Research on the Backscattering Characteristics of HY-2C Satellite Radar Altimeter Over Desert Surface

The backscatter coefficient measured by satellite radar altimeters is crucial for retrieving sea surface wind speed and correcting sea state biases in sea surface height (SSH) products, with its calibration directly determining altimetry accuracy. While tropical rainforests are preferred calibration sites for large-incidence-angle radars (e.g., microwave scatterometer), desert environments demonstrate superior performance in altimeter calibration. The backscattering characteristics of China’s HY-2 satellite altimeters over desert regions remain underexplored. This study focuses on HY-2C altimeter by conducting waveform retracking and statistical analysis over typical Chinese desert areas, addressing missing official data products over land surfaces. (e.g., surface elevation and backscatter coefficient). Results reveal that typical desert waveforms exhibit remarkable similarity to ocean counterparts, enabling successful backscatter coefficient retrieval through waveform retracking, with the fast adaptive algorithm achieving optimal performance. HY-2C’s Track 62 demonstrates excellent backscatter coefficient stability (Ku/C-band standard deviations: 0.320/0.367 dB). Collinear comparisons to Jason-3 Track 166 (spatial proximity<15 km, temporal interval<1 day) show strong backscatter coefficients’ consistency ( $R =0.83$ , SE = 0.20 dB). This work enhances HY-2C’s backscatter coefficients’ measurement capability over desert/land surfaces, providing critical insights for future altimeter calibration site selection.