10:15 AM - 10:30 AM
[ACG52-06] Effect of optical properties variability on retrieval of chlorophyll a from ocean color data in Oyashio and coastal Oyashio waters in early spring
Keywords:optical property, ocean color remote sensing, Oyashio
In the coastal stations of study area where was highly turbid for a few days due to passing of a low pressure during 10–13 March, absorption coefficient of non-algal particles (ad) accounted for >60% of that of particulate matters (ap) and bbp was also higher than those in offshore stations. These optical properties induced high Rrs and resulted in overestimation of chl.a concentration by 2-3 folds when the standard ocean color chl.a algorithm was applied to the Rrs. On March 20, however, ratio of ad and bbp decreased and estimated chl.a concentration using the algorithm coincided with in situ data.
Phytoplankton absorption coefficient at 443 nm (aph(443)) and bbp(555) were linearly correlated with chl.a concentration and ad(443), respectively. Estimated values of chl.a concentration and aCDOM(443) applying these relationship to satellite ocean color data indicated that relatively higher ocean color chl.a in offshore region had interferences by non-algal particles and CDOM advected from coastal region. In this study region, satellite chl.a images should be carefully used and retrieval of chl.a from aph is better than using standard band-ratio algorithm because spatio-temporal variability in optical properties are dynamic and complicated not only in coastal region but also in offshore.