雷达拼图资料上中尺度对流系统的跟踪与预报  

Mesoscale Convective Systems(MCSs) Tracking and Nowcasting Based on Radar Mosaic Data

作　　者：杨吉[1,2] 郑媛媛[1,2] 夏文梅[1,2] 徐芬[1,2] 徐坤[3] 

机构地区：[1]江苏省气象科学研究所,南京210009 [2]中国气象科学研究院灾害天气国家重点实验室,北京100081 [3]中国船舶重工集团第七二四研究所,南京210003

出　　处：《气象》2015年第6期738-744,共7页Meteorological Monthly

基　　金：公益性行业(气象)科研专项(GYHY201206042;GYHY201306008和GYHY201306014);灾害天气国家重点实验室开放课题(2014LASW-B01);国家自然科学基金青年科学基金项目(41105023);北极阁基金(BJG201207和BJG201302);江苏省局重点项目(KZ201407)共同资助

摘　　要：在中尺度对流系统(Mesoscale Convective Systems,MCSs)自动识别基础上,利用相关法跟踪雷达回波(Tracking Radar Echoes by Cross-correlation,TREC)和面积重叠法完成新的跟踪预报方法。新方法利用TREC得到MCSs移动矢量,利用该矢量外推对应MCSs雷达回波。根据外推回波与相应回波实况,采用面积重叠法完成跟踪,同时利用移动矢量完成预报。采用4次强天气过程对算法进行检验,分析结果表明:(1)新方法能够有效实现MCSs跟踪与预报;(2)新方法得到MCSs移动速度相对稳定,不因为系统合并、分裂和生消出现速度大幅度波动现象,有效减小预报误差,6~60 min预报误差相对于原方法减小20%以上;(3)新方法虽然能提取得到较为稳定的系统移动速度,但不能得到系统的传播速度。原方法能得到系统的移动速度和传播速度合成,但提取速度不稳定,容易受到质心偏移的影响,预报误差较大。新方法在系统消亡期提取移动速度不稳定,导致跟踪丢失现象的发生,而原方法在系统合并与分裂时易出现跟踪丢失现象。Based on the automatic identification mesoscale convective systems(MCSs),tracking radar echoes by cross-correlation(TREC) and area overlap method(AOM) were used to complete the new tracking and nowcasting algorithm.TREC was used in the new algorithm to get motion vector,then this vector was used to extrapolate radar echoes of corresponding MCSs.According to extrapolation echoes and real-time radar echoes,AOM was used to make tracking,and simultaneously the MCSs nowcasting was completed.The performance of the algorithm was evaluated by applying four different types of severe convection cases.The results demonstrate that the algorithm can make tracking and nowcasting effectively.The speed of MCSs extracted by new algorithm is more stable,and does not fluctuate rapidly due to splitting,merging,developping and decaying.Forecast errors are reduced effectively and 6 — 60 min nowcasting errors are cut more than 20%by using the new algorithm instead of the old one.However,the new algorithm can extract stable moving speed of system,but it can not get propagating speed.The old algorithm can extract the integration of moving speed and propagating speed,but the extracted speed is unstable being easily affected by centroid variation and creating bigger nowcasting errors.The speed extracted by new algorithm is unstable during the dying period,causing the failure of tracking.When using the old algorithm,such failure may happen in the case of splitting or merging.

关 键 词：中尺度对流系统 跟踪 预报 

分 类 号：P412.25[天文地球—大气科学及气象学] P457