Abstract：using the observed data and ERA5 reanalysis data,the characteristics of two types of rainstorms affecting the river source are compared and analyzed.The results show that the two types of rainstorms are formed by the cold air flowing southward under the guidance of the continental high pressure and the sea high pressure,respectively;Under the favorable conditions of water vapor convergence,strong dynamic uplift and unstable stratification of “upper dry and lower wet”,the frontogenesis of type I rainstorm rises to 700 hPa,and the heavy rainfall develops in the frontogenesis area near the cold shear line.Under the conditions of abundant water vapor,weak dynamic uplift and thermally unstable stratification,the heavy rainfall developed in the wind direction convergence area of the frontal zone on the south side of the warm shear line,and the frontogenesis was below 850 hPa,and the frontogenesis center was highly overlapped with the significant wet zone.The differences in the convergence area of water vapor flux divergence,horizontal frontogenesis range and vertical frontogenesis height have indicative significance for the prediction of the influence range of the two types of rainstorms.
2026, Vol. 43 
