X- and Ku-Band SAR Backscattering Signatures of Snow-Covered Lake Ice and Sea Ice

• Published in: Remote Sensing
• Main Authors: Veijola, Katriina, Cohen, Juval, Mäkynen, Marko, Lemmetyinen, Juha, Praks, Jaan, Cheng, Bin
• Other Authors: Department of Electronics and Nanoengineering, Jaan Praks Group, Finnish Meteorological Institute, Aalto-yliopisto, Aalto University
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2024
• Subjects: remote sensing; sea ice; snow; synthetic aperture radar; Northern Finland; Sea ice
• Online Access: https://aaltodoc.aalto.fi/handle/123456789/126684; https://doi.org/10.3390/rs16020369

Funding Information: This research was partly funded by ESA SnowSAR Campaign Data Analysis Study (SCADAS); ESA Contract No. 4000118400/16/NL/FF/gp. Publisher Copyright: © 2024 by the authors. In this work, backscattering signatures of snow-covered lake ice and sea ice from X- and Ku-band synthetic aperture radar (SAR) data are investigated. The SAR data were acquired with the ESA airborne SnowSAR sensor in winter 2012 over Lake Orajärvi in northern Finland and over landfast ice in the Bay of Bothnia of the Baltic Sea. Co-incident with the SnowSAR acquisitions, in situ snow and ice data were measured. In addition, time series of TerraSAR-X images and ice mass balance buoy data were acquired for Lake Orajärvi in 2011–2012. The main objective of our study was to investigate relationships between SAR backscattering signatures and snow depth over lake and sea ice, with the ultimate objective of assessing the feasibility of retrieval of snow characteristics using X- and Ku-band dual-polarization (VV and VH) SAR over freshwater or sea ice. This study constitutes the first comprehensive survey of snow backscattering signatures at these two combined frequencies over both lake and sea ice. For lake ice, we show that X-band VH-polarized backscattering coefficient ((Formula presented.)) and the Ku-band VV/VH-ratio exhibited the highest sensitivity to the snow depth. For sea ice, the highest sensitivity to the snow depth was found from the Ku-band VV-polarized (Formula presented.) and the Ku-band VV/VH-ratio. However, the observed relations were relatively weak, indicating that at least for the prevailing snow conditions, obtaining reliable estimates of snow depth over lake and sea ice would be challenging using only X- and Ku-band backscattering information. Peer reviewed