The Relationship between Northern Hemisphere Winter Blocking and Tropical Modes of Variability
The Relationship between Northern Hemisphere Winter Blocking and Tropical Modes of Variability
复制标题
北半球冬季阻塞与热带变率模式之间的关系
DOI：
10.1175/jcli-d-16-0742.1
复制
发表时间：
2017
影响因子：
4.9
通讯作者：
R. Greatbatch
中科院分区：
文献类型：
--
作者：
G. Gollan;R. Greatbatch
本文研究了一些主要的热带变率模态对北半球冬季北方区域阻塞频率变率的影响，并将给出最重要的结果。再分析
数据和ECMWF模式的实验使用松弛对ERA-40再分析数据内的热带。研究的热带模态有厄尔尼诺南方涛动（ENSO）、马登-朱利安涛动（MJO）和对流层上层赤道纬向平均纬向风（U150）。将这些热带模态对阻塞频率的影响与北大西洋涛动（NAO）和北太平洋涡旋涛动（NPGO）这两个热带外模态的影响进行比较，发现热带模态的影响幅度相当。对欧洲-大西洋区域的分析表明，冷ENSO事件、MJO位相的晚期以及MJO位相的抑制都导致中低层阻塞频率的增强
纬度（北纬48度以南）每周到每月的时间尺度。在欧洲高纬度地区（北纬48度以北），与ENSO和MJO相关的阻塞异常比低纬度地区不那么明显。相反，在高纬度地区（北纬48度以北），西风（东风）相的U150与减少（增强）阻塞频率。
The influence of some major tropical modes of variability on northern hemisphere regional blocking frequency variability during boreal winter is investigated and the most important findings will be presented here. Reanalysis
data and an experiment with the ECMWF model using relaxation towards the ERA-40 reanalysis data inside the tropics are used. The tropical modes under investigation are El Nino Southern Oscillation (ENSO), the Madden-Julian Oscillation (MJO) and the upper tropospheric equatorial zonal-mean zonal wind (U150). Comparing the impact on blocking frequency of these tropical modes with the impact of two extratropical modes, namely the North Atlantic Oscillation (NAO) and the North Pacific Gyre Oscillation (NPGO), it is found that the tropical influence is of comparable amplitude. Focusing on the Euro-Atlantic sector, it is found that cold ENSO events, late MJO phases, as well as suppressed MJO are all leading to enhanced blocking frequency at lower to middle
latitudes (south of 48N) on weekly to monthly timescales. At higher latitudes (north of 48N) over Europe, the blocking anomalies associated with ENSO and the MJO are less clear than at lower latitudes. Instead, at higher latitudes (north of 48N), the westerly (easterly) phase of U150 is associated with reduced (enhanced) blocking frequency.
影响因子：
3.1
作者：
P. Berrisford;B. Hoskins;E. Tyrlis
通讯作者：
P. Berrisford;B. Hoskins;E. Tyrlis
影响因子：
4.9
作者：
Bell, C. J.;Gray, L. J.;Scaife, A. A.
通讯作者：
Scaife, A. A.