Challenges in Microwave Surface Emissivity Estimation
Webinar Speaker: Catherine Prigent, Centre National de la Recherche Scientifique (CNRS) in Paris Observatory
About the Webinar
Satellite passive microwave observations are widely used to characterize the Earth atmosphere (e.g., temperature and humidity profiles, precipitation) or the Earth surface (e.g., ocean surface temperature or wind speed, soil moisture, sea ice concentration). The contribution from the Earth surface is considered as a source of noise in the first case and as the source of information in the second case, but for both applications an accurate estimation of the surface emissivity is required to exploit the signal. With an increasing use of the microwaves in the coming years for meteorological and climatological applications, from ~1 to ~700 GHz (from CIMR to ICI), robust and consistent understanding and quantification of the surface emission have to be established, including all types of environments (ocean, ice and snow, arid and vegetated surfaces).
Different methodologies have been developed to estimate the surface emissivity, from fully physical models to satellite-derived atlases, depending on the surface types, along with their associated uncertainties. A possible parameterization of the emissivity, driven by physical understanding and anchored to satellite observations, will be discussed. Different issues will be mentioned, including the foam impact over ocean at high wind speeds, the snow effect over sea ice, the sub-surface contributions in arid regions, or the diurnal variations of the emissivity in the vegetation.
About the Speaker
Catherine Prigent (Member, IEEE) received the Ph.D. degree in physics from Paris University, Paris, France, in 1988.,Since 1990, she has been a Researcher with the Centre National de la Recherche Scientifique (CNRS), Paris Observatory, Paris. From 1995 to 2000, she was on leave from the CNRS and she worked at NASA/Goddard Institute for Space Studies, Columbia University, New York, NY, USA. She is the Co-Founder of Estellus, Paris, a small company specialized in satellite Earth observations. Her research covers satellite microwave remote sensing of the Earth, for both surface and atmosphere characterization for global applications. It includes RT modeling work (e.g., microwave ocean surface emissivity), retrieval of key surface variables (e.g., microwave land surface temperature, surface water extent, and ocean ice concentration), or the development of cloud estimates from millimeter waves. She is involved in the preparation of several satellite instruments, with ESA, EUMETSAT, and CNES (e.g., MWI and ICI onboard MetOp-SG, the Copernicus CIMR mission, and SWOT).