The SMOS mission currently provides multi-angular L-band (1.4 GHz) brightness temperature images of the Earth, originally designed to monitor moisture content over land and sea surface salinity over the oceans. Nevertheless, because upwelling radiation at 1.4 GHz is significantly less affected by rain and atmospheric effects than at higher microwave frequencies, the new SMOS measurements offer also a unique opportunities to complement existing satellite ocean observations at very high winds, which are often erroneous in these extreme conditions.

The objective of this project is to exploit the identified capability of SMOS L1 Brightness Temperatures to monitor wind speed and whitecap statistical properties beneath hurricanes and severe storms. Such new capability at the core of the project was recently demonstrated by analysing SMOS data over a category 4 hurricane. Without correcting for rain effects, the wind-induced components of SMOS ocean surface brightness temperatures were co-located and compared to observed and modelled surface wind speed products. The evolution of the maximum surface wind speed and the radii of 34, 50 and 64 knots surface wind speeds retrieved from SMOS were shown to be consistent with hurricane model solutions and observation analyses. During the project this feature will be extensively verified in other cases, with the aim of producing a SMOS-derived storm catalogue. The SMOS sensor is thus closer to a true all-weather ocean wind sensor with the capability to provide quantitative and complementary surface wind information of great interest for operational hurricane intensity forecasts.

As an additional application, the relevance of using SMOS salinity measurement for assessing hurricanes strength intensification and decline is also foreseen.