A Multi‐Sensor Approach for the Characterization of Tropical Cyclone Induced Swell—Application to TC Larry, 2021

Abstract Sea states are likely highly complex and variable under tropical cyclone (TC) conditions. Outrunning the inner core TC vortex, swell systems can radiate in different directions with different wavelengths. Jointly using several sources of wave observations, it is demonstrated that directional properties of wave fields induced by a TC can now be very well recovered. Directional wave information extracted from Sentinel‐1 wave mode and CFOSAT SWIM are combined with Sofar Spotter drifters and NDBC buoy network. Specific filtering is applied to deal with respective limitations of these observation systems. High consistency between the different data sources is generally obtained, to provide evolving directional distributions of radiating swell systems during the whole TC life time. TC wave properties can then trace particular events associated to extended fetch effects, quantifying the asymmetrical directional wavelength distributions, as function of the TC main characteristics evolving with time (intensity, size, translation).