基于NCEP资料的近30年夏季青藏高原低涡的气候特征  

Analysis of 30-Year Climatology of the Tibetan Plateau Vortex in Summer with NCEP Reanalysis Data

作　　者：李国平[1] 赵福虎 黄楚惠[3] 牛金龙 

机构地区：[1]成都信息工程学院大气科学学院,成都610225 [2]重庆市气象台,重庆401147 [3]四川省气象台,成都610072 [4]成都市气象局,成都610072

出　　处：《大气科学》2014年第4期756-769,共14页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金项目41175045;91337215;国家重点基础研究发展计划(973计划)项目2012CB417202;公益性行业(气象)科研专项GYHY201206042

摘　　要：基于NCEP/NCAR再分析资料并通过人工识别与天气图对比,本文对1981～2010年夏季高原低涡的气候特征进行了统计分析,对比研究了高原低涡高发年和低发年的大气环流场和低频分量场的特征,主要结果有：（1）近30年来夏季高原低涡平均每年生成32个,低涡发生频数呈现较明显的增多趋势,并具有较强的年际变化特征,低涡频数在2000年和2005年出现显著突变,在2000年由增多趋势转为减少趋势,在2005年又转为增多趋势,同时低涡频数具有显著的准5年、准9年和准15年周期振荡,6月生成的高原低涡呈减少趋势,而7月和8月生成的高原低涡均呈现增多趋势;（2）夏季高原低涡生成源地主要集中在西藏双湖、那曲和青海扎仁克吾一带,其中高原中部涡占50.8％,西部涡占27.0％,东部涡占22.2％,6月、7月和8月生成的高原低涡分别占夏季低涡总数的44.7％、29.9％和25.4％,高原低涡生成时绝大多数为暖性涡,占总数的90.7％.近30年来平均每年夏季有1.3个高影响高原低涡移出高原并在下游大范围地区产生强降水天气;移出的高原低涡以东移为主,占移出高原低涡的56.4％,而东北移和东南移的分别占移出高原低涡的20.1％和20.5％;（3）高原低涡高发年,低层的大气环流场和低频大气环流分量场均表现出较强的水平辐合及偏南气流,高层的青藏高压在高原主体范围内较气候态偏强;高原低涡低发年的情况则与之相反,伊朗高原上空的气旋、青藏高原低槽和高原南侧反气旋的配置对高原低涡的发生具有重要作用.On the basis of National Centers for Environmental Prediction/National Center for Atmospheric Research （NCEP/NCAR） reanalysis data, and through artificial identification and comparison of weather maps, the climatic characteristics of the Tibetan Plateau Vortex （TPV） in summers of 1981 to 2010 are analyzed in this paper, and the characteristics of the atmospheric circulation and low-frequency component field are comparative studied in high- and low-frequency years of the TPV, respectively. The main results are summarized in the following points： （1） During the past 30 years, 32 TPVs were generated over the Tibetan Plateau in summer, and the occurrence frequency of the TPV presents an obvious increasing trend and a strong interannual variability. The vortex frequency appears as significant mutations in 2000 and 2005, shifts from an increasing trend to decreasing trend in 2002, and converts into a growing trend in 2005. Moreover, the vortex frequency has significant potential for quasi-periodic oscillations to occur in periods of approximately 5, 9, and 15 years. The TPV frequency generated in June shows a decreasing trend that increase in July and August. （2） The generating sources of the TPV in summer appear mainly in the regions of Shuanghu and Nagqu in Tibet and Zarenkewu in Qinghai in the central, western, and eastern plateau respectively accounting for 50.8%, 27.0%, and 22.2% of the total. The TPVs in summer generated in June, July, and August respectively account for 44.7%, 29.9%, and 25.4% of the total. The warm TPVs in summer make up the vast majority, accounting for 90.7% of the total. About 1.3 TPVs could develop strongly and move out of the plateau every summer during the past 30 years, which produce heavy rainfall in a wide range of downstream areas. The TPVs moving out of the Tibetan Plateau with east, northeast, and southeast shifting accounted for 56.4%, 20.1%, and 20.5%, respectively. （3） During the high-incidence years of TPV, the atmospheric circulation and low-frequency c

关 键 词：青藏高原 高原低涡 气候特征 低频振荡 

分 类 号：P443[天文地球—大气科学及气象学]