利用NCEP再分析资料和新一代天气雷达资料对干旱区一次持续阴雪天气的分析研究

摘要/Abstract

摘要： 利用NCEP再分析资料和银川新一代天气雷达资料,对2008年元月中下旬宁夏持续阴雪极端天气进行了环流背景及雷达回波特征分析。分析表明:欧洲阻高的建立与崩溃、里海到巴湖切断低压的维持加深与减弱、东亚大槽的稳定维持、副高的偏北偏强及高原东侧西南气流的存在,为宁夏持续阴雪天气提供了有利的环流背景及较好的水汽条件,低层辐合、高层辐散为降雪天气提供了持续的上升运动,而低层高原低值系统的作用,是造成局地大降雪的主要原因。降雪雷达回波强度一般维持在10～25 dBz,超过30 dBz的回波面积小,回波顶比较平整,顶高普遍在4.0～6.0 km,最高达到7.0 km左右,零速度线有时可表现为明显的 “S”型结构;利用Z-I关系进行雷达定量降水估测对降雪有一定的反演能力。

关键词: 持续阴雪, 多普勒雷达, 定量估测降水, 干旱区

Abstract: Based on NCEP reanalyzed data and Yinchuan Doppler Radar data, the circulation background and the characteristics of radar echo of a continual cloudy-snowy weather in Ningxia occurred in the second and last ten-day period in January 2008 was analyzed. The result shows that: the formation and collapse of European blocking high, the maintaining and strengthening and weakening of the cut-off low between the Caspian sea and Balkhash Lake, the stability maintaining of trough in East Asia, the north border of subtropical high is northward and stronger than the normal, and the existence of south-west air-flow over the east Qinghai-Tibet plateau, have provided advantageous circulation background and water vapor condition for the continuance of Ningxia cloudy-snowy weather; the low level convergence and high level divergence have provided persistent ascending motion for snowy weather; nevertheless, the low-level Low-Pressure Systems over Tibetan plateau is the main cause of local-scale heavy snow. The echo reflectivity of snow is usually around 10~25 dBz, area of echo with reflectivity over 30 dBz is small, the echo's top looks smooth and is around 4.0~6.0 km, the max echo top reaches to 7 km, the zero velocity belt sometimes appears as an distinct "S"; the Z-I relationship can be used to estimate the snowfall at a certain extent.

Key words: cloudy-snowy weather, Doppler Weather Radar, quantitative estimation, precipitation, arid area

中图分类号:

P458

纪晓玲;冯建民;陈晓娟;徐阳春;穆建华;赵蔚. 利用NCEP再分析资料和新一代天气雷达资料对干旱区一次持续阴雪天气的分析研究[J]. 中国沙漠, 2010, 30(2): 432-438.

JI Xiao-ling;FENG Jian-min;CHEN Xiao-juan;XU Yang-chun;MU Jian-hua;ZHAO Wei. Study of a Continual Cloudy-snowy Weather in Arid AreaUsing NCEP Reanalyzed Data and Doppler Radar Data[J]. JOURNAL OF DESERT RESEARCH, 2010, 30(2): 432-438.

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