Characteristics of warm cores of tropical cyclones in a 25-km-mesh regional climate simulation over CORDEX East Asia domain

In this study, the characteristics of the tropical cyclone (TC) warm cores in high resolution reanalysis dataset (ERA5) and a 25-km-mesh regional climate simulation over CORDEX East Asia domain during 1988-2009 are analyzed. The Kain-Fritsch scheme with new convection trigger function (Ma and Tan, Atmos Res 92:190-211, 2009; KFMT), the renewed Kain-Fritsch convective parameterization (Kain, J Appl Meteorol 43:170-181, 2004; KF) and the simplified Arakawa-Schubert scheme (Arakawa and Schubert, J Atmos Sci 31:674-701, 1974; SAS) are employed to illustrate the impact of cumulus parameterization schemes (CPSs) on the representation of warm core in the regional climate simulation. The TC intensity and warm core strength in ERA5 reanalysis is largely weaker than those in the regional climate simulations. In ERA5 reanalysis and three regional climate simulations, the warm core strength shows a significant positive correlation with TC intensity, but the warm core height has no correlation with TC intensity, especially during the intensifying stage of TCs. The results also show that CPS has a great impact on the warm core structures of simulated TCs. The TC warm core strength is strongest in KFMT experiment and weakest in SAS experiment, which is consistent with the differences in the TC intensities. The TC warm core heights in the KF and KFMT experiments are significantly higher than that in SAS experiment. These differences of TC warm core strength and height are mainly due to the discrepancy in the simulation of convective activities with different CPSs. The results of this study point out that the ability of climate model to simulate TC intensity is strongly related to the model capability to simulate the TC thermal structure, which is influenced by convection representations in the model.

Automated summary

The study analyzed the characteristics of tropical cyclone warm cores in high resolution reanalysis dataset and regional climate simulations, and found that the warm core intensity is positively correlated with TC intensity, while warm core height has no correlation with TC intensity. The parameterization schemes for cumulus convection have a significant impact on the warm core structures of simulated TCs, with different schemes leading to differences in warm core strength and height.