Assessment of tropical cyclones in the Bureau of Meteorology’s atmospheric high-resolution regional reanalysis for Australia

Verification of atmospheric reanalysis products is crucial for their application in extreme weather and climate-related research. This study evaluates tropical cyclone (TC) characteristics and related variables from 1990 to 2018 over Australia (95–160°E and 0–30°S) in three reanalysis products – the recently developed Australian Bureau of Meteorology’s Atmospheric high-resolution Regional Reanalysis for Australia Version 2 (BARRA-R2), its predecessor BARRA-R (both at 12-km spatial resolution) and the widely used European Centre for Medium-Range Weather Forecasts (ECMWF)’s Global Reanalysis Version 5 (ERA5) at 31-km spatial resolution. TCs detected in these reanalyses, using the Okubo–Weiss–Zeta Parameter detection and tracking scheme, are compared with observations from the Bureau’s TC database. All three products simulated more than 50% of the observed TC frequency, with ERA5 achieving a higher hit rate of 77% compared with BARRA-R2 (68%) and BARRA-R (53%). Most missed cases involved non-severe TCs. ERA5 showed a clear decline in annual TC frequency consistent with observations, whereas BARRA-R displayed a weak upward trend and BARRA-R2 a statistically insignificant decline. Large differences emerged in surface wind speed and gusts: BARRA-R represented TC surface winds better than ERA5, and BARRA-R2 produced slightly improved gusts compared with ERA-5. Case studies show that temporal evolution is generally well represented in all products, though ERA5 tends to maintain peak intensity for longer, whereas BARRA products sometimes show shifted timing of peak intensity. General discrepancies are attributed to resolution limitations, inherent differences between best-track and gridded data, underestimation of TC peak intensity and wider model forecast constraints.