China News Service, Beijing, March 1 (Reporter Chen Su) Was the winter that just passed a cold winter or a warm winter?
What is the impact of El Niño?
On the 1st, the China Meteorological Administration responded and interpreted this.
At the China Meteorological Administration press conference held that day, Jia Xiaolong, deputy director of the National Climate Center, said that the determination of warm winter is based on the average temperature throughout the winter and is compared with normal temperatures.
For example, there are more than 2,500 stations in the country. If the average winter temperature at a single station exceeds the warm winter threshold of the station (obtained through tertile probability statistics), it can be defined as a warm winter at a single station. If more than half of the stations in the country have If a station experiences a warm winter, it is defined as a nationwide warm winter.
"Therefore, even if China has a mild winter in a certain year, there will be obvious regional differences, and it does not rule out that the winter temperature in some areas is significantly lower. In warm winter years, it does not rule out periodic strong cooling caused by extreme cold waves." Jia Xiaolong said .
According to statistics, in the winter of 2023/2024, the national average temperature is -2.8°C, 0.3°C higher than the same period in normal years, and the 10th warmest period in history since 1961.
Jia Xiaolong said that in the winter of 2023/2024, China’s warm winter index was 36.7%, that is, only 36.7% of sites across the country experienced warm winters, and the national cold winter index was 15.0%, neither of which reached half. Therefore, overall, in the winter of 2023/2024, It is a normal year, but the spatial difference is relatively large. Judging from the spatial distribution of the warm winter index: warm winters mainly occur in southern China, southwest and other places, while cold winters mostly occur in southern North China, Huanghuai, and Jianghuai areas.
Jia Xiaolong said that cold air activities will be more active in the winter of 2023/2024, with more cold waves and stronger intensity. A total of 11 cold air processes will affect China (including 3 cold waves), which is more than the same period in normal years.
Circulation systems at mid- and high-latitudes in winter show strong intraseasonal variation characteristics. Winter monsoon circulation systems such as the Siberian High are periodically stronger, and temperatures fluctuate greatly.
"Statistically speaking, the probability of a 'warm winter' in China during El Niño years is relatively high. However, the most important factors affecting the cold and warm winters in China are mid- and high-latitude circulation systems such as the Siberian High and the polar vortex. Changes in these mid- and high-latitude circulation systems It is mainly determined by the internal dynamic process of the atmosphere and is relatively less directly affected by the El Niño event," Jia Xiaolong said.
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