The Study Of Numerical Simulation On The Charge Structure During Two Thunderstorms In Qinghai

According to the observation and analysis,it is inferred that most of the thunderstorms in the Plateau have a tripolar charge structure,with a large lower positive charge region at the bottom.However,there is no evidence to show that the upper positive charge region of the special type of thunderstorm cloud in the inland Plateau of China participates in the discharge.Is the charge structure of the thunderstorm a reverse polar structure,a tripolar structure with a large subpositive region at the bottom,or a tripolar structure with a large lower positive charge region at the bottom and without obvious dominant positive region at the top? In order to further understand the formation of the plateau area charge structure and the characteristics of the structure in this paper,the three-dimensional thunder cloud power-electricity coupling mode to chase in Qinghai region on July 29,2011 and August 10,2013 and two analysis to simulate the process of thunderstorms,charge structure characteristics of the Qinghai plateau region are analyzed and the characteristics of lightning leader,and from water vapor flux upward,source of water and ice phase particles than these physical aspects analyzes its main reasons.The results showed that:(1)As the ambient temperature is low in the region,it is difficult for the weak updraft to continuously transport enough water vapor upward,and liquid precipitation will form after reaching a certain height,which will be cut off by the downdraft.Moreover,the overall height of the thunderstorm cloud is also low,and the convective cloud will dissipate quickly.When the updraft is weak,the life cycle of the thunderstorm is short.When there is strong wind shear in the lower layer,the ground convergence is enhanced,which can continuously transport water vapor,and the cold outflow can lift the central heating current,which is conducive to the formation of multi-monomer.(2)The amount of ice and snow particles generated mainly affected by water vapor,no matter how strong updraft,ice and snow particle rely mainly on increasing moisture formula,but the updrafts weak when ice crystals will be automatically converted into more snow particles,there will be more strong updraft when ice crystals into graupel particles,mainly with the cloud droplets,rain water and ice frozen,mainly consumes than the water content of cloud droplets,ice phase particles under the strengthening of rising wind speed,they quality produce rate will increase fast,have bigger influence on the height of its distribution.(3)The development characteristics of thunderstorm charge structure in Qinghai: During the formation of weak updraft of thunderstorm clouds,a negative charge structure is formed in the middle of the cloud first,and the charge density of the two charge areas is relatively high,and the negative charge area may be formed in the warm cloud.With the strengthening of the updraft,the ice crystals and snowflakes rise to a higher place,and the upper part of the thunderstorm cloud forms a strong positive charge area,which forms a tripolar structure.The main positive charge area and negative charge area are both deep,while the lower positive charge area is weakened,but the range is profound and the time is relatively long.(4)Convection is weak,the wind speed is low,rising clouds are highly constrained,and cloud ice and snow particle number concentration in the central,under a certain EWLC,after the size of particle collision,small ice and snow are negatively charged particles,and big graupel particles are positively charged,while the snow particle distribution center under the center of the ice crystal particles,also can form and charge structure similar to that of ice crystal particles.By the development of convective clouds,rising speed enhancement,ice crystals in the cloud particles will begin to rise,in the role of the inductive electrification mechanism,the upper part of positive charge area formed part of the ice and snow lotus positively charged particles,the cloud in the middle of a negative charge area formed by part graupel particles and ice crystals burden electricity,and graupel lotus positively charged particles to form a positive charge at the bottom of the cloud area.In the case of non-inductive electrification,the inductive electrification strengthens the positive charge region at the bottom and negative charge region in the middle,and the charge density of cloud droplets plays a certain role in strengthening the charge structure.