春季西亚地表热力异常与初夏东北冷涡活动年代际变化的联系

基于1979~2015年中国月平均站点温度资料，计算了初夏东北冷涡指数，分析了初夏东北冷涡活动的年代际变化特征。在此基础上，进一步探讨了东北初夏冷涡活动与春季西亚地表热力异常之间的可能联系，并初步讨论了前期西亚地表热力异常影响东北初夏冷涡活动的可能过程。结果表明:（1）1979~2015年间，初夏东北冷涡强度表现出明显的年代际变化特征，2000年前，冷涡活动总体偏强，之后总体减弱。（2）春季西亚地表热力状况在2000年前后也发生了明显的年代际转变:2000年前总体偏冷，之后明显偏暖。（3）春季西亚地区的地表热力异常与东北冷涡活动的在年代际尺度上联系密切。西亚地表异常偏冷，东北冷涡活动偏强；而西亚地表异常偏暖对应了偏弱的冷涡活动。初步分析发现，西亚地表热力因子可能通过影响大气环流分布并通过遥相关型影响我国初夏东北地区冷涡，当然相关的机理还有待深入分析。

Connection between Spring Land Surface Thermal Anomalies over West Asia and Decadal Variation of Early Summer Cold Vortex in Northeast China

The cold vortex index in Northeast China is calculated by using the monthly station temperature data during 1979-2015 provided by the National Climate Center of China.In the present study,basic features of the cold vortex activity variation and its possible linkage with the springtime land surface thermal condition over west Asia are investigated.Results are as follows:(1) The intensity of the cold vortex in Northeast China displays a significant decadal fluctuation and an obvious decadal transition from positive phase (strong cold vortex) to negative (weak cold vortex) phase around 2000.(2) Decadal variation is also found in springtime land surface thermal condition over West Asia.The land surface was relatively cold before 2000 but became warm since then.(3) There is a close relationship between the decadal variations in early summer cold vortex and spring land surface thermal condition,i.e.,cold (warm) land surface corresponds to intensified (weakened) cold vortex.Further analysis suggests that anomalous land surface thermal forcing can result in abnormal general circulation and affect the cold vortex activity via the atmospheric teleconnection.However,the related physical mechanism needs further investigation in the future.