An inter-comparison of tropical cyclone datasets for the Australian region

Abstract Tropical cyclone (TC) best track datasets have temporal inhomogeneity, mostly associated with changes in monitoring practices and technological improvements. Temporal inconsistencies are often mitigated by using TC data from more homogeneous periods. For example, TC records since 1980 are preferred for frequency and track analysis, while records for intensity analysis have become more consistent since ∼2000. However, such measures reduce the sample size for trend analysis, potentially leading to conflicting conclusions due to natural climate-variability. Inter-agency best track data can also vary, due to differences in the way best track information—such as centre fix locations and associated intensity estimates—are defined and assessed. When comparing global datasets and regional datasets, additional inconsistencies can be introduced where TCs form or track just outside the official area of responsibility for each agency. We highlight discrepancies in Australian TC best track data from various sources by comparing it to a more rigorously scrutinized dataset compiled by the Australian Bureau of Meteorology. This dataset is found to have highly accurate TC records for the Australian region. We also highlight the implications of data differences on TC-related trend analysis, aiming to increase awareness of dataset inconsistencies while guiding credible climate-change detection and attribution messages.