has affected 9.67 million mu of cultivated land in Anhui, Jiangxi, Hubei, Hunan, Chongqing and Sichuan, and affected the water supply of 830,000 people.
Chen Tao said that it is expected that the meteorological drought will continue or worsen in the future. The continuous high temperature has a great impact on cash crops such as tea and fruits in the south, and the high temperature has also increased the demand for electricity and energy, and the demand for electricity by residents has increased, which has increased the pressure on electricity and energy supply.
"According to the monitoring of the National Climate Center, the rare high temperature weather in China since June this year is actually the strongest event since the complete meteorological record in 1961." Chen Lijuan said that, in fact, the occurrence of high-temperature heat wave events in summer is normal from the climate point of view, but the duration, intensity and influence range of this summer’s high-temperature heat wave events have indeed reached a very strong level. This is far from the problem of weather scale, and there must be deep climate scale reasons behind it.
She said that the sixth assessment report of IPCC (United Nations Intergovernmental Panel on Climate Change) pointed out that under the background of global warming, many extreme weather and climate events have been observed since the middle of the 20th century, among which the frequent occurrence of high temperature and heat waves is a very remarkable feature. Therefore, under the background of climate change, high-temperature heat wave events will become a new normal. It is expected that similar high-temperature heat waves will occur more frequently in the future summer, and the characteristics of long-term high temperature may become more and more obvious.
