Deriving Phytoplankton Characteristics from Optical Properties in the South China Sea and Sulu Sea
Bracher, Astrid¹; Taylor, Bettina²; Cheah, Wee²; Dinter, Tilman³; Steinmetz, Francois^4
1Alfred-Wegener-Institute Helmholtz Center for Polar and Marine Research, GERMANY; ²Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine Research, GERMANY; ³Institute of Environmental Physics, University of Bremen, GERMANY; ⁴HYGEOS, FRANCE

Optical properties of phytoplankton in the South China Sea and Sulu Sea were measured during the SHIVA (Stratosphere Halogens in a Varying Atmosphere) field campaign onboard Sonne in November 2011. By using a combination of techniques apparent optical properties (AOPs such as reflectances, remote sensing reflectances (RRS), attenuation coefficients), inherent optical properties (IOPs such as absorption, fluorescence) and pigment composition were determined. For the time of the cruise, total chlorophyll a concentration and RRS were calculated using the HYGEOS-POLYMER algorithm based on data obtained from MERIS. The chl-a conc. of different phytoplankton groups as monthly mean were calculated using SCIAMACHY data and applying the PhytoDOAS technique. The in-situ data were used to validate satellite data on total chl-a, phytoplankton groups chl-a and RRS. From the in-situ data region specific relationships of total biomass and phytoplankton group specific biomass to IOPs and AOPs were derived and the adapted algorithms were applied to the satellite data. With those results, recommendations for improving satellite algorithms to derive phytoplankton characteristics in the South China Sea and Sulu Sea have been developed.