Retrieval of CDOM absorption coefficient with remote sensing reflectance in ultraviolet band for waters in the Changjiang (Yangtze) estuarine and coastal region

Distribution, migration and transformation of chromophoric dissolved organic matter (CDOM) in coastal waters are closely related to marine biogeochemical cycle. Ocean color remote sensing retrieval of CDOM absorption coefficient (a_g(λ)) can be used to trace the distribution and variation of runoff water from Changjiang river, and further to help understand estuarine and coastal biogeochemical processes in large spatial and temporal scales. The light absorption of CDOM and phytoplankton has distinctive yet overlapping features in the ultraviolet (UV) and visible domain. It has long been envisioned that including ocean color measurements in the UV range may help the separation of CDOM from the remotely sensed ocean color spectrum. Wei and Lee (2015) established QAA_UV by including a UV band (380nm). In this study, large amount of in situ data collected in the Changjiang estuarine and coastal waters are used to verify and calibrate QAA_UV, to improve the inversion accuracy of CDOM absorption coefficient.