Causes of Four Quasi-static Stop Fronts in China

Causes of Four Quasi-static Stop Fronts in China;

Quasi-static front refers to the phenomenon that the front remains in a relatively fixed position for a long time and the moving range is very small. These four quasi-static stations are mainly distributed in the middle and lower reaches of the Yangtze River for the following reasons:

Jianghuai quasi-static front: mainly occurs in the middle and lower reaches of the Yangtze River, including Jianghuai and Huanghuai areas. Its formation is mainly due to the fact that the warm and humid air in the south often extends northward to the Yangtze River basin and the area north of the Yangtze River in summer, while the cold air in the north is still quite strong, so the cold and warm air meets in the Jianghuai Basin to form a front.

Because the cold air is heavier than the warm air, and the front is southerly, under certain conditions, it may stay in this area and swing.

Kunming quasi-static stop: also known as Yunnan-Guizhou quasi-static stop. Located in the Yunnan-Guizhou Plateau, it is mainly formed by the meeting of denatured polar continental air mass and southwest monsoon. Kunming static front, also known as "Yunnan-Guizhou static front", appeared in Yunnan-Guizhou Plateau from July to August. It is low-altitude cold and high pressure, and the ground is the center of low pressure.

This front makes the cold and warm air masses in the north and south stagnate in the Yunnan-Guizhou Plateau. The south and northwest of the front are controlled by warm air masses, while the north and northeast of the front are controlled by cold air masses. However, the temperature difference between the two sides of the front on the Yunnan-Guizhou Plateau is not great.

Tianshan quasi-static front: also known as Ural quasi-static front. This front is mainly located in Russia, because the cold air from Siberia meets the warm moisture mass from the North Pacific. Because cold air is heavier than warm air and reaches the Tianshan area not far from the south, this front often swings near the Ural Mountains.

Beiping quasi-static front: also known as North China quasi-static front. This front is mainly distributed in North China, including Beijing, Tianjin, Hebei and Shandong. Its formation is mainly due to the meeting of cold air from Siberia and warm moisture mass from the Pacific Ocean. As the cold air moves southward to Taihang Mountain and Yanshan Mountain, it tends to stagnate, so this front often swings near Taihang Mountain and Yanshan Mountain.

The formation and activities of these quasi-stationary fronts are closely related to the weather system, topography and seasonal changes. During their activities, they often bring weather phenomena such as long-term and large-scale precipitation, continuous rain or snowy areas. Therefore, these quasi-stationary fronts have an important influence on the weather and climate in China.