□ A cold wave cooling process is a weather event with a short time scale, and only by counting whether the average temperature of the whole winter is significantly higher or lower than that of the same period in history can it be determined whether it is a warm winter or a cold winter.
□ In the latter winter (January to February 2024), except for the northeast of Inner Mongolia, northern Heilongjiang, most of Tibet, and southern Qinghai, where the temperature is lower than that of the same period in normal years, the temperature in most parts of China is close to normal, but the cold and warm fluctuations are obvious, or the temperature "roller coaster" will be experienced again.
In December this year, the country experienced a "roller coaster" of temperature fluctuations that continued to warm in the early stage and cooled sharply in the later period. Under the influence of two consecutive rounds of large-scale rain and snow, on December 12, the China Meteorological Administration issued a freezing warning again after 12 years; On December 12, the first yellow warning for low temperature this winter was issued. Subsequently, the temperature in most parts of China repeatedly hit new lows. Didn't you say that this year was the warmest year, and why was it so cold?
Meteorological monitoring data show that from December 12 to 1, the national average temperature is higher than that of the same period in normal years, but from the 13th, a wide range of cold wave weather processes began to affect China from west to east, with 14 national meteorological stations reaching or exceeding 95 °C in the process, and 20 national meteorological stations breaking through the historical extreme. The area with the maximum cooling range of more than 10°C in the process is about 8.596 million square kilometers, accounting for about 7.62% of the country's land area.
Xu Jun, chief forecaster of the Central Meteorological Observatory, said that although the strong cold wave process has ended, most of China is still controlled by a strong cold and high pressure, and the cold tone will continue, and the temperature will continue to be low.
This autumn was judged to be the "warmest autumn" since 1961, and the temperature in northern China was abnormally high, and many places were collectively "late" in winter. In late October, the National Climate Center of the China Meteorological Administration conducted a comprehensive analysis and judged that it is expected that this winter (December 10 to February 2023), the temperature in most parts of the country will be close to the same period of the year or high; At the beginning of November, the maximum temperature at 12 meteorological observation stations across the country exceeded the local historical extreme value in November.
At the time, many people felt that this winter must be a warm winter. Zhou Bing, chief expert of climate services at the National Climate Center, said that when it comes to a certain year, a certain season or a certain month, it is not determined by a single weather event, but by comparing whether the average temperature of the entire period of time is significantly higher or lower than that of the same period in history. "A cold wave cooling process is a weather event with a shorter time scale, while a warm winter or cold winter is a seasonal weather event with a longer time scale. It is only by counting whether the average temperature for the whole winter is significantly higher or lower than that of the historical period, and whether it is a warm or cold winter. Zhou Bing said.
According to the latest monitoring by the National Climate Center, since the equatorial eastern Pacific Ocean entered an El Niño state in May 2023, the SST index in key areas has shown a continuous trend of rapid warming from May to October, and has exceeded 5.5°C for five consecutive months.
El Niño will increase the probability of a warm winter, why is it so cold? Zhou Bing said that El Niño is indeed one of the reasons for China's warm winter. For our country, the occurrence of El Niño often leads to more precipitation in the south and warmer in the north. However, the periodic cold air activities are still relatively frequent, which means that the fluctuations of cold and warm are more obvious.
Data show that from 1951 to 2000, there were 14 El Niño events, and 13 of them had warm winters in China. The most recent El Niño event occurred from November 2019 to March 11, when the average temperature in China was -2020.3°C, 2.3°C higher than the average for the same period of the year, and the fifth highest for the same period since 1.
El Niño is not the same as a warm winter, and the cold wave has not "slapped El Niño in the face". Scientific studies have shown that increased greenhouse gases, weakening East Asian winter monsoons, volcanic and solar activity, among others, are all factors that may contribute to the warm winters. "China's climate types are complex and diverse, and there are many influencing factors, even in a warm winter, there will be phases of cold, cold waves and heavy snowfall scenes will appear." Zhou Bing said.
Will it be cold next? The National Climate Center predicts that in the latter winter (January to February 2024), the intensity of the East Asian winter monsoon will be generally weak, except for the northeast of Inner Mongolia, the north of Heilongjiang, most of Tibet, and the south of Qinghai The temperature is lower than that of the same period in normal years, but the temperature in most parts of China is close to normal, but the cold and warm fluctuations are obvious, or the temperature "roller coaster" will be experienced again.
Meteorologists warn that temperature forecasts often only give a trend of warmer or colder temperatures. For the public, whether it is a warm winter or a cold winter, it is necessary to pay attention to the weather forecast and early warning information in time, add clothes and keep warm in a timely manner, and take protective measures. (Economic Daily reporter Guo Jingyuan)