Science and Technology Daily, Beijing, March 1 (Reporter Fu Lili) "From the judgment criteria, the winter of 2023/2024 is neither a warm winter nor a cold winter, and is a normal year." At a press conference held by the China Meteorological Administration on the 1st , said Jia Xiaolong, deputy director of the National Climate Center.
The El Niño event formed and developed last year and continues to this day.
Generally speaking, the probability of a warm winter in my country is higher in El Niño years. Why was the winter just past not a warm winter?
Jia Xiaolong said that from a statistical point of view, the probability of warm winters in my country during El Niño years is relatively high, but the most important factors affecting the cold and warm winters in my country are mid- and high-latitude circulation systems such as the Siberian High and the polar vortex, and the influence of these mid- and high-latitude circulation systems The changes mainly depend on the internal dynamic processes of the atmosphere and are relatively less directly affected by El Niño events.
Jia Xiaolong said that the determination of warm winter is based on the average temperature throughout the winter and compares it with normal temperatures.
For example, there are more than 2,500 meteorological stations across the country. If the average winter temperature at a single station exceeds the station's warm winter threshold, it can be defined as a warm winter at a single station; if more than half of the stations across the country experience a warm winter, it is defined as a national warm winter.
In the winter of 2023/2024, the national average temperature is -2.8°C, which is 0.3°C higher than the same period in normal years.
The national warm winter index is 36.7%, that is, 36.7% of stations across the country have experienced warm winters, and the cold winter index is 15%, neither of which has reached half.
Therefore, overall, the winter of 2023/2024 is a normal year.
Jia Xiaolong said that even if there is a mild winter in my country in a certain year, there will be obvious regional differences, and it cannot be ruled out that the temperature in some areas is significantly lower.
At the same time, there may also be extremely strong cold waves in mild winter years, leading to periodic strong cooling.
The spatial differences in temperature in the winter of 2023/2024 are also 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.
From a weather perspective, Jia Xiaolong said that cold air activities were more active this winter, with more cold waves and stronger intensity. A total of 11 cold air processes affected my country (including 3 cold waves), which was more than the same period in normal years.
This is because the mid- and high-latitude circulation systems in this winter show strong intra-seasonal variation characteristics. Winter monsoon circulation systems such as the Siberian High are periodically stronger, resulting in relatively large fluctuations in temperature.