What monsoon is the autumn rain in West China related to?

West China is located in the west of China, distributed in Qinghai, Xinjiang' Tibet', and the central and western Gansu. The main reason for the autumn rain in West China is that, under the guidance of the high pressure in the Bay of Bengal, the water vapor moves northward from the northern part of the Bay of Bengal and the Arabian Sea moves eastward and northward, which has nothing to do with the southwest monsoon (that is, there is a boundary), because the altitude in this area is relatively high and the southwest monsoon cannot be transported to West China. When the cold air moves eastward and southward from the entrance of Xinjiang, it just meets the water vapor in that area, causing precipitation, so the autumn rain in West China has nothing to do with the monsoon; In winter, the Bay of Bengal high pressure weakens to the south, and the airflow north of the high pressure flows to the west. Therefore, under the guidance of the Bay of Bengal high pressure in winter, a stable westerly wind system appears in the south-central part of China! ! Meteorologist