Spatiotemporal Analysis of Water Quality Conditions in High-Andean Lakes Based on Satellite Indicators Using Sentinel 2 and Landsat 8/9 Images

High-Andean lakes are strategic freshwater ecosystems whose monitoring is essential for effective water resource management. However, their optical complexity limits the applicability of conventional methods. In this study, the water quality conditions of the Ozogoche lakes, located in Sangay National Park (PNS), were assessed using Sentinel-2 (S2), Landsat-8 OLI (L8), and Landsat-9 (L9) imagery processed with automated water products from the Case 2 Regional Coast Colour (C2RCC) processor, including the C2RCC, C2X-COMPLEX, and C2X versions. Comparisons between in situ chlorophyll-a (Chl-a) measurements and satellite-derived products confirmed that C2RCC achieved the lowest error (RMSE = 0.68 mg/m3). The multitemporal analysis (2016–2024) of Chl-a, total suspended solids (TSSs), and the diffuse attenuation coefficient (kd_z90max) revealed interannual variations. The results consistently classified the lakes as ultra-oligotrophic, providing an integrated perspective of their environmental quality. This study demonstrates the reliability of C2RCC products for monitoring high-Andean aquatic ecosystems and underscores the potential of remote sensing to overcome accessibility and cloud cover constraints, delivering valuable insights for the sustainable management of water resources in protected areas.