Traditional Culture Encyclopedia - Weather inquiry - About this snowstorm

About this snowstorm

During the period from June 5438+ 10 this year, especially since the middle of June 5438+ 10, due to the combined influence of cold and warm air, large-scale freezing rain and snow weather occurred in the central and eastern regions of China, resulting in large-scale snowstorms in the whole country, blizzards in some areas, freezing rain and heavy rain in most parts of the south of the Yangtze River, eastern Hubei and southern Anhui. At the same time, the temperature in the central and eastern regions is low, and some areas are 2 degrees or even 4 degrees lower. In addition, compared with the same period of normal years, the number of days of continuous rainfall in some provinces in central and eastern China is 7 ~ 10 more. It should be said that such a climate phenomenon since June+10 in 5438 is abnormal compared with the same period in previous years. This abnormality is most directly manifested in three aspects. First, the precipitation is relatively large, including rain and snow. In addition, the temperature is low, especially the average temperature is significantly lower than the same period of the previous year, and some areas have reached historical extremes. In addition, the number of rainy and snowy days is obviously higher. According to our current statistics, there are 12 provinces with low temperature and continuous rainy days, which is the most since 19 and 5 1 year.

For China, there are two factors that cause large-scale heavy precipitation: 1, cold air 2, and warm and humid airflow in the southeast and southwest. Only when these two points have the same influence will the above situation occur.

It should be said that the most direct reason for the occurrence of such a wide range of low temperature anomalies in rain and snow is the anomaly of atmospheric circulation system, especially since June+10 in 5438, the circulation in the middle and high latitudes is mainly meridional, with frequent cold air activities. In addition, the subtropical system is strong, northwest than normal, which is conducive to transporting warm and humid air from the south to the north. On the one hand, the cold air in the north is very active, on the other hand, the warm and humid airflow in the south is constantly transported northward. The intersection of cold and warm air flow is mainly located in the central and eastern regions of China, which creates favorable circulation conditions for large-scale rain and snow weather. In meteorology, this circulation anomaly is generally attributed to two reasons. On the one hand, it is determined by the motion law of the atmosphere itself, on the other hand, it is influenced by external compulsion. This year's circulation anomaly is related to the La Nina event in August 2007.