Numerical Simulation Of Relationship Between Lightning And Solid/Liquid Precipitation In Thunderstorms

In order to further understand the relationship between lightning and precipitation, a three dynamic-electrification model is used to simulate a multi-cell in this paper. Discussed the spatial and temporal relationship and RPF(rain yields per flash) between lightning and solid/liquid precipitation. Analyzed the micro-physics and electrical characters of particles of hydrometeors. The results show that:(1) The liquid precipitation accounts for the most part of total precipitation. With the development of convection, the proportion of solid precipitation is increasing. The time of first discharge, the beginning and peak values of liquid and solid precipitation are more in advance. The peak value of lightning is behind vertical wind and lightning number first increases then decreases. The liquid precipitation starts before solid precipitation. The first discharge lags behind the beginning of liquid precipitation, but before solid precipitation or they occur at the same time. The most flashes are negative in the thunderstorms, and the positive and negative leaders’ channel projections are located in the slight precipitation area where the leading edge of heavy precipitation area is. The lightning rarely occurs in the heavy precipitation area. The enhanced convection enlarges the precipitation area and increases the precipitation intensity.(2)The amount of liquid precipitation is much more than solid precipitation. There is an order of magnitude difference between the solid RPF and liquid RPF. The growth rates of liquid and solid precipitation are cloze. The fit lines of RPF and lightning are linearly decreasing. The more lightning happen in the unit time, the less RPF values are. The relationship between solid precipitation and lightning can be made use of lightning forecast, because solid RPF is much more relative to lightning than liquid RPF. The results of this paper offer a further understanding of the relationship of lightning and precipitation, and also suggest a new thought of lightning forecast.(3)The micro-physics processes like collection and convert of ice phased particles lead to more lightning. With the development of convection, the updraft is increasing and more ice phased particles are generated, which is resulting in the more active micro-physics processes. Once the disturbance potential temperature reaches the thresholds value, the intensive updraft bring the ice phased particles to a much more height, thus the collection and convert processes reduce, and lighting numbers are decreasing. As solid precipitation, a large number of hails still generate, so that the solid precipitation increases continuously.(4)The electric fields variations coincide with lightning. The accumulation of solid precipitation may lead intensive change of electric field. Continuous solid precipitation influences the charge structure in the lower part in thunderstorms. The terminal velocity of the particles of hydrometeors is impacted by the intensity of precipitation and electrification both. Because of the re-distribution of charges after the discharge, the terminal velocity of the solid particles which carry more charges changes and becomes faster with the convection and electric force.