Water quality monitoring and evaluation using remote-sensing techniques in China: A systematic review

Introduction: The application of remote-sensing techniques for water quality assessment has become increasingly popular in China. However, existing reviews are often limited to qualitative description and are quite fragmented. Outcomes: We conducted a quantitative systematic review to display current research status and identify the existing challenges and future directions. Our review revealed that the application of remote-sensing techniques in water quality research has expanded dramatically in China, but the spatial distribution is quite uneven. Second, the ground object spectrometer is the most widely applied data source. Water color indicators such as chlorophyll a and suspended solid are the most widely investigated in China. Third, semiempirical method is the most commonly used inversion method. Existing studies rarely considered the anthropogenic factors, which limited the model robustness and its application in human-dominated aquatic ecosystems. Discussion and Conclusion: We concluded that, in the past several decades, China has made notable progresses in monitoring and evaluation of water quality using the remote-sensing techniques (especially in inland lakes). We proposed that further improvements would be needed in terms of temporal and spatial coverage, indicator list, the incorporation of human-nature interactions, inversion accuracy, and model generalization.