Analysis of apparent optical properties and ocean color models using measurements of seawater constituents in New England continental shelf surface waters
Green, Rebecca E.
Sosik, Heidi M.
MetadataShow full item record
We used budgets of absorption (a), scattering (b), and backscattering (bb) for particles and chromophoric dissolved organic matter (CDOM) to investigate sources of seasonal variations in apparent optical properties (AOPs) of New England continental shelf surface waters. Spectral a, b, and bb budgets for particles were estimated from flow cytometric measurements of eukaryotic pico/nanophytoplankton, Synechococcus, heterotrophic prokaryotes, detritus, and minerals; AOPs were modeled with Hydrolight radiative transfer software. For late summer and spring, our modeled values of the diffuse attenuation coefficient (Kd) and remote sensing reflectance (Rrs) were on average within 15% and 9%, respectively, of independent measurements. This close agreement allowed us to examine how different seawater constituents contributed to AOP variability. Higher values of Kd in the spring, compared to summer, were due to higher absorption by eukaryotic phytoplankton (aeuk) and CDOM (aCDOM), which coincided with higher nutrient levels and less stratified conditions than in the summer. Differences in the spectral shape of Rrs between the seasons were caused by a combination of differences in aeuk, aCDOM, and bb from non-phytoplankton particles (minerals and detritus combined). For non-phytoplankton bb the major seasonal difference was a higher inverse wavelength dependence in the summer due to the effects of small organic detritus. We applied two semianalytical ocean color models to our data, in order to evaluate whether the assumptions and parameterizations inherent in these models are applicable for New England shelf waters. We show how differences between observed and modeled chlorophyll a specific phytoplankton absorption, aCDOM, and non-phytoplankton bb cause errors in chlorophyll a concentration and IOPs retrieved from reflectance inversion models.
Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 109 (2004): C03026, doi:10.1029/2003JC001977.
Showing items related by title, author, creator and subject.
Green, Rebecca E. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2002-06)Predictions of chlorophyll concentration from satellite ocean color are an indicator of phytoplankton primary productivity, with implications for foodweb structure, fisheries, and the global carbon cycle. Current models ...
Coastal ocean circulation influences on remotely sensed optical properties : a West Florida Shelf case study Weisberg, Robert H.; He, Ruoying; Kirkpatrick, Gary; Muller-Karger, Frank E.; Walsh, John J. (Oceanography Society, 2004-06)Satellite-sensed ocean optical features are derived from a combination of factors, including the concentration of water properties by the ocean circulation and the modifications of these properties by biological and ...
Siegel, David A.; Peterson, P.; McGillicuddy, Dennis J.; Maritorena, S.; Nelson, N. B. (American Geophysical Union, 2011-07-14)We investigate the bio-optical footprints made by mesoscale eddies in the Sargasso Sea and the processes that create them through an eddy-centric approach. Many (>10,000) eddies are identified and followed in time using ...