The impact of combined ENSO and PDO on the PNA climate: a 1,000-year climate modeling study
The impact of combined ENSO and PDO on the PNA climate: a 1,000-year climate modeling study
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DOI：
10.1007/s00382-007-0267-4
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发表时间：
2007-06
期刊：
影响因子：
4.6
通讯作者：
B. Yu;F. Zwiers
中科院分区：
文献类型：
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作者：
B. Yu;F. Zwiers
这项研究利用加拿大气候模拟与分析中心(CCCma)耦合气候模式长达1000年的积分，分析了大气对太平洋年际ENSO和年代际-年代际PDO变率的响应，重点放在太平洋-北美(PNA)部门。对流层环流和北美温度都表明，当ENSO和PDO变率同步时，类似PNA的气候反应和对北美的影响增强。类PNA模式的作用中心异常明显不同于零，异常模式具有场显着意义。伴随着驻波异常，从北太平洋向下游流向北美的中高纬度出现了较大的驻波活动通量。热带外北太平洋和副热带北太平洋存在明显的Rossby波源异常。此外，太平洋风暴轴随PNA正向南移。与ENSO变化有关的大气加热异常主要局限于热带地区。东北太平洋有一个异常的加热中心，热带太平洋也有同极性的异常，对PDO变率有影响。ENSO和PDO的同相结合又将提供热带太平洋和北太平洋向北美的大气能量异常输送，这有利于驻波异常的发生，并将导致类似PNA的波异常结构。模拟结果也证实了我们基于20世纪的观测记录所做的分析。
This study analyzes the atmospheric response to the combined Pacific interannual ENSO and decadal–interdecadal PDO variability, with a focus on the Pacific-North American (PNA) sector, using a 1,000-year long integration of the Canadian Center for Climate Modelling and Analysis (CCCma) coupled climate model. Both the tropospheric circulation and the North American temperature suggest an enhanced PNA-like climate response and impacts on North America when ENSO and PDO variability are in phase. The anomalies of the centers of action for the PNA-like pattern are significantly different from zero and the anomaly pattern is field significant. In association with the stationary wave anomalies, large stationary wave activity fluxes appear in the mid-high latitudes originating from the North Pacific and flowing downstream toward North America. There are significant Rossby wave source anomalies in the extratropical North Pacific and in the subtropical North Pacific. In addition, the axis of the Pacific storm track shifts southward with the positive PNA. Atmospheric heating anomalies associated with ENSO variability are confined primarily to the tropics. There is an anomalous heating center over the northeast Pacific, together with anomalies with the same polarity in the tropical Pacific, for the PDO variability. The in-phase combination of ENSO and PDO would in turn provide anomalous atmospheric energy transports towards North America from both the Tropical Pacific and the North Pacific, which tends to favor the occurrence of stationary wave anomalies and would lead to a PNA-like wave anomaly structure. The modeling results also confirm our analysis based on the observational record in the twentieth century.