H025-02
Sensitivity of Backscatter and Brightness Temperature Measurements from Satellite Radar Altimetry Missions to Lake Ice Thickness
Monday, 7 December 2020: 19:04
Virtual
Claude R Duguay, University of Waterloo, Waterloo, ON, Canada; H2O Geomatics, Waterloo, ON, Canada, Ghislain Picard, UGA,CNRS, Institut des Geosciences de l’Environnement (IGE) UMR 5001, Grenoble, France, Elena Anatolievna Zakharova, EOLA, Toulouse, France, Justin Murfitt, University of Waterloo, Geography and Environmental Management, Waterloo, ON, Canada, Marco Restano, SERCO/ESRIN, Frascati, Italy and Jérôme Benveniste, European Space Agency (ESA-ESRIN), Earth Observation Programmes, Frascati, Italy
Abstract:
Lakes that form a seasonal ice cover are a major component of the terrestrial landscape at northern high latitudes. Monitoring of ice cover extent, phenology and thickness on these lakes is critical for improving our understanding and predictive capabilities of lake-atmosphere interactions with climate warming. Lake ice thickness has been identified as an Essential Climate Variable (ECV) by the Global Climate Observing System (GCOS) given its sensitivity to changes in air temperature and on-ice snow mass (depth and density). Ground-based measurements of lake ice thickness are sparse in both space and time, and the number of sites where such measurements are made has dramatically decreased over the last two to three decades in many northern countries. In light of this and in support of GCOS, there is an urgent need to develop ice thickness products from satellite observations. Altimetry missions can play an important role in this respect, allowing for systematic measurements of ice thickness for many lakes of the globe. However, acquisition of an in-depth understanding of the interactions between microwave signals and lake ice properties is a necessary step towards the development of robust algorithms for the retrieval of ice thickness.
A new ESA-sponsored study, known under the acronym of LIAM (Lake Ice from Altimetry Missions), is examining the sensitivity of backscatter and brightness temperature measurements from ESA and non-ESA satellite radar altimetry missions to lake ice thickness of various properties. The goal of this short 12-month study is to pave the way for robust retrieval of lake ice thickness from satellite altimetry missions, supported by a thermodynamics lake ice model and the latest version of the microwave radiative transfer snow model (SMRT) which has recently been revised to include lake ice. In this presentation, we will present an overview of the study as well as early results of forward simulations of backscatter and brightness temperature using SMRT, and initial comparison of SMRT model simulations with measurements from altimetry missions for a selection of North American and European lakes.
