Persistent Circulation Regimes and Preferred Regime Transitions in the North Atlantic
Persistent Circulation Regimes and Preferred Regime Transitions in the North Atlantic
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DOI：
10.1175/jas-d-11-046.1
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发表时间：
2011-12-01
影响因子：
3.1
通讯作者：
Martius, Olivia
中科院分区：
文献类型：
--
作者：
Franzke, Christian;Woollings, Tim;Martius, Olivia
研究了北大西洋上空涡旋驱动的急流的持续状态行为。1957年12月1日至2002年2月28日40年ECMWF再分析（ERA-40）资料中对流层低层最大风速的纬度是北大西洋急流变率的特征。隐马尔可夫模型（HMM）分析显示，急流表现出三种持续状态，分别对应于北部、南部和中部急流状态。这些状态与北大西洋涛动和东大西洋遥相关型密切相关。这些状态与风暴路径的明显变化以及气旋和反气旋罗斯比破波的发生频率有关。确定了三种优先的状态转换，即南部到中部急流、北部到南部急流和中部到北部急流。这种优先转换可以解释为对急流向极地传播的偏好，但通过从北部状态的戏剧性转变进入南部急流状态。有证据表明，波浪破碎参与了三个优先转换中的两个（北部到南部急流和中部到北部急流）。本文还讨论了气候变化的可预测性特征和年际变化。
The persistent regime behavior of the eddy-driven jet stream over the North Atlantic is investigated. The North Atlantic jet stream variability is characterized by the latitude of the maximum lower tropospheric wind speed of the 40-yr ECMWF Re-Analysis (ERA-40) data for the period 1 December 1957-28 February 2002. A hidden Markov model (HMM) analysis reveals that the jet stream exhibits three persistent regimes that correspond to northern, southern, and central jet states. The regime states are closely related to the North Atlantic Oscillation and the eastern Atlantic teleconnection pattern. The regime states are associated with distinct changes in the storm tracks and the frequency of occurrence of cyclonic and anticyclonic Rossby wave breaking. Three preferred regime transitions are identified, namely, southern to central jet, northern to southern jet, and central to northern jet. The preferred transitions can be interpreted as a preference for poleward propagation of the jet, but with the southern jet state entered via a dramatic shift from the northern state. Evidence is found that wave breaking is involved in two of the three preferred transitions (northern to southern jet and central to northern jet transitions). The predictability characteristics and the interannual variability in the frequency of occurrence of regimes are also discussed.