Marine Ecosystem Dynamics Modeling Laboratory

Superior Lake ECOM-si

The ECOM-si based Lake Superior model was developed when KITES started. At that time, this model was the best choice. We did failed to capture the magnitude of the Keweenaw Current using the original orthoginal grid version of ECOM-si because the current jet was so close to the coast. For this season, we modified ECOM-si by introducing a non-orthogonal curvilinear coordinate system that provide more flexible to fit the local irregular coastal geometry along the Keweenaw Peninsula. This model was robust for the process-oriented study of the eddy formation and Keweenaw Current in the local scale. The major results of this model are described below.

Eddy formation

This experiment was made by running the model as the density adjustment problem based on an initial field specified using the June 1973 hydrographic survey data. The results show that the Keweenaw thermal front is baroclinically unstable, which leads to the formation of the anticyclonic eddies along the coast and headland of the Peninsula.

Click the image on the right to view the animation

July 1973 simulation

This experiment was made by driving the model using the wind observed at Eggle harbor. The initial condition of water temperature was specified using the June climatological hydrographic field. The model results were validated by a direct comparison with the current measurement data.

Click the image on the right to view the animation

July 1973 simulation-cross-shore section

This is the animation showing the vertical variation of the water temperature on a cross-shore section of the Keweenaw Peninsula during the July 1973 simulation.

Click the image on the right to view the animation

July 1973 particle tracking experiments

A column of particles were released in the upstream region of Keweenaw Peninsula and tracked under the real-time wind condition. This experiment was to examine the cross-frontal water exchange in the Keweenaw thermal frontal zone.

Click the image on the right to view the animation

The same particle tracking experiment as shown above except the different releasing site. This one clearly showed tha a significant cross-frontal water exchange could occur the region with offshore extended bottom slope.

Click the image on the right to view the animation

The 1999 sumulation results

The 1999 simulation was conducted by forcing the Ecom-si using the real-time wind field and empirical estimation of the surface heat flux.The surface heat flux was adjusted by the best matching the surface water temperature observed at 4 meteorological buoys. The model captured a general seasonal pattern of the Keweenaw Current, but failed to reproduce the magnitude of the current jet observed from ADCP data.

An experiment was then made to examine the response of the current to the meso-scale wind variability detected from the Quick-Scan wind data.

Some of the simulation results are posted on this website to provide a direct view of the seasonal variation of the current and water temperature in the lake.

Click here to go to the 1999 simulation page.

QuikScat wind experiments

The response of Lake Superior to the meso-scale variability of the wind field was examined by forcing the ECOM-si using the QuikeScat wind field recorded in 1999. The comparison results show that the meso-scale wind variability plays a major role in the temporal varability of the Keweenaw Current.

Click here to go to the QuikScat experiment page.

«PreviousNext» Posted on January 15, 2014