Observation And Study Of Raindrop Spectrum In Hilly And Plain Areas In Central Inner Mongoli

In view of the current situation that the ecological environment of the Yellow River basin is seriously damaged,this paper selects the central Inner Mongolia region of the Yellow River basin as the key research area.Based on the ground-based raindrop spectrometer data in the past four years,we analyze the characteristics and evolution of raindrop size distribution among different terrain,different clouds and different seasons of precipitation in the central Inner Mongolia region.On this basis,the maximum particle size method is introduced to improve the calculation results of rain intensity.Through the research of this paper,it provides a basis for the scientific and reasonable development and utilization of cloud water resources and weather modification operations in the local area.The following conclusions are specifically obtained:(1)The raindrop size distribution of different terrain,different clouds and different seasons of precipitation in central Inner Mongolia are very different.The Gamma distribution obtained by the M246 order moments can better reflect the characteristics of raindrop size distribution in the region.The raindrop size distribution in Baotou is the widest,with the largest droplet size up to 6.65 mm,the most small droplets,and the droplet mass weight diameter up to 4.2 mm.The raindrop size distribution in Hohhot is the narrowest,with the largest droplet size up to 5.25 mm,few small droplets,and the droplet mass weight diameter up to 3.1 mm.The parameters of raindrop size distribution in Junger are basically between Baotou and Hohhot.(2)The central region of Inner Mongolia is mainly composed of stratocumulus precipitation,followed by stratus precipitation.The raindrop size distribution of stratus precipitation is the narrowest,and the maximum particle size of raindrops is 2.977 mm.The mass weight diameter of raindrops is basically less than 1.8 mm,and the slope of raindrop size distribution is large.The radar reflectivity factor is the smallest,and the rain intensity is the smallest.The rain droplet spectrum of cumulus clouds is the widest,and the maximum droplet diameter is 6.65 mm.The number of large droplets is more,and the droplet mass weight diameter is less than 3.2 mm.The slope is small,and the radar reflectivity factor is the largest,and the rain intensity is the largest.The raindrop size distribution of stratocumulus precipitation is intermediate between stratus and cumulus,and the number of large raindrops is less,and the raindrop mass weight diameter is less than 2.9mm.(3)The main precipitation clouds are different in different seasons,and there are seasonal changes in different types of precipitation clouds,which is the main reason for the seasonal differences in the raindrop size distribution.The raindrop size distribution of stratus,stratocumulus and cumulus precipitation in central Inner Mongolia is wider in summer,and the number concentration of raindrops at each scale is higher.Parameters such as maximum raindrop size,mass weight diameter,and dispersion vary more in summer time,reflecting the characteristics of precipitation instability in summer.The radar quantitative precipitation estimation method underestimates or overestimates the precipitation of different regions,different clouds and different seasons.It is necessary to adjust the quantitative precipitation estimation appropriately.(4)The introduction of maximum particle size in the calculation of rainfall intensity can improve the calculation results of rainfall intensity in central Inner Mongolia.Using the Gunn-Kinzer terminal velocity formula modified by the actual air density can improve the terminal velocity calculation results of raindrops above 1.5 mm and further enhance the fitting effect of raindrop size distribution.