Since the beginning of December, the temperature in our country has been like a roller coaster, experiencing fluctuations from continuous warming to sharp cooling. At the same time, precipitation is higher than in the same period of the year. However, this contradicts the warmest year in the world before, why is the cold wave so cold?
In fact, global warming has led to warming in the Arctic, which in turn weakens the westerly jet stream and polar vortex, making it easier for cold air to move south, leading to frequent cold events such as cold waves. Although the national average temperature this autumn is the highest on record, the cold wave weather is not judged by a single weather event, but by comparing the average temperature over the entire period. Therefore, although we have experienced continuous warmth in the early stage, the overall cold wave weather is still very cold.
According to data from the National Climate Center, the first half of December this year was significantly warmer, but then it cooled significantly. In addition, most of the northern region also has significantly more precipitation. For the entire time period, the national average temperature is -13, 0. higher than the same period of the year9℃。Temperatures are predominantly high in most areas.
Under the influence of cold wave weather, there has been a large-scale cooling phenomenon across the country. According to statistics, at least 95 countries have a cooling range of 20 or more, of which the area with a cooling range of more than 14 is about 16250,000 square kilometers, accounting for 62 of the country's land area2%。Under the influence of this cold wave, the cumulative precipitation in southeastern North China, most of East China, northern and central China generally exceeded 10 mm, and even exceeded 25 mm or even 50 mm in some areas.
According to the National Climate Center, the intensity of the East Asian winter monsoon is generally weak in the latter winter (January-February 2024). Although the temperature in northeast Inner Mongolia, northern Heilongjiang, most of the country, and southern Qinghai may be low, the temperature in most areas is close to the normal level, but the fluctuations in cold and warm are more obvious, and it may experience a "roller coaster" of temperature again.
In terms of precipitation, the precipitation in the central and eastern parts of China is more in the latter winter, while the precipitation in the rest of the country is close to normal or less. In addition, the cold air activity will be more active, and there may be a phased strong cooling and heavy snowfall process in the northern region again, while there may be a phased low temperature rain, snow and freezing weather in the southern part of the Yangtze River and the eastern part of the southwest region. During the intermittent period of cold air, atmospheric diffusion conditions deteriorate, and fog and haze may occur in the Beijing-Tianjin-Hebei region and its surroundings, the Fenwei Plain and the Yangtze River Delta.
In the context of global warming, the warming of the Arctic region has led to the melting of ice sheets and the warming of the oceans, which in turn has affected atmospheric circulation. In this case, the westerly jet stream and polar vortex are weakened, and cold air is more likely to move south, leading to frequent cold events such as cold waves.
Although global warming has led to an increase in the overall temperature of the planet, it does not mean that cold weather will disappear. The cold wave is still in the context of global warming and is likely to become more intense. This is because the Arctic region is unusually warming due to global warming, making cold air more active and more likely to move south. At the same time, global warming may also lead to climate anomalies, affecting the generation and propagation paths of cold air, making the emergence and development of cold waves more complex and changeable.
Therefore, the strong cold wave in the context of global warming does not mean the negation of global warming, but in the context of global change, the climate phenomenon is more complex and changeable. It also reminds us that global climate monitoring and research need to be further strengthened to better understand and respond to the impact of global warming on the climate.