Impacts of Ocean-Atmosphere Interaction in the Pacific Asian Marginal Seas on the Variability of the North Pacific Oscillation/Victoria Mode

The interannual variability of North Pacific Oscillation (NPO)/Victoria Mode (VM) is found to be closely linked with the surface winds and temperature in the Pacific Asian Marginal Sea (PAMS). The coupled oceanic and atmospheric processes in the PAMS are analyzed. Composite analysis indicates an enhanced surface latent heat flux anomalies develop in response to Sea Surface Temperature (SST) in the strong NPO/VM phase. The winter SST and meridional wind anomalies in the PAMS acts as a pivotal driver to modulate the NPO/VM pattern through atmospheric teleconnection. The upper-level eastward propagation strengthens the south lobe of the NPO from the subtropical pressure low anomaly. Dynamical processes are validated using the observation and the Linear Baroclinic Model. Further analysis shows that the East Asian Winter Monsoon (EAWM) may play an important role in controlling low-level meridional wind variability in the PAMS but does not explain its completed variability. Finally, the impacts of storm-track are also evaluated.