The Impact of Episodic Events on Nearshore-offshore Transport in the Great Lakes: Hydrodynamic Modeling Program

PIs: David J. Schwab and Dmitry Beletsky

Objectives:

The main objective of this proposal is to identify and quantify the physical processes generating nearshore- offshore transport of biogeochemically important materials in the Great Lakes during episodic events by applying a coupled ice-circulation model to Lake Michigan. The specific objectives include:

Approach:
  1. Ice Modeling - develop Great Lakes Ice Model
  2. Circulation Modeling - apply Great Lakes version of Princeton Ocean Model to Lake Michigan for EEGLE study years
  3. Wave Modeling - apply GLERL/Donelan Wave Model to Lake Michigan for EEGLE study years
  4. Integration with Sediment Transport Modeling and Lower Food Web Modeling Projects
Results:
  1. The spectacular eddy-like plume that occurred during the 1998 EEGLE pilot year was used as a case study for coupled hydrodynamic/wave/sediment transport and coupled hydrodynamic/biological models. The case studies confirmed the episodic nature of lake circulation and sediment transport in the lake as well as identifying light limitation from suspended material in the plume region as a critical factor in primary production.
  2. The combination of high waves and the two-gyre circulation pattern in southern Lake Michigan during storms with northerly winds appears to be responsible for the asymmetric distribution of bottom sediments in the lake.
  3. During the unusually warm EEGLE pilot year and field years the role of ice in plume formation was a negligible factor so the work on developing a Great Lakes ice model was postponed.
Collaborators: Roebber, Saylor et al., Vesecky, Budd et al., Bedford et al., Chen