摘要:本文利用计算机客观识别技术，稳定地识别出高原切变线并分析了高原切变线的气候特征。通过对比三套常用的高分辨率再分析资料（ERA-Interim、NCEP CFSR和JRA-55）在高原地区中低层大气的适用性，筛选出与高原地区500 hPa风场较为吻合的NCEP CFSR（National Centers for Environmental Prediction Climate ForecastSystem Reanalysis）再分析资料作为基础数据，根据人工判识切变线的基本标准与计算机几何学知识，定义了高原切变线的客观识别标准。对客观识别出的2005~2015年高原切变线与《青藏高原低涡切变线年鉴》中的结果进行对比分析与验证，并在此基础上统计分析了近11年高原切变线的气候特征。高原切变线年均生成49.4条，其中东部型切变线年均38条，是高原切变线的基本型；高原切变线维持时间多为6 h；切变线两侧的水平散度、垂直涡度和总变形三个物理量的大值区均出现在94°~95°E。客观识别高原切变线的方法可以较为高效地识别高原切变线，为高原切变线研究提供了新的途径。
关键词:高原切变线/
客观识别/
CFSR再分析资料/
时空分布/
气候特征
Abstract:This study aims to objectively and efficiently identify the TPSL (Tibetan Plateau shear line) and analyze the climatic characteristics of the TPSL. Based on comparison of the applicability of three high resolution reanalysis datasets (ERA-Interim, NCEP CFSR, and JRA-55) commonly used in the Tibetan Plateau area, the CFSR reanalysis dataset is selected as the basic dataset. According to the basic standard for manual identification of shear line and knowledge of computer geometry, an objective identification standard for TPSL is determined. The objectively identified TPSLs during 2005-2015 are compared with the TPSLs shown in the Tibetan Plateau Vortex and Shear Line Yearbook. On the basis of the comparison and verification, climatic characteristics of the TPSL in the recent 11 years are statistically analyzed. The annual average number of TPSLs is 49.4, among which 38 are eastern-type, which is also the basic type of TPSL. The maintenance time of the TPSL is 6 h usually. Areas of large total deformation, vertical vorticity, and horizontal divergence all are located between 94°-95°E. The objective TPSL identification method can efficiently identify the TPSL, and provides a new way to study the TPSL.
Key words:Tibetan Plateau shear line/
Objective identification/
CFSR reanalysis dataset/
Spatiotemporal evolution/
Climatic features
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