Forecasting Remote Atmospheric Responses to Decadal Kuroshio Stability Transitions
Forecasting Remote Atmospheric Responses to Decadal Kuroshio Stability Transitions
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DOI：
10.1175/jcli-d-20-0139.1
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发表时间：
2021
影响因子：
4.9
通讯作者：
L. Siqueira;B. Kirtman;L. Laurindo
中科院分区：
文献类型：
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作者：
L. Siqueira;B. Kirtman;L. Laurindo
基于观测估计和全球海洋涡分辨耦合回顾性初始化预测，我们表明，黑潮延伸变率影响降雨变率沿着北美西海岸。我们表明，当前波动和下游降雨之间的遥相关可以改善加州降水的季节性预测，我们证明，捕获这些遥相关需要具有足够海洋分辨率的耦合系统（即，涡流分解），尤其是在超过一个季节的时间尺度上。改进的预报技巧诊断方面的35年的回顾性初始集合预报与海洋涡旋解决和海洋涡旋参数化耦合模式。不仅海洋涡分辨模型表现出对黑潮延伸区在北美西部降水方面的变化的敏感性，而且海洋涡分辨预报与海洋涡参数化模型相比也表现出改进的预报技巧。海洋涡旋参数化耦合模式对黑潮延伸体的变化不敏感。我们还发现了近十年的变化与一个低对流层高度偶极子在北太平洋周围的进展，以及这些高度异常如何导致风驱动的Rossby波，影响黑潮延伸区的涡动活动的时间滞后的顺序为四年。这种十年尺度的变化（~10年）打开了北美西部降雨的多年可预测性的可能性。
Based on observational estimates and global ocean eddy-resolving coupled retrospective initialized predictions, we show that Kuroshio Extension variability affects rainfall variability along the west coast of North America. We show that the teleconnection between the current undulations and downstream rainfall can lead to improved subseasonal to seasonal predictions of precipitation over California, and we demonstrate that capturing these teleconnections requires coupled systems with sufficient ocean resolution (i.e., eddy-resolving), especially over time scales longer than one season. The improved forecast skill is diagnosed in terms of 35 years of retrospective initialized ensemble forecasts with an ocean eddy-resolving and an ocean eddy-parameterized coupled model. Not only does the ocean eddy-resolving model show sensitivity to Kuroshio Extension variability in terms of western North America precipitation, but the ocean eddy-resolving forecasts also show improved forecast skill compared to the ocean eddy-parameterized model. The ocean eddy-parameterized coupled model shows no sensitivity to Kuroshio Extension variability. We also find near-decadal variability associated with a progression of a lower-tropospheric height dipole around the North Pacific and how these height anomalies lead to wind-driven Rossby waves that affect the eddy activity in the Kuroshio Extension with a time lag on the order of four years. This decadal-scale variability (~10 years) opens the possibility of multiyear predictability of western North American rainfall.