Fidelity of global tropical cyclone activity in a new reanalysis dataset (CRA40)

Abstract

This study systematically evaluated global tropical cyclone (TC) activity in a new global atmospheric reanalysis dataset named the “40-year Global Reanalysis” (CRA40) against the best track data. For comparison, four state-of-the-art reanalyses—ERA5, JRA55, CFSR, and MERRA2—were also assessed. The results showed that there is a general underestimation of global TC genesis frequency and intensity in both CRA40 and other reanalyses. A detailed investigation of spatial distribution, seasonality, interannual variation, and long-term trend for TC genesis frequency, as well as pressure–wind relationship for TC intensity, revealed similarities and differences among these reanalyses datasets. Overall, CRA40 does not exhibit clear advantages over other reanalyses in these aspects, but its biases are also not more pronounced. However, regarding TC translation speed, CRA40 outpeforms other reanalyses, evident by its high level of consistency with the observation in the zonal average pattern, meridional distribution at peak latitudes, and interannual variation, suggesting its reasonable capability in capturing large-scale atmospheric characteristics. Our findings indicate that the use of CRA40 is appropriate for conducting TC-related studies, within the scope of its limitations.