Sea surface temperature east of Australia: A predictor of tropical cyclone frequency over the western North Pacific?

The relationship between sea surface temperature (SST) east of Australia and tropical cyclone frequency over the western North Pacific (WNPTCF) is analyzed by use of observation data. The WNPTCF from June to October is correlated negatively to spring SST east of Australia. When the spring SST is in the positive phase, a cyclonic circulation anomaly in the upper troposphere and an anticyclonic circulation anomaly in the lower troposphere prevail over the western North Pacific from June to October, concurrent with an anomalous atmospheric subsidence and an enlarged vertical zonal wind shear. These conditions are unfavorable for tropical cyclone genesis, and thus WNPTCF decreases. The negative phase of the spring SST east of Australia leads to more tropical cyclones over the western North Pacific. The spring SST east of Australia may give rise to simultaneous change in tropical atmospheric circulation via the teleconnection wave train, and then subsequently affect atmospheric circulation variation over the western North Pacific.