Geographical location of the East Asian trough

Transverse trough refers to the east-west low pressure zone under the stable and flat westerly circulation. The transverse trough in East Asia is one of the important weather systems in East Asia, which mostly occurs in the areas of 40N to 60° n and 80E to120 E. It occurs all year round except in midsummer, but it is most frequent in winter and spring. But only when the horizontal trough line is in the south of 50N will it have an impact on the weather in China.

Under the situation of transverse trough, because the bottom of transverse trough maintains an east-west front area, it is often rainy in Jianghuai basin or Jiangnan area of China. In winter half a year, the formation of horizontal trough often leads to the accumulation of cold air, which often brews a strong cold wave outbreak. Because of its inherent characteristics, the transverse trough is generally stable, and the trough line is slowly pressed south, which is caused by the continuous transfer of cold air from north to south. When the slot line is close to 40N, the turning problem should be considered. When the horizontal trough turns to the vertical trough and moves to the southeast, there will often be a large-scale cold wave in the whole country.