2014 Volume 34 Issue 4 Pages 278-285
Several ocean algorithms have been developed for the Second-Generation Global Imager (SGLI) on the Global Climate Observation Mission - Climate (GCOM-C) satellite (planned launch, 2016). Here we present verification of the ocean algorithms designed to retrieve the inherent optical properties, phytoplankton functional types and primary productivity. The satellite algorithm verification is defined here to evaluate accuracy of target variables using input parameter(s) obtained from in situ measurements rather than from satellite measurements. The verification of inherent optical properties (IOP) algorithms showed RMSE of 0.12, 0.22, and 0.05 for the absorption coefficient of phytoplankton, detrital materials plus colored dissolved organic materials, and the backscattering coefficient of suspended particles, respectively. Verification of the primary production algorithm indicated that it almost satisfied the values measured in situ by a factor of 2. Other algorithms such as phytoplankton functional types (PFTs) and size classes (PSCs) algorithms, which can be derived from the optical properties of phytoplankton rather than from chlorophyll a concentration, showed RMSE of 10.1-11.6 % in a relative abundance of PFTs/PSCs. Towards validation of the ocean algorithms, a radiometer called the Compact-Optical Profiling System (C-OPS), as well as another compact radiometer system specifically designed for turbid waters, were configured for in situ observation. The latter was found to reduce shelf-shading error to within 10 %. Furthermore, Ultra-High Performance Liquid Chromatography systems (UHPLC) have been developed for rapid measurements (7 min) of phytoplankton pigments in a water sample (conventional HPLC takes 30 min). This new system significantly increases spatio-temporal coverage of in situ data required for algorithm validation.
