Peering Inside Tropical Cyclones With the WIVERN Space‐Borne Doppler Radar

Abstract The WIVERN (Wind Velocity Radar Nephoscope) mission significantly enhances the global tropical cyclone observing system. Operating from a 500 km near‐polar orbit, the 3 m diameter conically scanning antenna provides an 800 km swath. The radar operated at 94 GHz (3 mm wavelength) provides high‐resolution observations with a vertical resolution of 600 m and horizontal resolution finer than 1 km. With quasi‐daily global coverage, WIVERN measures in‐cloud tropical cyclone winds from 1 km above the surface to the upper troposphere. Simulations of the Weather Research and Forecasting model with 1.5 km grid spacing were carried out for Hurricane Milton (2024) to serve as a testbed to demonstrate the potential capabilities of the WIVERN mission and its associated data products. The high‐resolution simulation successfully reproduces the hurricane's trajectory and intensification, capturing a remarkable 78‐knot increase in maximum sustained wind speed during the 24‐hr period from 7 October to 8 October. End‐to‐end simulations demonstrate that WIVERN: (a) can provide a three‐dimensional view of the horizontal wind inside cyclones, in particular capturing the vertical wind shear, the upper level divergence and the in‐cloud circulations inside the anvil produced by the hurricane convective towers, and some of the inflow and outflows in the lower layers of the atmosphere; (b) in presence of close‐in‐time overpasses, has the potential to detect the intensification of cyclone by estimating the maximum winds in the inner core; (c) can profile the tropical cyclone ice mass as a function of the distance from the eye, which will help shed light on the anvil formation and dissipation mechanisms.