Mack, L. K.. University of Washington, lmack@ocean.washington.edu
, . K.. ,

 
INTENSIVELY LEARNING OPTICAL OCEANOGRAPHY: CDOM ABSORPTION AND ITS EFFECT ON REMOTELY-SENSED REFLECTANCE MODELED WITH HYDROLIGHT 4.0
 
Absorption by colored dissolved organic matter (CDOM) as high as 0.4 per meter at 400 nm has been reported in marine waters of Washington. As a consequence, CDOM has a significant effect on the magnitude and spectral shape of water-leaving radiances. Variability in CDOM absorption coefficients between East Sound, Orcas Island, and the Strait of Juan de Fuca was investigated with discrete water samples and an in situ, profiling spectrometer. Discrete water samples were filtered in the laboratory and analyzed with a 10-cm pathlength in an Aminco DW-2 spectrophotometer. Absorption coefficients obtained from in-situ filtration of seawater with a WETLabs ac9 compared well with those from discrete samples, indicating acceptable instrument closure. Variability in the magnitude and slope coefficient for CDOM absorption did not appear to be a function of salinity, although absorption coefficients at 400 nm varied between 0.22 and 0.36 per meter. Two bio-optical models, one using the chlorophyll profile and the second using the chlorophyll profile and CDOM absorption were tested using HYDROLIGHT 4.0. The modeled remote-sensing reflectance varied spectrally by factors of 3 to 11 indicating that the bio-optical models are not adequate for these waters due to high absorption by CDOM and relatively low particulate backscatter.
 
Day: Thursday, Feb. 4
Time: Poster
Location: Sweeney Center
 
Code: SS53TH0993S