西北地区东部沙尘暴转型的环流演变及差异特征分析  

Circulation evolvement and its diversity characteristics at the transition period of sandstorm occurrence frequency at the east part of Northwest China

作　　者：陈楠[1] 陈豫英[1] 范小明 赵光平[1,3] 彭维耿 

机构地区：[1]宁夏气象防灾减灾重点实验室,宁夏银川750002 [2]固原市气象局,宁夏固原756000 [3]中国气象局兰州干旱气象研究所,甘肃兰州730020 [4]民航银川空中交通管理站技术保障部,宁夏银川750011

出　　处：《干旱区地理》2010年第5期676-683,共8页Arid Land Geography

基　　金：国家自然科学基金(40965008;41075069;40575048);宁夏自然科学基金(NZ09200和NZ08158)共同资助

摘　　要：利用西北地区东部近50 a较完整的沙尘暴资料序列,结合同期NCEP/NCAR全球月平均再分析资料,研究了西北地区东部沙尘暴过程发生频次的年际变化,重点揭示了西北地区东部沙尘暴转型(过程发生频次由多到少及由少到多)的大尺度环流演变及差异特征。结果表明:西北地区东部沙尘暴过程发生频次在20世纪80年代中期出现明显转型,减少趋势通过了0.01的信度检验,90年代末,沙尘暴频次明显增加,但未通过显著性检验;沙尘暴由多到少转型时,乌拉尔山(简称乌山)到巴尔喀什湖(简称巴湖)附近温度负距平减小,纬向风减弱,经向风明显加强,冷空气强度呈逐渐减弱趋势,贝加尔湖地区到西北地区东部的温度正距平增大,纬向风明显减弱,经向风逐渐加强;位于该区域的高压脊呈逐渐增强趋势;而沙尘暴由少到多转型时,大尺度环流场与由多到少转型相比有明显的差异。Using sequential sandstorm data in recent 50 a at the east part of northwest China,and the NCEP/NCAR global monthly average reanalyzed data at the same period,the yearly variation of sandstorm occurrence frequency at the east part of Northwest China was studied,especially the large scale circulation evolvement and diversity characteristics at the sandstorm transition period（in which the sandstorm occurrence frequency has an evolvement from more to less or from less to more） was revealed.The result indicated that the sandstorm occurrence frequency at the east part of northwest China has an remarkable transition in middle 1980s,the downtrend of sandstorm occurrence frequency passed the degree of confidence test of 0.01;in late 1990s,the sandstorm occurrence frequency increased remarkably,but it did not pass the degree of confidence test;at the transition period sandstorm occurrence times decreased gradually,the intensity of cold air by Ural Mountain and Lake Balkhash put up a downtrend,and the subtractive temperature anomaly decreased,the zonal wind weakened,the meridional wind strengthened.Meanwhile,the high pressure ridge from Baikal Lake area to the east part of northwest China was enhanced,plus temperature anomaly increased,the zonal wind weakened remarkably and the meridional wind strengthened gradually;the large scale circulation at Ural Mountain and the area from Baikal Lake to the east part of northwest China is discrepant remarkably between the two kinds of sandstorm transition periods.

关 键 词：沙尘暴转型 环流 演变 差异特征 

分 类 号：P445.4[天文地球—大气科学及气象学]