<![CDATA[The southern waters of Indonesia represent one of the active cyclogenesis regions in the Southern Hemisphere and are vulnerable to extreme marine weather events associated with tropical cyclone activity. However, the spatial characteristics of surface wind and significant wave height associated with Tropical Cyclone Errol in April 2025 have not been widely investigated. This study aims to analyze the spatial characteristics of surface wind and significant wave height during the development of Tropical Cyclone Errol and evaluate the performance of ERA5 reanalysis data in representing cyclone track and intensity as input for the SWAN model. ERA5 data were integrated into the SWAN model, while ERA5 performance was evaluated by comparing cyclone track and central pressure with Bureau of Meteorology (BoM) best-track data using correlation analysis. The results indicate that ERA5 represents the cyclone track very well (R > 0.96), while central pressure shows moderate agreement (R = 0.67). SWAN simulations show that during the maximum intensity phase, surface wind speed reached approximately 14 m/s, accompanied by significant wave heights of 1.25–3 m, compared with 0–0.5 m during the initial phase. Validation against Jason-3 altimetry yielded a correlation of 0.62, R² of 0.38, and RMSE of 0.95 m. These results demonstrate that ERA5 can adequately represent Tropical Cyclone Errol and provide suitable forcing for SWAN, although SWAN tends to underestimate higher wave conditions.]]>
