Comparison with observations

Northern Gulf of Mexico Hybrid Coordinate Ocean Model (NGoM-HYCOM)
Comparison with observations

In collaboration with Nan D. Walker (Dept. of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, Louisiana ), chlorophyll asatellite images from the Indian Oceansat-1 Ocean Color Monitor (OCM) are used to make qualitative comparisons between observed and modeled events of interaction between the Loop Current and the Mississippi River plume. These chlorophyll aestimates are effective for tracking the motion of near-surface, nutrient-rich river waters in the northern Gulf of Mexico.

(A):Snapshot of model surface salinity and sea surface height + surface velocity vectors on May 28th, 2005,  when the Loop Current System (LC) interacted with the Mississippi River plume. (B)Oceansat-1 OCM chlorophyll aimages on the same day. The chlorophyll ascale ranges from 0 to 3 mg m-3. River water is depicted in red/brown tones near the mouth of rivers, where pigment concentrations are highest and orange/yellow tones in deep water, where pigment concentrations are reduced.

The satellite image demonstrate the remarkable impact of the LC system over the transport of the MR plume. A distinct chlorophyll a band extending into the GoM, which agrees with the LC conditions during this period. The model surface salinity on the same day shows the presence of the low-salinity band just to the east of the delta, in agreement with the position of the chlorophyll a band across the shelfbreak. The satisfactory comparison reinforces the necessity to employ a modeling approach that uses lateral boundary conditions from a realistic, data-assimilative ocean model, in order to capture strong interactions between the MR plume and the Loop Current.