Causes of recent heavy rainfall in southern China

China has a great latitude and longitude span. Generally, a quasi-static front is formed, that is, it rains for a long time in the front area, sunny in other areas, and even drought will occur in areas controlled by cold air and high pressure. In April, with the weakening of the winter wind, the warm air mass pushed the frontal rain belt to land on the southern coast of China; In May, the summer monsoon continued to strengthen, and the warm air mass pushed the frontal rain belt to Nanling area; In June, the summer monsoon was further strengthened, and the warm air mass pushed the frontal rain belt northward to the middle and lower reaches of the Yangtze River. At this time, the cold and warm air masses are evenly matched, which leads to the frontal rain belt staying or swinging in the Jianghuai area for about a month, forming a rainy season; In July and August, the summer monsoon strengthened and moved northward, and the warm air mass pushed the frontal rain belt to reach North China and Northeast China. In September, forced by the winter monsoon, coupled with the weakening and southward withdrawal of the summer monsoon, the cold air mass pushed the frontal rain belt southward to the south of the Yangtze River. In June+10, 5438, the winter wind was further strengthened, and the cold air mass pushed the frontal rain belt to withdraw from the south of China. According to the moving direction of cold and warm air masses on both sides of the front, the front can be divided into three types: cold front, warm front and quasi-static front. The front where the cold air mass actively moves to the warm air mass is called the cold front; The front where the warm air mass actively moves to the cold air mass is called the warm front; The cold and warm air masses are evenly matched, or the front moves slowly due to the terrain, or swings in an area for a long time, resulting in rainy weather. The front with little movement is called quasi-static front. It can be seen that the nature of the front is caused by an active moving air mass. In addition, in areas where warm and humid air is controlled, the warm and humid air often rises and cools due to the sun's irradiation on the ground, forming convective clouds and producing convective rain, also known as thunderstorms. General artificial rainfall also takes advantage of this opportunity.