Tropical Storm Monitoring with SMOS Sensor: An Overview of the SMOS+STORM Project
Reul, Nicolas1; Chapron, bertrand1; Tenerelli, Joseph2; Quilfen, yves1; Sabia, Roberto3; Fernandez, Diego3

The Soil Moisture and Ocean Salinity (SMOS) mission provides multi-angular L-band (1.4 GHz) brightness temperature images of the Earth. Because upwelling radiation at 1.4 GHz is significantly less affected by rain and atmospheric effects than at higher microwave frequencies, the SMOS measurements offer unique opportunities to complement existing ocean satellite high wind observations that are often erroneous in these extreme conditions.

In this talk, we shall provide an overview of the results of the SMOS+STORM STSE project which aimed to exploit the identified capability of SMOS L1 Brightness Temperatures to monitor wind speed and whitecap statistical properties beneath Tropical Cyclones and severe storms. Such new capability at the core of the project was recently demonstrated by analysing SMOS data over the category 4 hurricane IGOR that developed in September 2010. 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 has been extensively verified in other cases (such as for hurricane SANDY in 2012), 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 over waters were upper ocean density stratification is salt-driven (barrier-layers over the Amazon-Orinoco river plumes, Bay of Bengal,.. ) has also been analysed. We shall present an overview of these new capabilities