The summertime annular mode in the Northern Hemisphere and its linkage to the winter mode
The summertime annular mode in the Northern Hemisphere and its linkage to the winter mode
复制标题
DOI：
10.1029/2004jd004514
复制
发表时间：
2004-10
影响因子：
--
通讯作者：
M. Ogi;K. Yamazaki;Y. Tachibana
中科院分区：
文献类型：
--
作者：
M. Ogi;K. Yamazaki;Y. Tachibana
[1]通过对各月纬向平均位势高度场的经验正交函数分析，研究了北方半球环状模（NAM）的季节变化。冬、夏季NAM不仅在位势高度场上存在差异，而且在平均纬向环流和涡度结构上也存在差异。夏季NAM的纬向尺度较小，与冬季NAM相比向极移。夏季NAM低纬侧的波腹位于冬季NAM的波节纬度上。夏季NAM比原来的北极涛动与欧亚大陆地面气温的关系更密切。夏季NAM是一种由定常波和瞬变波共同维持的波驱动的大气内部模态。夏季NAM与北极锋、极地急流和北冰洋风暴轴有关。M. Ogi等人的理论可以解释为从冬季环形模的一个极性到夏季环形模的相同极性的优选转变。春季冰冻圈，即，欧亚大陆的雪和巴伦支海的海冰在这一转变中起着支持作用。索引术语：1620全球变化：气候动力学（3309）; 3309气象学和大气动力学：气候学（1620）; 3319气象学和大气动力学：大气环流; 3349气象学和大气动力学：极地气象学;关键词：北方半球的环形模式，北极涛动，冬夏联系
[1] The seasonal variations of the Northern Hemisphere annular mode (NAM) are investigated through empirical orthogonal function analysis of the zonally averaged geopotential height fields for each individual calendar month. Patterns of the winter and summer NAMs differ not only in the geopotential height fields but also in the mean meridional circulation and eddy structure. The summer NAM has a smaller meridional scale and is displaced poleward as compared to the winter NAM. The antinode on the lower-latitude side in the summer NAM is at the nodal latitude of the winter NAM. The summer NAM is more strongly related to surface air temperatures over Eurasia than the original Arctic Oscillation. The summer NAM is a wave-driven internal atmospheric mode that is maintained by both stationary and transient waves. The summer NAM is associated with the Arctic front, polar jet, and storm track around the Arctic Ocean. The winter-to-summer linkage described by M. Ogi et al. can be interpreted as a preferred transition from one polarity of the winter annular mode to the same polarity of the summer annular mode. The spring cryosphere, i.e., snow in Eurasia and sea ice in the Barents Sea, plays a supporting role in this transition. INDEX TERMS: 1620 Global Change: Climate dynamics (3309); 3309 Meteorology and Atmospheric Dynamics: Climatology (1620); 3319 Meteorology and Atmospheric Dynamics: General circulation; 3349 Meteorology and Atmospheric Dynamics: Polar meteorology; KEYWORDS: Northern Hemisphere’s annular mode, Arctic Oscillation, winter-to-summer link