What are the two types of quasi-static fronts in China? Time, place, cause and weather characteristics of occurrence

Quasi-static front is an inseparable front type. If you insist on dividing it, it can be divided into two types: cold air mass attacking warm air mass and warm air mass attacking cold air mass. There are mainly four quasi-static stops in China: Jianghuai quasi-static stop, South China quasi-static stop, Tianshan quasi-static stop and Yunnan-Guizhou quasi-static stop. Among them, Jianghuai quasi-static front and Yunnan-Guizhou quasi-static front are the most famous two.

The quasi-static front of the Yangtze-Huaihe River appears in the middle and lower reaches of the Yangtze-Huaihe River Basin from June to July in early summer every year, and it is formed in two forms: local frontogenesis and cold front slowing down when it meets active southwest airflow southward. When a large trough moves eastward and the cold advection behind the trough is strong, the quasi-static front can be turned into a south cold front. When the Pacific subtropical high moves eastward, the intersection of north-south airflow moves from land to sea, and the cold air that originally stayed in the Jianghuai basin degenerates, and the quasi-static front of Jianghuai disappears.

Yunnan-Guizhou quasi-static front is also called Kunming quasi-static front. Located in Sichuan, Guizhou, Yunnan and Guangxi, it is distributed in the northwest-southeast direction. It mainly appears in winter and often lasts for more than ten days. It was formed by the cold front moving southwest under the influence of the slope topography of Yunnan-Guizhou Plateau. It is characterized by a small slope of the front. Clouds and precipitation are widely distributed near the front, which often leads to long-term continuous rainy weather.