Russian Journal of Earth Sciences Russian Journal of Earth Sciences Russian Journal of Earth Sciences 1681-1208 104257 10.2205/2025ES001082 wqdudv ОРИГИНАЛЬНЫЕ СТАТЬИ ORIGINAL ARTICLES ОРИГИНАЛЬНЫЕ СТАТЬИ Reconstruction of the Angular Dependence of the Sea Ice Backscattering Pattern According to the GNSS-R Data Reconstruction of the Angular Dependence of the Sea Ice Backscattering Pattern According to the GNSS-R Data https://orcid.org/0000-0002-9535-4949 Ковалдов Дмитрий Алексеевич Kovaldov Dmitriy Alekseevich 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 Институт прикладной физики РАН Россия Institute of Applied Physics, Russian Academy of Sciences Russian Federation Федеральный исследовательский центр Институт прикладной физики Российской академии наук Nizhny Novgorod RU Institute of Applied Physics Nizhny Novgorod RU 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 01 12 2025 01 12 2025 25 5 ES5022 16 09 2025 06 11 2025 https://rjes.ru/en/nauka/article/104257/view

This study addresses the challenge of understanding sea ice microwave scattering properties by developing a novel method to retrieve scattering indicatrix and angular dependence of backscattering patterns from Global Navigation Satellite System Reflectometry (GNSS-R) data. Sea ice remote sensing in quasi-specular reflection area requires theoretical models validated using experimental data across different frequency bands. However, only limited observations of quasispecular scattering in the L-band exist. We developed an algorithm to convert Doppler spectra from delay-Doppler maps (DDM) obtained by the TDS-1 satellite into scattering indicatrix and then to angular dependence of the sea ice backscattering patterns, using geometric transformations from bistatic sensing geometry. The method was applied to approximately 100 DDM measurements over the Sea of Okhotsk during February–March 2017, where ice concentration remained at 90–100% with temperatures below 0 °C. Results show that L-band (19 cm wavelength) exhibits broader angular dependence compared to Ka-band (8.45 mm) and Ku-band (2.21 cm) measurements from dual-frequency precipitation radar (DPR), contrary to expectations based solely on surface roughness. This anomalous broadening is attributed to volume scattering effects within sea ice, where L-band signals penetrate up to one meter depth compared to millimeter-scale penetration in Ka- and Kufrequency bands. The findings provide new insights into L-band scattering mechanisms and offer a validated approach for improving theoretical models of sea ice microwave interaction.

This study addresses the challenge of understanding sea ice microwave scattering properties by developing a novel method to retrieve scattering indicatrix and angular dependence of backscattering patterns from Global Navigation Satellite System Reflectometry (GNSS-R) data. Sea ice remote sensing in quasi-specular reflection area requires theoretical models validated using experimental data across different frequency bands. However, only limited observations of quasispecular scattering in the L-band exist. We developed an algorithm to convert Doppler spectra from delay-Doppler maps (DDM) obtained by the TDS-1 satellite into scattering indicatrix and then to angular dependence of the sea ice backscattering patterns, using geometric transformations from bistatic sensing geometry. The method was applied to approximately 100 DDM measurements over the Sea of Okhotsk during February–March 2017, where ice concentration remained at 90–100% with temperatures below 0 °C. Results show that L-band (19 cm wavelength) exhibits broader angular dependence compared to Ka-band (8.45 mm) and Ku-band (2.21 cm) measurements from dual-frequency precipitation radar (DPR), contrary to expectations based solely on surface roughness. This anomalous broadening is attributed to volume scattering effects within sea ice, where L-band signals penetrate up to one meter depth compared to millimeter-scale penetration in Ka- and Kufrequency bands. The findings provide new insights into L-band scattering mechanisms and offer a validated approach for improving theoretical models of sea ice microwave interaction.

 bistatic scattering indicatrix angular dependence of backscattering sea ice remote sensing L-band GPS TDS-1 GNSS-R bistatic scattering indicatrix angular dependence of backscattering sea ice remote sensing L-band GPS TDS-1 GNSS-R The research was supported by Russian Science Foundation (RSF) project No. 23-67-10007, https://rscf.ru/project/23-67-10007/. The authors express their gratitude to A. Maksimov and R. Volgotov from the “Planeta” Research Center for preparing the data for analysis. The research was supported by Russian Science Foundation (RSF) project No. 23-67-10007, https://rscf.ru/project/23-67-10007/. The authors express their gratitude to A. Maksimov and R. Volgotov from the “Planeta” Research Center for preparing the data for analysis.

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