Accession Number:

ADA609700

Title:

Colored Dissolved Organic Matter Dynamics in the Northern Gulf of Mexico from Ocean Color and Numerical Model Results

Descriptive Note:

Journal article

Corporate Author:

NAVAL RESEARCH LAB STENNIS DETACHMENT STENNIS SPACE CENTER MS OCEANOGRAPHY DIV

Report Date:

2013-12-18

Pagination or Media Count:

17.0

Abstract:

Colored dissolved organic matter CDOM absorption and salinity relationships were assessed and used in conjunction with the salinity and current outputs of a numerical model Navy Coastal Ocean Model NCOM to study CDOM dynamics in the northern Gulf of Mexico. In situ CDOM absorption and salinity obtained from multiple field campaigns were inversely correlated seasonally winter spring and summer and latitudinally inner- and outer-shelf zones, suggesting conservative behavior of CDOM distribution. A weaker correlation, during summer in the outer-shelf zone, however, indicated stronger effects of photooxidation and lower masking effects from riverine CDOM. Applying these relationships to simulated salinity resulted in hourly maps of CDOM that revealed similarities to CDOM patterns derived from SeaWiFS satellite imagery. Further, matchup comparisons between model-derived and in situ CDOM absorption were statistically sound for the summer bias 0.016, root mean square error 0.059, r2 0.51 SI 0.28 and the winter spring periods bias 0.033, root mean square error 0.099, r2 0.52, SI 0.21. Overlaying the model-derived CDOM maps on the simulated currents revealed the strong influence of currents on CDOM advection. Downcoast currents during the nonsummer months led to persistent advection of CDOM westward interrupted by frequent cold front events that flush CDOM-laden waters out of the coastal bays onto the inner and outer continental shelves. In contrast, the upcoast current regime, though less well organized, produces a more significant seaward advection of CDOM, likely due to the Ekman transport and subsequent entrainment by mesoscale eddies over the continental slope.

Subject Categories:

  • Biological Oceanography
  • Physical and Dynamic Oceanography
  • Hydrology, Limnology and Potamology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE