On the extratropical influence of variations of the upper tropospheric equatorial zonal mean zonal wind during boreal winter
On the extratropical influence of variations of the upper tropospheric equatorial zonal mean zonal wind during boreal winter
复制标题
DOI：
10.1175/jcli-d-14-00185.1
复制
发表时间：
2015
影响因子：
4.9
通讯作者：
G. Gollan;R. Greatbatch
中科院分区：
文献类型：
--
作者：
G. Gollan;R. Greatbatch
摘要利用月平均的旋转经验正交函数研究了北半球冬季全球对流层纬向风的变化[U]。前两个模态对应于南北环模态，模态3和4代表热带的变率。一个与厄尔尼诺-南方涛动有关，另一个与5°N - 5°S [U150]E之间150 hPa [U]时间序列高度相关，并与Madden-Julian涛动的活动有关。利用500 hpa位势高度对[U150]E时间序列的线性回归研究了对[U150]E的温带响应。利用了再分析数据和使用欧洲中期天气预报中心模式的弛豫实验的总体平均输出，其中热带大气对再分析数据是弛豫的。回归分析表明，阿留申低压的移动和横跨北大西洋的波列是主要原因。
AbstractVariations in the global tropospheric zonal-mean zonal wind [U] during boreal winter are investigated using rotated empirical orthogonal functions applied to monthly means. The first two modes correspond to the northern and southern annular mode and modes 3 and 4 represent variability in the tropics. One is related to El Nino–Southern Oscillation and the other has variability that is highly correlated with the time series of [U] at 150 hPa between 5°N and 5°S [U150]E and is related to activity of the Madden–Julian oscillation. The extratropical response to [U150]E is investigated using linear regressions of 500-hPa geopotential height onto the [U150]E time series. Use is made of reanalysis data and of the ensemble mean output from a relaxation experiment using the European Centre for Medium-Range Weather Forecasts model in which the tropical atmosphere is relaxed toward reanalysis data. The regression analysis reveals that a shift of the Aleutian low and a wave train across the North Atlantic are ...