基于L波段探空观测的FY-4A云顶温度产品评估及其在冬季降水相态判识中的应用  

Evaluation of FY-4A Cloud Top Temperature Product Based on L-Band Radiosonde Data and Its Application in Winter Precipitation Type Identification

作　　者：赵渊明 孙静[2] 漆梁波[1] 张燕燕 ZHAO Yuanming;SUN Jing;QI Liangbo;ZHANG Yanyan(Shanghai Central Meteorological Observatory,Shanghai 200030;Tsinghua University,Beijing 100084;Baoshan Meteorological Office of Shanghai,Shanghai 201901)

机构地区：[1]上海中心气象台,上海200030 [2]清华大学,北京100084 [3]上海市宝山区气象局,上海201901

出　　处：《气象》2024年第1期59-70,共12页Meteorological Monthly

基　　金：上海市自然科学基金项目(21ZR1462700)资助。

摘　　要：利用2019—2021年冬季上海宝山站L波段探空资料对FY-4A云顶温度(CTT)产品进行评估,分析发现,FY-4A的云顶温度产品能够较好地反映单层云的云顶温度,对双层云或多层云的云顶温度则普遍高估(平均高估幅度超过14℃);当探空观测到的云顶高度不超过6 km或云顶温度不低于-20℃时,FY-4A云顶温度产品误差较小,平均偏差约为3℃。根据2021—2022年冬季长三角地区地面站观测的降水现象统计云顶温度与降水相态的关系,并对典型个例进行分析,结果表明,云顶温度低是出现降雪的必要条件之一,绝大部分降雪出现在云顶温度低于-12℃的情况下。FY-4A的云顶温度产品时空分辨率高、精度尚可,可以辅助预报员判识雨雪落区,在雨雪转换过程的预报服务中有较大的应用潜力。By using the L-band radiosonde data of Shanghai Baoshan Station during the winter from 2019 to 2021,the FY-4A cloud top temperature(CTT)product is evaluated.The results indicate that the CTT of the single-layer cloud can be reflected well by the FY-4A CTT product,while the CTT of multi-layer clouds is generally overestimated with the mean bias larger than 14℃.And the FY-4A CTT product has a small mean bias of approximately 3℃compared to the sounding observation when the observed cloud top height is below 6 km or the observed cloud top temperature is higher than-20℃.Moreover,based on the surface observation in the Yangtze River Delta Region in the winter of 2021 and 2022,the relationship between CTT and precipitation types in winter seasons is statistically analyzed and further verified by typical cases.The results reveal that a low CTT is one of the main necessary conditions for snowfall,as most snowfall events occur when the CTT is below-12℃.As the FY-4A CTT product has a certain accuracy with a high spatial and temporal resolution,this product could have great application potential in iden-tifying precipitation types.

关 键 词：秒级探空 FY-4A 云顶温度产品 降水相态 冬季 

分 类 号：P457[天文地球—大气科学及气象学] P412