Process study on decadal variations of the North Pacific oceanic fronts using initialized hindcast data

通过对初始后发资料和观测资料的分析，阐明了太平洋年代际振荡信号最强烈的北太平洋洋锋附近控制年代际变化的物理过程。在副热带锋面上，对锋面结构和海洋环流的热输运的真实表征有助于提高对海洋温度年代际变化的预测能力。另一方面，在亚北极锋上，我们的误差敏感性分析表明，海洋对阿留申低压波动的延迟响应主要通过海洋罗斯比波调整来控制我们的年代际预测的质量。在气候模拟和初始化方面，特别是在减少亚北极锋的预测不确定性方面，我们应该进一步关注这些过程在温带大气和热带大气-海洋耦合中的作用。

By analyzing initialized hindcast data together with the observations, we have clarified the physical processes controlling decadal variations around the oceanic fronts of the North Pacific, where the signals of the Pacific Decadal Oscillation are observed strongest. Over the subtropical front, realistic representation of the front structure and the heat transport by the ocean gyre circulation contributes to our high skill in predicting the decadal changes of the ocean temperature. Over the subarctic front, on the other hand, our error sensitivity analyses have revealed that the delayed response of the ocean to the Aleutian Low fluctuations controls the quality of our decadal hindcasts primarily through the oceanic Rossby wave adjustment. For the climate modelling and the initialization, particularly toward reducing prediction uncertainty over the subarctic front, we should further focus on these processes in the extratropical atmosphere and the tropical atmosphere-ocean coupling.