基于观测资料的云系分裂现象分析

摘要

Based on mesoscale ground observation,Doppler radar detection,and satellite cloud figure data,the causes of a cloud split phenomenon were analyzed.Results show that the weak precipitation between two rain bands was caused by the clouds split.Combined reflectivity factors reflected that the northern clouds mainly consist of stratiform clouds,while the southern ones were made up of convective clouds.The ENE movement direction of the northern clouds and the E direction of the southern clouds made the two clouds separate gradually.Through the estimation of pressure gradient force at low level,the northern side prevailed northwesterly and the southern one prevailed southeasterly,which represented the movement direction of the clouds at the bottom roughly.The obvious movement difference of the high and low level gained from radar,the pressure gradient force and terrain blocking effect all made the northern and southern clouds separate and led to independent systems.%根据中尺度地面站网、多普勒雷达和卫星云图资料,对一次云系分裂现象的成因进行了分析,结果表明:两条雨带之间的弱降水是由于云系分裂所导致的;组合反射率因子反映出北支云系以层状云为主,南支云系以对流云为主;北支云系移向是ENE,南支云系移向是E,使得两支云系逐渐分离;通过低层气压梯度力的估算,北侧为西北风,南侧为东偏南风,大体代表云系底部的移向,结合雷达得到的高低层明显的移向差异,故引起南支云系和北支云系的逐步分开;受气压梯度力和地形阻挡的作用,使得南北云系分开,成为分别独立的云系.