Effect Of Middle And Low-Level Horizontal Wind Speed On Microphysics And Electrical Activity Of Thunderstorm

In order to further understanding the effect of middle and low-level horizontal wind speed on the feature of thunderstorm dynamic field,microphysics process,electrical activities and precipitation,we do sensitivity experiments in a three-dimensional dynamics-electrification coupled model with different horizontal speeds. Firstly,we do comparative analysis tests on the effect of middle level,low level horizontal wind speed on electrification and discharge,microphysics and precipitation of thunderstorm.The height from ground to1.5km is stand for "low level" and "middle level" is1.5km to5.84km.There are four cases on each level and the wind speed ratio is about0:1:2:4,respectively;Secondly, we analyse the relationship of microphysics and electrical activities in thunderstorm when middle and low-level wind speed’s changed in the whole level, the wind speed ratio is also0:1:2:4.These tests can represent the weather in general.The simulation results show that in the initial stage of development of thunder cloud,the increase of low level wind speed is not conducive to the graupel and ice crystal to grow up. In the later period,midlle level wind speed has greater impact on graupel, particle size are smaller and the number is smaller. The increase of low level wind speed has no effect on the time of reaching the max of precipitation intensity distribution,liquid precipitation distribution will broaden when low level wind enhanced,but little impact on solid precipitation distribution.When midlle level wind getting stronger, liquid precipitation intensity distribution’s biggest number will come earlier,but no change to solid precipitation,solid and liquid precipitation regional center will more prone to move if the middle level wind speed grow up.Total liquid precipitation will change in contrast when middle or low level wind speed changed. Weak low level wind is more conducive to the liquid precipitation. Total solid precipitation will first increased and then decreased when middle or low level wind getting stronger. Middle or low level wind speed in a certain range of growth is favorable for the development of lightning,but if the wind is too strong,lightning will reduce. As the middle and low level wind speed increases,particle growth was inhibited, the electrification process of thunderstorm will be slowed down and the electrification regional transfer occurs,,longer electrification time would make the storm produced more greater electric field and occurred more severe discharge process,however, if the wind is too strong,there would no lightning happen.Moderate intensity wind is most conducive to lightning.In addition,wind speed in a certain range of growth will increase the precipitation,but if the wind is too strong,precipitation will reduce.These results showed that middle and low-level wind can make significance impact on thunderstorm,we should comprehensive consider the wind influence on thunderstorm dynamic field and microphysical processes when studying the activity of storm,mechanism of lightning or precipitation or the relationship of activities of thunderstorm.