Variability of Marine CDOM and Chlorophyll Fields Near Barrow, Alaska

Stephen R Okkonen, University of Alaska Fairbanks, Fairbanks, AK, United States, Robert G Campbell, University of Rhode Island Narragansett Bay, Narragansett, RI, United States and Carin J Ashjian, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
Late summer (2005-2015) in situ measurements of CDOM and chlorophyll fluorescence acquired from the western Beaufort shelf near Barrow, Alaska show that the pigment concentrations vary in response to changes in local river discharge and wind conditions. When winds are weak and shelf waters are stratified, the highest concentrations of CDOM and chlorophyll are often observed near bottom or at mid-depth. Under moderate-to-strong prevailing easterly winds, Ekman transport moves nearshore waters seaward, the water column becomes well-mixed and pigment concentrations increase in surface waters over the outer shelf. Because decaying tundra vegetation is the principal source of local CDOM, the correlation between CDOM and chlorophyll pigment concentrations decreases with increasing river discharge. These results have implications for satellite-based characterization of the nearshore Arctic marine environment and for designing the proposed field component of the NASA Arctic-COLORS Program.