Russian Journal of Earth Sciences Russian Journal of Earth Sciences Russian Journal of Earth Sciences 1681-1208 115679 10.2205/2026es001133 dtfeft ОРИГИНАЛЬНЫЕ СТАТЬИ ORIGINAL ARTICLES ОРИГИНАЛЬНЫЕ СТАТЬИ Investigation of L-Band Radar Signal Scattering From Ice Cover Using GNSS-R Data Investigation of L-Band Radar Signal Scattering From Ice Cover Using GNSS-R Data https://orcid.org/0000-0002-9535-4949 Ковалдов Дмитрий Алексеевич Kovaldov Dmitry Alexeevich d.kovaldov@ipfran.ru https://orcid.org/0000-0002-4054-4905 Караев Владимир Юрьевич Karaev Vladimir Yur'evich volody@ipfran.ru https://orcid.org/0000-0001-7762-7731 Титченко Юрий Андреевич Titchenko Yuriy Andreevich yuriy@ipfran.ru

кандидат физико-математических наук;

candidate of physical and mathematical sciences;

 https://orcid.org/0000-0001-7902-0212 Фатеев Вячеслав Fateev Vyacheslav https://orcid.org/0000-0001-7591-8877 Лопатин Владислав Lopatin Vladislav https://orcid.org/0000-0002-6888-280X Фейсон Хуан Huang Feixiong https://orcid.org/0000-0001-7789-0548 Ван Сяоли Wang Xiaoli https://orcid.org/0000-0001-8767-8874 Го Дзе Guo Jie Федеральный исследовательский центр Институт прикладной физики Российской академии наук Nizhny Novgorod RU Institute of Applied Physics Nizhny Novgorod RU Федеральный исследовательский центр Институт прикладной физики им. А.В. Гапонова-Грехова Российской академии наук Россия Federal Research Center A.V. Gaponov-Grekhov Institute of Applied Physics of the Russian Academy of Sciences Russian Federation ФГУП «ВНИИФТРИ» Россия FSUE «VNIIFTRI» Russian Federation ФГУП «ВНИИФТРИ» Россия FSUE «VNIIFTRI» Russian Federation Национальный центр космических наук Китайской академии наук Россия National Space Science Center, Chinese Academy of Sciences Russian Federation Институт исследований прибрежной зоны Яньтая Китайская Народная Республика Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences China Институт исследований прибрежной зоны Яньтая Китайская Народная Республика Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences China 27 04 2026 27 04 2026 26 1 ES1020 25 02 2026 21 04 2026 https://rjes.ru/en/nauka/article/115679/view

Freshwater ice cover on inland water bodies is a sensitive indicator of climate change, and its monitoring is hampered by the decline of in situ observation networks since the 1980s. Previous applications of GNSS-Reflectometry (GNSS-R) have focused mainly on sea ice detection, while its capability for seasonal freshwater ice monitoring has remained insufficiently explored. The aim of this study is to assess the sensitivity of spaceborne L-band bistatic measurements to the processes of freshwater ice cover formation, growth, and break-up on large inland lakes, and to compare the scattering behavior with that of sea ice. A full annual cycle (September 2023 – August 2024) was analyzed using data from the GNOS-II instrument onboard the Feng-Yun 3E (FY-3E) satellite at two test sites: Great Slave Lake (Canada) for freshwater ice and the Sea of Okhotsk for sea ice. Statistical moments of the Doppler spectrum – width and kurtosis coefficient – were computed from delay-Doppler maps. The results were validated against meteorological records from the Yellowknife station, MODIS imagery, and ERA5 ice thickness reanalysis. A monotonic decrease in Doppler spectrum width with decreasing air temperature was established for freshwater ice, consistent with a reduction of effective surface roughness. For freshwater ice, peak power and kurtosis coefficient show a distinct dependence on ice thickness, reflecting signal attenuation within the ice volume and dominant reflection at the ice-water interface; for sea ice these parameters remain stable, since reflection occurs at the air-ice boundary owing to high brine salinity. The findings demonstrate that L-band bistatic reflectometry provides an effective all-weather tool for operational monitoring of freshwater and sea ice, including detection of freeze-up and break-up phases, ice thickness estimation, and support for Arctic navigation.

Freshwater ice cover on inland water bodies is a sensitive indicator of climate change, and its monitoring is hampered by the decline of in situ observation networks since the 1980s. Previous applications of GNSS-Reflectometry (GNSS-R) have focused mainly on sea ice detection, while its capability for seasonal freshwater ice monitoring has remained insufficiently explored. The aim of this study is to assess the sensitivity of spaceborne L-band bistatic measurements to the processes of freshwater ice cover formation, growth, and break-up on large inland lakes, and to compare the scattering behavior with that of sea ice. A full annual cycle (September 2023 – August 2024) was analyzed using data from the GNOS-II instrument onboard the Feng-Yun 3E (FY-3E) satellite at two test sites: Great Slave Lake (Canada) for freshwater ice and the Sea of Okhotsk for sea ice. Statistical moments of the Doppler spectrum – width and kurtosis coefficient – were computed from delay-Doppler maps. The results were validated against meteorological records from the Yellowknife station, MODIS imagery, and ERA5 ice thickness reanalysis. A monotonic decrease in Doppler spectrum width with decreasing air temperature was established for freshwater ice, consistent with a reduction of effective surface roughness. For freshwater ice, peak power and kurtosis coefficient show a distinct dependence on ice thickness, reflecting signal attenuation within the ice volume and dominant reflection at the ice-water interface; for sea ice these parameters remain stable, since reflection occurs at the air-ice boundary owing to high brine salinity. The findings demonstrate that L-band bistatic reflectometry provides an effective all-weather tool for operational monitoring of freshwater and sea ice, including detection of freeze-up and break-up phases, ice thickness estimation, and support for Arctic navigation.

 Bistatic scheme Doppler spectrum delay-Doppler map freshwater ice sea ice Great Slave Lake Sea of Okhotsk FY-3E satellite kurtosis coefficient ice thickness Bistatic scheme Doppler spectrum delay-Doppler map freshwater ice sea ice Great Slave Lake Sea of Okhotsk FY-3E satellite kurtosis coefficient ice thickness The study was supported by the Russian Science Foundation (grant No. 23-77-10064), https://rscf.ru/en/project/23-77-10064/. The study was supported by the Russian Science Foundation (grant No. 23-77-10064), https://rscf.ru/en/project/23-77-10064/.

Brown L. C. and Duguay C. R. The response and role of ice cover in lake-climate interactions // Progress in Physical Geography: Earth and Environment. — 2010. — Vol. 34, no. 5. — P. 671–704. — https://doi.org/10.1177/0309133310375653 Brown L. C. and Duguay C. R. The response and role of ice cover in lake-climate interactions // Progress in Physical Geography: Earth and Environment. — 2010. — Vol. 34, no. 5. — P. 671–704. — https://doi.org/10.1177/0309133310375653 Duguay C. R., Bernier M., Gauthier Y., et al. Remote sensing of lake and river ice // Remote Sensing of the Cryosphere. — Chichester (UK) : Wiley, 2014. — P. 273–306. — https://doi.org/10.1002/9781118368909.ch12 Duguay C. R., Bernier M., Gauthier Y., et al. Remote sensing of lake and river ice // Remote Sensing of the Cryosphere. — Chichester (UK) : Wiley, 2014. — P. 273–306. — https://doi.org/10.1002/9781118368909.ch12 Duguay C. R. and Lafleur P. M. Determining depth and ice thickness of shallow sub-Arctic lakes using space-borne optical and SAR data // International Journal of Remote Sensing. — 2003. — Vol. 24, no. 3. — P. 475–489. — https://doi.org/10.1080/01431160304992 Duguay C. R. and Lafleur P. M. Determining depth and ice thickness of shallow sub-Arctic lakes using space-borne optical and SAR data // International Journal of Remote Sensing. — 2003. — Vol. 24, no. 3. — P. 475–489. — https://doi.org/10.1080/01431160304992 Duguay C. R., Pultz T. J., Lafleur P. M., et al. RADARSAT backscatter characteristics of ice growing on shallow subArctic lakes, Churchill, Manitoba, Canada // Hydrological Processes. — 2002. — Vol. 16, no. 8. — P. 1631–1644. — https://doi.org/10.1002/hyp.1026 Duguay C. R., Pultz T. J., Lafleur P. M., et al. RADARSAT backscatter characteristics of ice growing on shallow subArctic lakes, Churchill, Manitoba, Canada // Hydrological Processes. — 2002. — Vol. 16, no. 8. — P. 1631–1644. — https://doi.org/10.1002/hyp.1026 Gherboudj I., Bernier M. and Leconte R. A Backscatter Modeling for River Ice: Analysis and Numerical Results // IEEE Transactions on Geoscience and Remote Sensing. — 2010. — Vol. 48, no. 4. — P. 1788–1798. — https://doi.org/10.1109/tgrs.2009.2034256 Gherboudj I., Bernier M. and Leconte R. A Backscatter Modeling for River Ice: Analysis and Numerical Results // IEEE Transactions on Geoscience and Remote Sensing. — 2010. — Vol. 48, no. 4. — P. 1788–1798. — https://doi.org/10.1109/tgrs.2009.2034256 Hall D. K., Fagre D. B., Klasner F., et al. Analysis of ERS 1 synthetic aperture radar data of frozen lakes in northern Montana and implications for climate studies // Journal of Geophysical Research: Oceans. — 1994. — Vol. 99, no. C11. — P. 22473–22482. — https://doi.org/10.1029/94jc01391 Hall D. K., Fagre D. B., Klasner F., et al. Analysis of ERS 1 synthetic aperture radar data of frozen lakes in northern Montana and implications for climate studies // Journal of Geophysical Research: Oceans. — 1994. — Vol. 99, no. C11. — P. 22473–22482. — https://doi.org/10.1029/94jc01391 Hall D. K., Riggs G. A., Salomonson V. V., et al. MODIS snow-cover products // Remote Sensing of Environment. — 2002. — Vol. 83, no. 1/2. — P. 181–194. — https://doi.org/10.1016/s0034-4257(02)00095-0 Hall D. K., Riggs G. A., Salomonson V. V., et al. MODIS snow-cover products // Remote Sensing of Environment. — 2002. — Vol. 83, no. 1/2. — P. 181–194. — https://doi.org/10.1016/s0034-4257(02)00095-0 Howell S. E. L., Brown L. C., Kang K.-K., et al. Variability in ice phenology on Great Bear Lake and Great Slave Lake, Northwest Territories, Canada, from SeaWinds/QuikSCAT: 2000-2006 // Remote Sensing of Environment. — 2009. — Vol. 113, no. 4. — P. 816–834. — https://doi.org/10.1016/j.rse.2008.12.007 Howell S. E. L., Brown L. C., Kang K.-K., et al. Variability in ice phenology on Great Bear Lake and Great Slave Lake, Northwest Territories, Canada, from SeaWinds/QuikSCAT: 2000-2006 // Remote Sensing of Environment. — 2009. — Vol. 113, no. 4. — P. 816–834. — https://doi.org/10.1016/j.rse.2008.12.007 Huang F., Xia J., Yin C., et al. Assessment of FY-3E GNOS-II GNSS-R Global Wind Product // IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. — 2022. — Vol. 15. — P. 7899–7912. — https://doi.org/10.1109/jstars.2022.3205331 Huang F., Xia J., Yin C., et al. Assessment of FY-3E GNOS-II GNSS-R Global Wind Product // IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. — 2022. — Vol. 15. — P. 7899–7912. — https://doi.org/10.1109/jstars.2022.3205331 Jeffries M. O., Morris K., Weeks W. F., et al. Structural and stratigraphie features and ERS 1 synthetic aperture radar backscatter characteristics of ice growing on shallow lakes in NW Alaska, winter 1991-1992 // Journal of Geophysical Research: Oceans. — 1994. — Vol. 99, no. C11. — P. 22459–22471. — https://doi.org/10.1029/94jc01479 Jeffries M. O., Morris K., Weeks W. F., et al. Structural and stratigraphie features and ERS 1 synthetic aperture radar backscatter characteristics of ice growing on shallow lakes in NW Alaska, winter 1991-1992 // Journal of Geophysical Research: Oceans. — 1994. — Vol. 99, no. C11. — P. 22459–22471. — https://doi.org/10.1029/94jc01479 Kang K.-K., Duguay C. R., Howell S. E. L., et al. Sensitivity of AMSR-E Brightness Temperatures to the Seasonal Evolution of Lake Ice Thickness // IEEE Geoscience and Remote Sensing Letters. — 2010. — Vol. 7, no. 4. — P. 751–755. — https://doi.org/10.1109/lgrs.2010.2044742 Kang K.-K., Duguay C. R., Howell S. E. L., et al. Sensitivity of AMSR-E Brightness Temperatures to the Seasonal Evolution of Lake Ice Thickness // IEEE Geoscience and Remote Sensing Letters. — 2010. — Vol. 7, no. 4. — P. 751–755. — https://doi.org/10.1109/lgrs.2010.2044742 Kang K.-K., Duguay C. R., Lemmetyinen J., et al. Estimation of ice thickness on large northern lakes from AMSR-E brightness temperature measurements // Remote Sensing of Environment. — 2014. — Vol. 150. — P. 1–19. — https://doi.org/10.1016/j.rse.2014.04.016 Kang K.-K., Duguay C. R., Lemmetyinen J., et al. Estimation of ice thickness on large northern lakes from AMSR-E brightness temperature measurements // Remote Sensing of Environment. — 2014. — Vol. 150. — P. 1–19. — https://doi.org/10.1016/j.rse.2014.04.016 Karaev V., Titchenko Y., Panfilova M., et al. On the Problem of the Sea Ice Detection by Orbital Microwave Doppler Radar at the Nadir Sounding // Remote Sensing. — 2022. — Vol. 14, no. 19. — P. 4937. — https://doi.org/10.3390/rs14194937 Karaev V., Titchenko Y., Panfilova M., et al. On the Problem of the Sea Ice Detection by Orbital Microwave Doppler Radar at the Nadir Sounding // Remote Sensing. — 2022. — Vol. 14, no. 19. — P. 4937. — https://doi.org/10.3390/rs14194937 Karaev V. Yu., Panfilova M. A., Titchenko Yu. A., et al. Monitoring of Inland Waters by Dual-Frequency Precipitation Radar: First Results // IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. — 2018. — Vol. 11, no. 11. — P. 4364–4372. — https://doi.org/10.1109/jstars.2018.2874697 Karaev V. Yu., Panfilova M. A., Titchenko Yu. A., et al. Monitoring of Inland Waters by Dual-Frequency Precipitation Radar: First Results // IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. — 2018. — Vol. 11, no. 11. — P. 4364–4372. — https://doi.org/10.1109/jstars.2018.2874697 Karaev V. Yu., Sorokin E. S., Panfilova M. A., et al. On the Problem of Radar Monitoring of Ice Cover Formation and Destruction on Inland Waters: First Assessments // Russian Journal of Earth Sciences. — 2025. — Vol. 25. — ES3009. — https://doi.org/10.2205/2025es001020 — (In Russian). Karaev V. Yu., Sorokin E. S., Panfilova M. A., et al. On the Problem of Radar Monitoring of Ice Cover Formation and Destruction on Inland Waters: First Assessments // Russian Journal of Earth Sciences. — 2025. — Vol. 25. — ES3009. — https://doi.org/10.2205/2025es001020 — (In Russian). Kouraev A. V., Semovski S. V., Shimaraev M. N., et al. Observations of Lake Baikal ice from satellite altimetry and radiometry // Remote Sensing of Environment. — 2007. — Vol. 108, no. 3. — P. 240–253. — https://doi.org/10.1016/j.rse.2006.11.010 Kouraev A. V., Semovski S. V., Shimaraev M. N., et al. Observations of Lake Baikal ice from satellite altimetry and radiometry // Remote Sensing of Environment. — 2007. — Vol. 108, no. 3. — P. 240–253. — https://doi.org/10.1016/j.rse.2006.11.010 Kovaldov D. A., Karaev V. Y., Titchenko Y. A., et al. Reconstruction of the Angular Dependence of the Sea Ice Backscattering Pattern According to the GNSS-R Data // Russian Journal of Earth Sciences. — 2025. — No. 5. — ES5022. — https://doi.org/10.2205/2025es001082 Kovaldov D. A., Karaev V. Y., Titchenko Y. A., et al. Reconstruction of the Angular Dependence of the Sea Ice Backscattering Pattern According to the GNSS-R Data // Russian Journal of Earth Sciences. — 2025. — No. 5. — ES5022. — https://doi.org/10.2205/2025es001082 Kropáček J., Maussion F., Chen F., et al. Analysis of ice phenology of lakes on the Tibetan Plateau from MODIS data // The Cryosphere. — 2013. — Vol. 7, no. 1. — P. 287–301. — https://doi.org/10.5194/tc-7-287-2013 Kropáček J., Maussion F., Chen F., et al. Analysis of ice phenology of lakes on the Tibetan Plateau from MODIS data // The Cryosphere. — 2013. — Vol. 7, no. 1. — P. 287–301. — https://doi.org/10.5194/tc-7-287-2013 Latifovic Rasim and Pouliot Darren. Analysis of climate change impacts on lake ice phenology in Canada using the historical satellite data record // Remote Sensing of Environment. — 2007. — Vol. 106, no. 4. — P. 492–507. — https://doi.org/10.1016/j.rse.2006.09.015 Latifovic Rasim and Pouliot Darren. Analysis of climate change impacts on lake ice phenology in Canada using the historical satellite data record // Remote Sensing of Environment. — 2007. — Vol. 106, no. 4. — P. 492–507. — https://doi.org/10.1016/j.rse.2006.09.015 Lehner B. and Doll P. Development and validation of a global database of lakes, reservoirs and wetlands // Journal of Hydrology. — 2004. — Vol. 296, no. 1–4. — P. 1–22. — https://doi.org/10.1016/j.jhydrol.2004.03.028 Lehner B. and Doll P. Development and validation of a global database of lakes, reservoirs and wetlands // Journal of Hydrology. — 2004. — Vol. 296, no. 1–4. — P. 1–22. — https://doi.org/10.1016/j.jhydrol.2004.03.028 Leigh S., Wang Z. and Clausi D. A. Automated Ice-Water Classification Using Dual Polarization SAR Satellite Imagery // IEEE Transactions on Geoscience and Remote Sensing. — 2014. — Vol. 52, no. 9. — P. 5529–5539. — https://doi.org/10.1109/tgrs.2013.2290231 Leigh S., Wang Z. and Clausi D. A. Automated Ice-Water Classification Using Dual Polarization SAR Satellite Imagery // IEEE Transactions on Geoscience and Remote Sensing. — 2014. — Vol. 52, no. 9. — P. 5529–5539. — https://doi.org/10.1109/tgrs.2013.2290231 Long Z., Perrie W., Gyakum J., et al. Northern Lake Impacts on Local Seasonal Climate // Journal of Hydrometeorology. — 2007. — Vol. 8, no. 4. — P. 881–896. — https://doi.org/10.1175/jhm591.1 Long Z., Perrie W., Gyakum J., et al. Northern Lake Impacts on Local Seasonal Climate // Journal of Hydrometeorology. — 2007. — Vol. 8, no. 4. — P. 881–896. — https://doi.org/10.1175/jhm591.1 Lopatin V. P., Murzabekov M. M. and Bobrov D. S. Results of determining the geoid height profile and vertical line deviation using GNSS signals reflected from water surface // Geodesy and Cartography. — 2024. — Vol. 1004, no. 2. — P. 21–30. — https://doi.org/10.22389/0016-7126-2024-1004-2-21-30 — (In Russian) Lopatin V. P., Murzabekov M. M. and Bobrov D. S. Results of determining the geoid height profile and vertical line deviation using GNSS signals reflected from water surface // Geodesy and Cartography. — 2024. — Vol. 1004, no. 2. — P. 21–30. — https://doi.org/10.22389/0016-7126-2024-1004-2-21-30 — (In Russian) Mätzler C. Microwave Properties of Ice and Snow // Solar System Ices. — Dordrecht : Springer Netherlands, 1998. — P. 241–257. — https://doi.org/10.1007/978-94-011-5252-5_10 Mätzler C. Microwave Properties of Ice and Snow // Solar System Ices. — Dordrecht : Springer Netherlands, 1998. — P. 241–257. — https://doi.org/10.1007/978-94-011-5252-5_10 Mätzler C. and Wegmüller U. Dielectric properties of freshwater ice at microwave frequencies // Journal of Physics D: Applied Physics. — 1987. — Vol. 20, no. 12. — P. 1623–1630. — https://doi.org/10.1088/0022-3727/20/12/013 Mätzler C. and Wegmüller U. Dielectric properties of freshwater ice at microwave frequencies // Journal of Physics D: Applied Physics. — 1987. — Vol. 20, no. 12. — P. 1623–1630. — https://doi.org/10.1088/0022-3727/20/12/013 Mermoz S., Allain-Bailhache S., Bernier M., et al. Retrieval of River Ice Thickness From C-Band PolSAR Data // IEEE Transactions on Geoscience and Remote Sensing. — 2014. — Vol. 52, no. 6. — P. 3052–3062. — https://doi.org/10.1109/tgrs.2013.2269014 Mermoz S., Allain-Bailhache S., Bernier M., et al. Retrieval of River Ice Thickness From C-Band PolSAR Data // IEEE Transactions on Geoscience and Remote Sensing. — 2014. — Vol. 52, no. 6. — P. 3052–3062. — https://doi.org/10.1109/tgrs.2013.2269014 Panfilova M. and Karaev V. Sea Ice Detection by an Unsupervised Method Using Ku- and Ka-Band Radar Data at Low Incidence Angles: First Results // Remote Sensing. — 2023. — Vol. 15, no. 14. — P. 3530. — https://doi.org/10.3390/rs15143530 Panfilova M. and Karaev V. Sea Ice Detection by an Unsupervised Method Using Ku- and Ka-Band Radar Data at Low Incidence Angles: First Results // Remote Sensing. — 2023. — Vol. 15, no. 14. — P. 3530. — https://doi.org/10.3390/rs15143530 Panfilova M. and Karaev V. Sea Ice Detection Method Using the Dependence of the Radar Cross-Section on the Incidence Angle // Remote Sensing. — 2024. — Vol. 16, no. 5. — P. 859. — https://doi.org/10.3390/rs16050859 Panfilova M. and Karaev V. Sea Ice Detection Method Using the Dependence of the Radar Cross-Section on the Incidence Angle // Remote Sensing. — 2024. — Vol. 16, no. 5. — P. 859. — https://doi.org/10.3390/rs16050859 Prowse T. D., Bonsal B. R., Duguay C. R., et al. River-ice break-up/freeze-up: a review of climatic drivers, historical trends and future predictions // Annals of Glaciology. — 2007. — Vol. 46. — P. 443–451. — https://doi.org/10.3189/172756407782871431 Prowse T. D., Bonsal B. R., Duguay C. R., et al. River-ice break-up/freeze-up: a review of climatic drivers, historical trends and future predictions // Annals of Glaciology. — 2007. — Vol. 46. — P. 443–451. — https://doi.org/10.3189/172756407782871431 Sharma S., Richardson D. C., Woolway R. I., et al. Loss of Ice Cover, Shifting Phenology, and More Extreme Events in Northern Hemisphere Lakes // Journal of Geophysical Research: Biogeosciences. — 2021. — Vol. 126, no. 10. — https://doi.org/10.1029/2021jg006348 Sharma S., Richardson D. C., Woolway R. I., et al. Loss of Ice Cover, Shifting Phenology, and More Extreme Events in Northern Hemisphere Lakes // Journal of Geophysical Research: Biogeosciences. — 2021. — Vol. 126, no. 10. — https://doi.org/10.1029/2021jg006348 Shokr M. and Sinha N. K. Sea Ice: Physics and Remote Sensing. — Wiley, 2015. — (Geophysical Monograph Series). — https://doi.org/10.1002/9781119028000 Shokr M. and Sinha N. K. Sea Ice: Physics and Remote Sensing. — Wiley, 2015. — (Geophysical Monograph Series). — https://doi.org/10.1002/9781119028000 Titchenko Y. A., Karaev V. Y., Panfilova M. A., et al. Numerical Simulation of Radar Signal Reflected by Sea Surface with Different Sea Ice Concentration // Russian Journal of Earth Sciences. — 2025. — No. 3. — ES3007. — https://doi.org/10.2205/2025es001017 — (In Russian). Titchenko Y. A., Karaev V. Y., Panfilova M. A., et al. Numerical Simulation of Radar Signal Reflected by Sea Surface with Different Sea Ice Concentration // Russian Journal of Earth Sciences. — 2025. — No. 3. — ES3007. — https://doi.org/10.2205/2025es001017 — (In Russian). Weber F., Nixon D. and Hurley J. Semi-automated classification of river ice types on the Peace River using RADARSAT-1 synthetic aperture radar (SAR) imagery // Canadian Journal of Civil Engineering. — 2003. — Vol. 30, no. 1. — P. 11–27. — https://doi.org/10.1139/l02-073 Weber F., Nixon D. and Hurley J. Semi-automated classification of river ice types on the Peace River using RADARSAT-1 synthetic aperture radar (SAR) imagery // Canadian Journal of Civil Engineering. — 2003. — Vol. 30, no. 1. — P. 11–27. — https://doi.org/10.1139/l02-073 Yan Q. and Huang W. Spaceborne GNSS-R Sea Ice Detection Using Delay-Doppler Maps: First Results From the U.K. TechDemoSat-1 Mission // IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. — 2016. — Vol. 9, no. 10. — P. 4795–4801. — https://doi.org/10.1109/jstars.2016.2582690 Yan Q. and Huang W. Spaceborne GNSS-R Sea Ice Detection Using Delay-Doppler Maps: First Results From the U.K. TechDemoSat-1 Mission // IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. — 2016. — Vol. 9, no. 10. — P. 4795–4801. — https://doi.org/10.1109/jstars.2016.2582690 Yan Q. and Huang W. Sea Ice Sensing From GNSS-R Data Using Convolutional Neural Networks // IEEE Geoscience and Remote Sensing Letters. — 2018. — Vol. 15, no. 10. — P. 1510–1514. — https://doi.org/10.1109/lgrs.2018.2852143 Yan Q. and Huang W. Sea Ice Sensing From GNSS-R Data Using Convolutional Neural Networks // IEEE Geoscience and Remote Sensing Letters. — 2018. — Vol. 15, no. 10. — P. 1510–1514. — https://doi.org/10.1109/lgrs.2018.2852143 Yan Q., Huang W. and Moloney C. Neural Networks Based Sea Ice Detection and Concentration Retrieval From GNSS-R Delay-Doppler Maps // IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. — 2017. — Vol. 10, no. 8. — P. 3789–3798. — https://doi.org/10.1109/jstars.2017.2689009 Yan Q., Huang W. and Moloney C. Neural Networks Based Sea Ice Detection and Concentration Retrieval From GNSS-R Delay-Doppler Maps // IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. — 2017. — Vol. 10, no. 8. — P. 3789–3798. — https://doi.org/10.1109/jstars.2017.2689009 Yang Y., Moore P., Li Z., et al. Lake Level Change From Satellite Altimetry Over Seasonally Ice-Covered Lakes in the Mackenzie River Basin // IEEE Transactions on Geoscience and Remote Sensing. — 2021. — Vol. 59, no. 10. — P. 8143–8152. — https://doi.org/10.1109/tgrs.2020.3040853 Yang Y., Moore P., Li Z., et al. Lake Level Change From Satellite Altimetry Over Seasonally Ice-Covered Lakes in the Mackenzie River Basin // IEEE Transactions on Geoscience and Remote Sensing. — 2021. — Vol. 59, no. 10. — P. 8143–8152. — https://doi.org/10.1109/tgrs.2020.3040853 Zhu Y., Yu K., Zou J., et al. Sea Ice Detection Based on Differential Delay-Doppler Maps from UK TechDemoSat-1 // Sensors. — 2017. — Vol. 17, no. 7. — P. 1614. — https://doi.org/10.3390/s17071614 Zhu Y., Yu K., Zou J., et al. Sea Ice Detection Based on Differential Delay-Doppler Maps from UK TechDemoSat-1 // Sensors. — 2017. — Vol. 17, no. 7. — P. 1614. — https://doi.org/10.3390/s17071614