| A description of depth-resolved photoproduction rates within the surface layer of natural waters requires knowledge of the coefficients of diffuse attenuation, Kd(lambda), and CDOM absorption, ag(lambda), in the UV and blue domains of natural light. For this reason, first we develop, test and validate two improved and ready-to-use algorithms for monitoring these quantities from measurements of remote sensing reflectance Rrs(lambda) measured at SeaWiFS compliant wavebands (= ocean color). A principal component analysis performed on the Rrs(lambda) data allows us to define four new orthogonal dimensions of ocean color which are used as predictors in multiple linear regressions of Kd(lambda) at 320, 340, 380, 412, 443 and 490nm.; On top of revealing the spatio-temporal variability in CO photoproduction we also provide some new insights regarding its correlation to causative underlying optical properties. Finally, we estimated that the global yearly depth-integrated CO photoproduction is of the order of ∼38--57TgC - CO.yr-1, in excellent agreement with the results of Zafiriou et al. (2003) (30--70TgC - CO.yr-1) and confirming marine photochemistry as a minor source of CO to the atmosphere. (Abstract shortened by UMI.)... |
