The Numerical Simulation Study Of Atmospheric Response To Reemergence Of North Atlantic Ocean Variability In Gulf Stream

In this paper, we investigate impacts of anomalous oceanic temperature reemergence of Gulf Stream in the North Atlantic on general circulation of atmosphere and climate variability using a global fast ocean-atmosphere coupled model--FOAM and initial value method.FOAM successfully simulates oceanic temperature reemergence process of Gulf Stream in the North Atlantic, and the sea surface heat flux and SST anomalies are not synchronized and peak at different phase of the process. The heat flux anomaly peaks in the early winter, while SST anomaly peaks in the mid-late winter. At the results, the atmosphere responses are different in the early and mid-later winter. In the early winter, the general circulation of atmosphere anomalies are anomalous barotropic trough responses over the North Atlantic and the North Pacific respectively, and anomalous barotropic ridge responses over the Arctic region as negative phase of Arctic Oscillation (AO) forced by the surface oceanic heat flux anomaly, which cause warmer than normal in the south Europe and the north Africa and colder than normal in the Asia. In the late winter, the general circulation of atmosphere anomalies are anomalous barotropic ridge responses over the North Atlantic and the North Pacific respectively, and anomalous barotropic trough responses over the Arctic region as positive phase of AO forced by the SST anomaly, which cause colder than normal in the south Europe and the north Africa and warmer than normal in the Asia, and precipitation is 30 percent richer than normal over the eastern China. The general circulation anomalies of atmosphere over the north Pacific are propagated by stationary Rossby Wave flux from the north Atlantic, where the atmospheric anomalies are forced by the surface heat flux and SST anomalies in the Gulf Stream.Furthermore, an inter-basin teleconnection between the North Atlantic and the North Pacific ocean-atmosphere interaction has been found. In the model, an idealized oceanic temperature anomaly is initiated over the Kuroshio and the Gulf Stream extension region, respectively. The experiments explicitly demonstrate that both the North Pacific and the North Atlantic ocean-atmosphere interactions are intimately coupled through an inter-basin atmospheric teleconnection. This fast inter-basin communication can transmit oceanic variability between the North Atlantic and the North Pacific through local ocean-to-atmosphere feedbacks. The leading mode of the extratropical atmospheric internal variability plays a dominant role in shaping the hemispheric-scale response forced by oceanic variability over the North Atlantic and Pacific.