摘要
利用1979~2013年NCEP/NCAR月平均再分析资料及NOAA研究中心的CMAP（CPC Merged Analysis of Precipitation）月平均降水资料,通过定义欧亚—北太平洋间大气质量迁移指数IMAMEP,分析了春季欧亚—北太平洋上空大气质量迁移（MAMEP,Migration of Atmospheric Mass over Regions between Eurasia and North Pacific）的年际变化规律及其与同期中国气候异常的联系。结果表明：在北半球中高纬度存在一个纬向分布的欧亚—北太平洋遥相关型,且其可能对中国同期气候异常的形成具有重要影响。春季MAMEP指数具有显著的长期趋势,同时还具有2~4年及5~7年的振荡周期及明显的年代际变化特征。垂直环流和波动运动对欧亚—北太平洋间大气质量迁移具有重要作用。大气质量在欧亚西部低层异常辐合,高层异常辐散,在中、西太平洋地区低层异常辐散,高层异常辐合,在纬向上构成了顺时针的垂直环流圈,将西北太平洋地区的大气质量变动与欧亚大陆上空的变动联系了起来。另外,来自西欧大陆的波扰能量可传播至北太平洋,有利于这些区域上空位势高度异常扰动的维持。IMAMEP与春季同期降水及地表气温异常关系密切。IMAMEP为正时,东亚以北地区、鄂霍次克海西岸以及西欧沿岸降水显著减少,欧亚西部及我国华北地区降水显著增加。850 h Pa上西伯利亚受反气旋式环流控制,太平洋上空受气旋式环流控制,引起欧亚大陆北部地表显著增温,西伯利亚以东、我国东北、华北—江淮地区及韩国、日本南部地表显著降温。西欧—我国西北部分地区大面积显著降温现象与这两个地区受异常反气旋东侧的偏北气流影响有关。这些结果有利于人们更深刻认识区域春季气候异常形成机理。
Using the NCEP/NCAR monthly mean reanalysis and CMAP（CPC Merged Analysis of Precipitation） precipitation data for the period from 1979 to 2013, the authors define an index of the Migration of Atmospheric Mass over Regions between Eurasia and North Pacific（IMAMEP） to investigate the interannual variability of spring MAMEP and its impacts on climate anomalies over China. Our results demonstrate that spring MAMEP is mainly characterized by a seesaw-like structure in surface air pressure anomalies, which can also be referred to as Eurasia–North Pacific teleconnection pattern. The IMAMEP varies with a remarkable long-term trend and periodicities of 2–4 years and 5–7 years as well as distinct interdecadal changes. It is found that an anomalous vertical circulation behaves like a bridge linking Eurasia and North Pacific with the migration of atmospheric mass between these two regions. The atmospheric mass fluxes anomalously converge in the lower troposphere and diverge in the upper troposphere in the west of Eurasia. However, the opposite situations are observed in the western and central Pacific. The wave activity fluxes show that the wave energy propagates eastward from western Europe into the North Pacific, facilitating the maintenance of the anomalous geopotential height disturbances there. In the spring, the IMAMEP is highly correlated with anomalous rainfall and surface air temperature over China. When the IMAMEP is positive, precipitation decreases significantly over the north of East Asia, the west of Okhotsk Sea, and the coastal western Europe, as opposed to the increase over the west of Eurasia and the north of China. The anticyclonic circulation in Siberia and the cyclonic circulation in North Pacific in the lower troposphere induce the anomalously high surface air temperature in northern Eurasia, along with the anomalously low temperature in the east of Siberia, Northeast China, North China, Yangtze–Huaihe River valley, Korea, and the south of Japan. The surface air temperature anomalously decreases in much of western Europe and northwestern China. These results are helpful for us to better understand the formation mechanisms for anomalous climate conditions in Eurasia and North Pacific regions in boreal spring.
出处
《大气科学》
CSCD
北大核心
2016年第6期1261-1272,共12页
Chinese Journal of Atmospheric Sciences
基金
国家自然科学基金项目41175062
公益性行业(气象)科研专项GYHY201406024~~
关键词
大气质量迁移
欧亚—北太平洋遥相关
气候异常
春季
中国
Migration of atmospheric mass
Eurasia–North Pacific teleconnection pattern
Climate anomalies
Spring
China
