Reasons for Less Precipitation in Zhaotong

Zhaotong City is located in the slope terrace of the transition from Sichuan Basin to Yunnan-Guizhou Plateau, and the special terrain of "one belt and three stations" facing the northeast brings difficulties to the study of hydrometeorological elements. Especially, the complicated precipitation distribution makes the north-south difference of average annual precipitation for many years reach 3.8 times. The distribution of precipitation is extremely uneven during the year, and the proportion of precipitation in flood season drops from 965,438+0% in the south to 66% in the north. The terrain is high in the southeast and low in the northeast, with the highest point of Yaoshan 4040m and the lowest point of Shuifu County 270m m.. The main mountains and rivers are arranged from south to north, and the water system is radial and inclined from southwest to northeast. Near the Sichuan-Yunnan border, the altitude rises from 500m in Sichuan Basin to1200m, forming a crescent-shaped transition zone. This special terrain plays a role in lifting the precipitation weather system in the south and coordinating the horizontal amplitude, resulting in a stable rain belt in the north. The northern end of Wulian Peak, the upper reaches of Baishui River and the headwaters of Chishui River and Wujiang River in Zhenxiong and Weixin, with an altitude of 1200~2000m, are big steps in this area.