The Effect Of Relative Growth Of Ice Particles And Humidity In The Lower Layer On The Microphysical And Electrical Procedure In Thunder Cloud

In order to realize the effect of relative growth of ice phase particles in different conditions and humidity in the lower layer on the microphysical and electrical procedure within the thunder cloud, the non-introduction electric parameterization scheme based on Saunders, et al. (1991) laboratory results is introduced into the three-dimensional dynamic-electrification coupled model. Through simulation process of a typical thunderstorm, the microphysical processes of graupel and ice crystals. The changes in growth situation of graupel particles and ice crystals in the different time of thunder cloud mature period are analyzed, and we compare the non-inductive electric charge transfer polarity and magnitude between graupel particles and ice crystals at different time with the relative growth status of graupel particles and ice crystals. We analyze the relative growth conditions of ice phase particles on the non inductive charging effect under the condition of different water vapor and temperature; in the sensitivity test, we set the different dew point temperature in the initial field for the lower layer with different moisture conditions, then we simulate and analyze influence of different low level water vapor on the occurrence and development of thunderstorm cloud. The main results are listed below:(1) Relative growth of graupel and ice crystals in the cloud is close to the source and consumption items. Different conditions of temperature and liquid water content lead to the growth and consumption of graupel and ice crystals through different microphysical processes. Production and consumption of ice phase particles affect the particle growth condition.(2) The growths of graupel and ice crystals are affected by the change of temperature, liquid water content conditions. Besides, the results show that slight differences of temperature or liquid water content conditions significantly affect the relative growth of the two types of particles.(3) The collisions and separations between graupel and ice crystal particles in the coexistence region lead to transferring charge. The relative growths of two ice particles determine charge polarity in the non-induction electrification.(4) Sensitivity experiments set different temperature humidity stratification in the lower layer. If the humidity is wetter in the lower layer temperature humidity stratification, the atmosphere will be not stable which leads to the occurrence of strong convection. In the strong convection, thunder cloud and the most rising velocity develop more quickly, and last longer.(5) Wetter humidity in the lower layer provides more sufficient water vapor which provides liquid water content to the growth of particles in the thunder cloud, which keep the microphysical procedure longer and more active. It benefits the extension of mature stage and enhancement of electrification activity in thunder cloud. Stronger rising velocity and plenty of water vapor can generate more ice phase crystals which directly affect electrification and discharge, and form a larger charge density. Humidity in the lower layer affects significantly discharge, but the impact on the rainfall intensity is not obvious.