A Comparative Study on the Dynamics of the Pacific-Japan (PJ) Teleconnection Pattern Based on Reanalysis Datasets

Abstract

The Pacific-Japan (PJ) teleconnection pattern is one of the dominant summertime anomaly patterns of the atmospheric circulation that influence summertime weather conditions over the Far East. It is associated with anomalous cumulus convection over the tropical Northwestern Pacific. The present study compares the structure and energetics of the pattern based on four atmospheric reanalysis datasets currently available. PJ-associated vorticity anomalies are found similar among the four datasets, and so are its conversions of kinetic and available potential energy from the climatological-mean flow, confirming its characteristics as a dynamical mode of variability. In contrast, spatial distribution and strength of anomalous cumulus convection differ considerably among those datasets, and distribution of temperature anomalies also exhibits some discrepancies around the anomalous convection. Those discrepancies cause substantial differences in available potential energy generation due to anomalous cumulus convection, suggesting the potential that the diabatic heating can be as equally important in maintaining the PJ pattern as the dry processes.