Decadal Oscillation of Autumn Precipitation in Central Vietnam Modulated by the East Pacific-North Pacific (EP-NP)

Autumn precipitation over central Vietnam is associated with an increase in the occurrence of tropical cyclones that lead to frequent flooding and pose a significant threat to lives and property. The present analyses reveal a pronounced decadal oscillation of autumn precipitation in central Vietnam within the 8-11-year frequency band that is modulated by the East Pacific-North Pacific (EP-NP) teleconnection. The negative phase of the EP-NP pattern is associated with a positive sea surface temperature (SST) anomaly in the South China Sea (SCS) that induces low-level convergence, enhances convection, and increases precipitation over central Vietnam and adjacent islands including Hainan (China) and the Philippines. This circulation feature around the SCS is embedded in a large-scale circulation associated with SST anomalies across the Pacific Ocean – i.e., cooling in the eastern and central tropical Pacific sandwiched by warming in the North and South Pacific as well as the western Pacific Ocean. The positive phase of the EP-NP features opposite SST and circulation anomalies, with the result being reduced rainfall in central Vietnam. This out-of-phase relationship and shared decadal spectral coherence