An Optimal Strategy for Applying Combined Atmospheric Correction Approaches to Sentinel-2 MSI Over Inland and Coastal Waters

Reliable atmospheric correction (AC) is a prerequisite for quantitative water color remote sensing. However, the complex and variable optical properties of coastal and inland waters—particularly in regions with spatial intermixing of clear and turbid waters—present significant challenges to achieving stable and consistent results with existing AC algorithms. To solve this problem, this study introduces an atmospheric correction combination strategy for Sentinel-2 MSI, termed Atmospheric Correction Approach combining POLYMER and ACOLITE (ACAPO-AC) , which integrates the strengths of POLYMER in clear waters and ACOLITE-DSF in turbid waters. By constructing a logistic function based on the ratio of near-infrared to green bands, the strategy effectively captures the continuous transition between clear and turbid waters.The performance of ACAPO-AC was evaluated using a global in situ dataset. The results indicate that the ACAPO-AC achieves a coefficient of determination (R2) exceeding 0.64 for all bands, with (R2) exceeding 0.77 from 492 nm to 783 nm, and the mean relative percentage deviation (MAPD) for visible bands remaining below 50%. Compared to POLYMER and ACOLITE-DSF, the ACAPO-AC achieved slopes closest to 1 and the lowest bias and root mean square error (RMSE) across all bands (|bias|< 0.0015 sr-1,RMSE < 0.005 sr-1).Furthermore, the spatial pattern analyses of Rrs and total suspended solids (TSS) confirm that this strategy enables smooth and consistent transitions between clear and turbid waters.