Performance of JAXA’s SGLI standard ocean color products for oceanic to coastal waters: chlorophyll a concentration and light absorption coefficients of colored dissolved organic matter

We present the performance of JAXA’s SGLI standard algorithms for estimating chlorophyll a (chl a) concentration and the
light absorption coefcients of colored dissolved organic matter (CDOM) using recently compiled high-quality data obtained
from oceanic to coastal waters. Prior to the evaluation of the algorithms, we frst compare two forward models (Gordon et al.
in J Geophys Res 93(D9):10909-10924, 1988: G88 and Park and Ruddick in Appl Opt 44(7):1236–1249, 2005: PR05) using
a wide range of inherent optical properties (IOPs) to (1) examine if the water refectance is appropriately reproduced and (2)
correct measured refectance in terms of its bidirectionality. Based on a good reproducibility of water refectance using the
PR05, the optimized IOPs are further used for explaining errors in estimates of chl a concentration and CDOM absorption
when using the SGLI, the GSM (Maritorena et al. in Appl Opt 41:2705–2714, 2002), and the QAA (Lee et al. in Appl Opt
41:5755, 2002) inversion algorithms. Results show that the mean error for estimating chl a concentration using the SGLI
algorithm is 110% for our dataset. Although this error is lower than that of the GSM and the QAA algorithms, a signifcant
underestimate at chl a higher than 2.0 mg m−3 is observed, which is further shown by independent match-up analyses.
Another SGLI CDOM product includes the mean error of 50% and shows deviation at high CDOM range (>1.0 per m). A
similar trend is observed for the GSM but not for the QAA when a global relationship of CDOM to colored detrital matter
is applied. The sources of errors are discussed for potentially improving the retrievals