Impacts of ENSO and Madden-Julian oscillation on the genesis of tropical cyclones simulated by general circulation models and compared to observations

Abstract

Using the Seoul National University Earth System Model Version 0 (SEM0) and Community Earth System Model version 1 (CESM1), we analyzed the impacts of El Niño-Southern oscillation (ENSO) and Madden-Julian oscillation (MJO) on the genesis of tropical cyclones (TG). SEM0 is known to simulate ENSO, MJO, and TG reasonably well, all of which are difficult to simulate with general circulation models (GCMs). Observational analysis revealed that both ENSO and MJO have substantial impacts on global TG and that the impact of ENSO (MJO) on regional TG varies in a complex manner depending on the phase of MJO (ENSO). Both GCMs underestimate the observed TG over the North Atlantic and have relatively poor performance for simulating the TG anomalies associated with ENSO compared to simulating those associated with MJO. Overall, SEM0 shows much better performance than CESM1 in terms of reproducing the observed impacts of MJO and combined impacts of ENSO and MJO on TG. Therefore, SEM0 can serve as a useful tool for studying the interactions among them to improve the forecasting of tropical cyclones.