1,2,- 1National Central University, Graduate Institute of Hydrological & Oceanic Sciences, Graduate Institute of Hydrological & Oceanic Sciences, Taiwan (duongmyhoa20062000@gmail.com)
- 2Advanced Research Center for Earth Sciences, National Central University
- 3Taiwan Space Agency
Taiwan’s Triton satellite carries a GNSS-Reflectometry (GNSS-R) payload designed to investigate bistatic L-band microwave scattering over the ocean and cryosphere. In this study, we present Arctic observations acquired during multiple overpasses from the late 2025 to early 2026, focusing on both the spatial coverage of specular points (SPs) and the physical interpretation of delay–Doppler map (DDM) signatures over sea-ice-covered regions.
Accumulated SP tracks over a three-months period demonstrate that Triton’s high-inclination orbit enables systematic sampling beyond 88°N, extending into the central Arctic Basin where conventional monostatic microwave sensors and existing GNSS-R missions, such as CYGNSS, do not provide coverage. In addition, Triton offers approximately four times higher resolution in both delay and Doppler dimensions compared to CYGNSS, enhancing sensitivity to subtle variations in surface scattering regimes.
Beyond spatial coverage, first-look analyses of high-resolution DDMs collocated with passive microwave sea ice concentration products reveal distinct scattering characteristics over marginal ice zone and partial ice cover conditions. Observed DDMs exhibit energy concentrated near the specular delay with pronounced elongation in the Doppler dimension, while remaining relatively confined in delay. This behavior is consistent with quasi-specular scattering from ice floes and reduced surface roughness.
The enhanced delay resolution further provides a framework to assess the potential contribution of subsurface or multi-layer reflections at L-band, which may become detectable under thicker or more consolidated ice conditions. These results indicate that high-resolution GNSS-R observations from Triton are sensitive not only to the presence of sea ice, but also to changes in scattering mechanisms related to ice structure and surface state. Ongoing work aims to systematically classify DDM observables across ice regimes and seasons, assessing the feasibility of GNSS-R as a complementary tool for Arctic sea ice characterization.
Figure. Spatial Cover over the Arctic region from 2025/10/02 to 2026/01/08 by TRITON satellite
How to cite: Duong, H., Chien, H., Chen, M.-Y., Lin, L.-C., and Yeh, W.-H.: High-Resolution GNSS-Reflectometry Observations of Arctic Sea Ice from Taiwan’s Triton Satellite, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8600, https://doi.org/10.5194/egusphere-egu26-8600, 2026.
