Study on improved DPR sea ice concentration retrieval algorithm

Sea ice concentration (SIC) retrieval is critical for global climate change studies. However, in the widely applied conventional Dual-Polarization Ratio (DPR) SIC retrieval algorithm, the core parameter α is set as a fixed value (0.92), neglecting the radiometric property differences caused by various sea ice types and their spatial distributions. To overcome this limitation, this study proposed an improved DPR algorithm. The proposed algorithm determines the optimal α value for regions dominated by different sea ice types, thereby deriving SIC retrieval formulas for each partition. This achieves a critical optimization from a single global algorithm to a regionally adaptive algorithm. The results were validated against SIC data derived from high-resolution Landsat 8 image. Compared to the traditional DPR algorithm, the proposed algorithm demonstrated improved accuracy in SIC retrieval across first-year ice regions, multi-year ice regions, and first-year ice and seawater coexist regions. These improvements hold significant implications for polar climate change studies and for ensuring navigational safety.