摘要
本文利用１９９８年“淮河流域能量与水份循环试验（ＨＵＢＥＸ）”所获得 的大量雷达资料及遥测雨量计资料，细致分析了淮河流域梅雨锋云系的结构。根据 层状云和对流云在雷达回波图中的不同特征，本文提出用松散系数Ｄ（反映云系结 构疏松程度）来区分大范围云带中的降水云类型。由５２９张ＰＰＩ资料统计表明，若 Ｄ＞０．１７则说明该云区结构松散，降水属于层状云降水，Ｄ≤０．１７时，云区是对流 性降水。 由于梅雨锋降水具有明显的不均匀结构特征，其中锋面对流云带和强下挂回 波带是造成强降水的主要原因。在用地面雨量计资料和雷达资料对地面降水进行 短时（３小时以内）校正时，针对不同的降水类型采用不同的Ｚ～Ｒ关系比用同一种 Ｚ～Ｒ关系的校正精度大约提高４％。
We analyze the structure of precipitation cloud system in Mei-yu front,and we propose an identification factors for distinguishing strait form and convective precipitation among the stratiform cloud system of the large area precipitation. The identification factor is Looseness coefficient D,statistics show that it is a convective precipitation when D>0. 17, otherwise it's strait form. Research of radar data and associated raingauge data from June 29 to July 2 shows that the contributions of convective and hang down echo precipitation varies from 60% on 1 July to 73% on 29 June,but the echo area coverage was less than 40%. For this reason,the con- vective and hang down echo precipitation are the main contributions for Mei-yu front precipi- tation. Considering in the calculation of surface radar-based rainfall accumulation within the three hours,a distinct Z-R relationship is required for the different precipitation type, the accuracy on the calibrated radar rainfall estimation raises about 4% than using single Z-R relation.
出处
《气象科学》
CSCD
北大核心
2001年第1期9-18,共10页
Journal of the Meteorological Sciences
基金
国家自然科学基金资助项目"淮河流域能量和水份循环试验和研究(HUBEX)"!(项目批准号49794030)
关键词
松散系数D
降水校正
梅雨锋
降水云系
雷达回波
对流回波
层状回波
Distinguishment of straitform and convective clouds Looseness coefficient Calibration of precipitation
