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Intercomparison of Electromagnetic Scattering Models for Delay-Doppler Maps along a CYGNSS Land Track with Topography

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posted on 11.03.2022, 04:15 by James CampbellJames Campbell, Ruzbeh Akbar, Alexandra Bringer, Davide Comite, Laura Dente, Scott Gleason, Leila Guerriero, Erik Hodges, Joel Johnson, Seungbum Kim, Amer Melebari, Nazzareno Pierdicca, Christopher Ruf, Leung Tsang, Tianlin Wang, Haokui Xu, Jiyue Zhu, Mahta Moghaddam

A comparison of three different electromagnetic scattering models for land surface delay-Doppler maps (DDMs) obtained from global navigation satellite system reflectometry (GNSS-R) along a Cyclone Global Navigation Satellite System (CYGNSS) track in the San Luis Valley, Colorado, USA, is presented. The three models are the analytical Kirchhoff solutions (AKS), the Soil And VEgetation Reflection Simulator (SAVERS), and the improved geometrical optics with topography (IGOT). Common inputs to the three models were defined by using field samples of soil moisture and texture, soil surface roughness measurements, and a digital elevation model (DEM). The resulting peak reflectivity profiles of the models and the CYGNSS data all had a dynamic range of 10 dB along the selected track, mainly due to the influence of topography. The reflectivities obtained from all three models agreed with one another to within 2.4 dB along the full length of the track. The models also showed general agreement with the corresponding CYGNSS data, although the modeled profiles were higher and smoother. Additional characterization of fine-scale surface roughness is identified as an area for future work to improve model fidelity. An intercomparison of DDM structure for three selected acquisitions is also provided.

Funding

NASA Science Mission Directorate Grant 80NSSC18K0704 with the University of Southern California

NASA Science Mission Directorate Contract NNL13AQ00C with the University of Michigan

European Space Agency Contract 4000130560/20/NL/FF/gp

History

Email Address of Submitting Author

jamesc91@usc.edu

ORCID of Submitting Author

0000-0001-6774-5275

Submitting Author's Institution

University of Southern California

Submitting Author's Country

United States of America