Impact of Convection Scheme on Tropical Cyclone Frequency over the Western North Pacific in a Coupled GCM

In this study, we introduced a new convection scheme in an atmosphere–ocean-coupled model called Coupled general circulation model For the Earth Simulator (CFES). A 150-year CFES simulation shows that the SST bias is almost comparable to that of the simulation with the previous (Emanuel) convection scheme in CFES. The new convection scheme clearly improved the representation of tropical cyclone (TC) frequency over the western North Pacific (WNP) in terms of both climatology and interannual co-variability with El Niño-Southern Oscillation (ENSO). The TC-ENSO relationship is seasonally different between JJA and SON. The clear difference in ENSO-related precursor for TC variability over WNP between JJA and SON is simulated in CFES with the new convection scheme. From the lagged correlation, the new convection scheme CFES simulation reproduces tropical tropospheric cooling (warming) and its impact on the TC variability after La Niña (El Niño) (i.e., the Indian Ocean capacitor effect) in JJA and the Matsuno-Gill like pattern during El Niño in SON.