[A-OS12] Marine ecosystems and biogeochemical cycles: theory, observation and modeling

[AOS12-12] Evaluation of retrieving chlorophyll a concentration and colored dissolved organic matter absorption from satellite ocean color remote sensing in the coastal waters of Hokkaido, Japan

*Tomonori Isada¹, Stanford B Hooker², Yukiko Taniuchi³, Koji Suzuki⁴ (1.Field Science Center for Northern Biosphere, Hokkaido University, 2.NASA Goddard Space Flight Center, 3.Japan Fisheries Research and Education Agency, 4.Faculty of Environmental Earth Science, Hokkaido University)

Keywords:Ocean color, SGLI/GCOM-C, Chlorophyll a, CDOM, coastal waters, Sentinel 2

Coastal ecosystems have an important role in biogeochemical cycles and ecological functions. However, coastal waters interacting with terrestrial ecosystems are strongly affected by heterogenic dynamics, such as river discharge, tidal currents, rainfall, and inflow of oceanic water. It is therefore essential to investigate and monitor the dynamics of coastal oceans at high spatial and temporal resolutions. Here, we evaluated the performance of deriving chlorophyll (Chl) a concentration and colored dissolved organic matter (CDOM) absorption (a_CDOM) as a function of wavelength (λ) from SGLI/GCOM-C, MODIS/Aqua, and VIIRS/S-NPP using match-up data collected in Hokkaido coastal waters. Our results show that the SGLI OC4 Chl algorithm with the 530 nm band with high spatial resolution of 250 m provided the best performance for retrieving Chl a concentrations in Hokkaido coastal waters among the satellite OC sensors tested in this study. We also showed that the end-member analysis (EMA) technique improved the estimation of a_CDOM(λ) from satellite observations. However, overall differences in remote sensing reflectance between in situ radiometric data and satellite retrievals are still large especially in the UV and blue bands, suggesting that the improvement of the atmospheric correction is a likely research area in optically complex coastal waters.