Abstract:The surface raindrop spectra of stratiformis precipitation on April 4-5,2002 were measured in Mengjin and Linying stations in Henan Province.Through the comparison and analysis of the raindrop microphysical parameters and raindrop size distributions of the two stations during this precipitation process,we find that under the circumstance of stratiformis precipitation in Henan Province,the average diameter of raindrops is 10-1mm,the total number density of raindrops 100 drops/m3,and the big size raindrops which account for a small proportion of total raindrops make more contribution to precipitation intensity.The average diameter of raindrops in the warm sector ahead of a cold front is smaller than that in the cold sector behind the cold front;while the total number density of raindrops in the warm sector is greater than that in the cold sector,but the precipitation intesity in the cold sector is higher than that in the warm one.During the process of stratiformis precipitation,the raindrop spectra in the warm sector evolves from a wide spectra double-peak pattern to a narrow spectra single-peak one,while the raindrop spectra in the cold sector changes from a wide spectra single-peak pattern to a narrow spectra single-peak one.The fluctuations of the average diameter of raindrops in the warm sector are larger than those in the cold sector,which is related to the inhomogeneity of the cloud system structure and convection in the cloud.