Feasibility Demonstration of Using the Signal‐to‐Noise Ratio Observations From Geodetic GNSS Receivers to Retrieve Dry Snow Density
Abstract The geodetic Global Navigation Satellite System (GNSS) receiver has been proven to retrieve snow depth using the phase change rate of the signal‐to‐noise ratio (SNR) observations. Snow density can be related to snow permittivity and is theoretically sensitive to the amplitude of the GNSS re...
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| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2025-04-01
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| Series: | Water Resources Research |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2023WR036657 |
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| Summary: | Abstract The geodetic Global Navigation Satellite System (GNSS) receiver has been proven to retrieve snow depth using the phase change rate of the signal‐to‐noise ratio (SNR) observations. Snow density can be related to snow permittivity and is theoretically sensitive to the amplitude of the GNSS reflected signal. However, retrieving snow density using the SNR observations is challenging due to the difficulty in extracting the reflected amplitude since it hides in the interference waveform and changes with the satellite elevation angle. Overcoming this issue by taking an indirect path, this study proposes a novel GNSS Signal Amplitude Ratio Model (GSARM) that relates the corrected amplitude ratio (α) to the snow permittivity and the resulting snow density. First, the model extracts the instantaneous amplitude from SNR observations to derive an initial amplitude ratio (α0). Then, it uses a step‐wise strategy to correct systematic errors from antenna gain and random errors from soil moisture in α0 to achieve the finalized corrected α. The GSARM‐derived dry snow density is compared with three other data sources, that is, the PBO‐H2O, the ERA5‐Land, and the in situ measurements over two GNSS sites for six consecutive years. The overall mean RMSD (RMSPD) values of snow density for GSARM compared to PBO‐H2O, ERA5‐Land, and in situ measurements are 0.036 g/cm3 (22.08%), 0.040 g/cm3 (21.43%), and 0.032 g/cm3 (23.05%), respectively. The corresponding MAD (MAPD) values are 0.029 g/cm3 (21.90%), 0.035 g/cm3 (18.46%), and 0.025 g/cm3 (22.87%), respectively. The findings of this study first prove the feasibility of using geodetic GNSS receivers for snow density retrieval. It also provides supportive information for extending the added‐value applications of traditional geodetic GNSS sites and for developing new observation patterns. |
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| ISSN: | 0043-1397 1944-7973 |