Climate, Weather, and Physical-Biological Coupling Research in a Great Lakes Context

Abstract

This presentation will be divided into three parts. The first part will introduce the Great Lakes Environmental Research Laboratory in Ann Arbor, Michigan and its Lake Michigan Field Station in Muskegon, Michigan. Its facilities and research activities will be summarized.

The second part will present research on the impacts of global climate change on lake levels. A number of studies have been carried out over the years to look at this question. Most of these have used a simple de-biasing scheme for ingesting GCM data into an offline hydrologic model. Studies using this method have generally shown a decrease in lake net basin supply and a consequent drop in lake levels as a result of enhanced greenhouse gas concentration. Other studies have used the water budget directly from GCM runs and found an increase in net basin supply for the Great Lakes/St. Lawrence River basin. The study highlighted here uses a regional climate model with the Great Lakes fully coupled to the atmosphere, and results in increased net basin supply. Each of these methods has factors in its favor and against it.

The third part will present research on the influence of surface roughness on the quantity and location of lake effect precipitation. Using another version of the coupled regional-scale model, the simulation of a particular case of lake effect precipitation was analyzed under conditions of realistic (standard) roughness and surface roughness corresponding to tall grass (the grass roughness case. The grass roughness case yields a smaller overall amount of precipitation, but it also changes the spatial distribution, moving more of the precipitation farther away from the shore, and may put more of the water in different drainage basins.

Throughout the presentation, I will highlight potential modes of physical-biological coupling, point out ways in which GLERL and ESRL can mutually benefit through cooperation, and seek input toward making my visit to ESRL worthwhile.