Why is the cold wave in 216 called the "century cold wave"

Since the catastrophic cold wave disaster in 1991, there has been no comparable severe cold wave disaster in East Asia for the time being. Then, let's make some comparisons, and compare the difference between the coming severe cold wave disaster in 216 and the severe cold wave disaster in 1991 < P > First of all, the situation; Undoubtedly, the main culprit of the cold wave weather in 1991 was still the polar vortex, which occupied the north of China and accumulated a lot of extremely cold air to vent down.

The left picture shows the weather situation in East Asia on January 23rd, 216 predicted by ECMWF (European Medium Range Forecast), and the right picture shows the NCEP reanalysis situation of the cold wave weather process in 1991.

We can see that on January 23, 216, the main body of the deep purple polar vortex was located in the northeast of China, while in 1991, the main body of the polar vortex was located in the first line of Inner Mongolia to the west. Such a cold polar vortex shelf was above China's head, and the favorable weather situation pushed the polar vortex down and went deep south.

the second is the degree of influence

The left picture shows the weather situation in East Asia on January 24th, 216 predicted by ECMWF (European Medium Range Forecast), and the right picture shows the NCEP reanalysis situation chart of the cold wave weather process in 1991.

There is a thick white line in it, which represents the zero-degree line at 85HPA level. It can be seen that the possible impact of this cold wave will be no less than that in 1991. In contrast, the westerly winds in the south branch, like in 1991, came to a trough very well, but we should pay attention to the location of the subtropical high. Compared with 1991, the subtropical high in 216 is more northerly, and the warmth and humidity are more active. I believe that in the past few months, the south has felt the warmth and humidity brought by the northerly subtropical high to a greater or lesser extent, and the active warm and humid airflow collides fiercely with the deep cold air, which will probably be no less than that in 1991.

By this comparison, maybe you will know why this cold wave is called "the cold wave of the century".