摘要
利用宁夏1970-2003年沙尘暴时序资料,结合NCEP/NCAR月平均全球再分析和逸出长波幅时(OLR)月平均资料,对宁夏春季(3-5月)沙尘暴多发年和少发年高低层高度场和纬向风剖面场以及OLR场的差异特征进行了合成对比诊断分析。结果表明:不同时期的春季,宁夏沙尘暴多发或少发与位势高度场和急流区的位置及强度密切相关。沙尘暴多发年,500hPa蒙古西部到河西为较强的负距平区,200hPa急流区位于河套北部;沙尘暴少发年,高层负距平区及急流区位置明显偏北、偏东。不仅如此,中低纬度的青藏高原及西太平洋地区OLR的不同分布与宁夏沙尘暴多发或少发也有明显的对应关系,沙尘暴多发年,贝加尔湖到河套地区为负距平区,青藏高原以正距平为主,西太平洋地区也基本为正距平;而沙尘暴少发年,OLR则呈相反分布。
Using the sandstorm data of Ningxia in 1970- 2003 ,the global monthly mean NCEP/NCAR reanalyzed data and the monthly mean OLR, the comparative diagnostic analysis of the height fields in high and low level, the cross fields of zonal flow and the difference of OLR field for the sandstorm freguently and rarely occurring years in Ningxia in spring （March-May） was conducted. Results show that the positions and intensity of geopotential height fields and the number of sandstorms is closely related. In the year with more sandstorms, there is a negative anomaly area at 500hPa height field in Mongolia and west part of Hexi, jet at 200hPa locates in north of Hetao, and in the area of Bekal Lake there is a negative OLR anomaly and positive anomaly in Qinghai-Tibet plateau and west Pacific. While in the year with fewer sandstorms, the positions of jet and negative anomaly are obvious northerliness and easterliness, and the OLR is opposite to that in the year with more sandstorms.
出处
《自然灾害学报》
CSCD
北大核心
2008年第4期59-65,共7页
Journal of Natural Disasters
基金
国家自然科学基金项目(40575048)
宁夏自然科学基金项目(AD001-2004)
关键词
沙尘暴
环流
OLR
分析
sandstorm
circulation
OLR
analysis
