Purdue Water Community

Lecture by Wentao Liu, Postdoctoral Scholar

September 18 @ 4:30 PM - 5:30 PM -

"Three dimensional modeling of the effects of changes in meteorological forcing on the thermal structure and dissolved oxygen in Lake Erie"

Wentao Liu, Postdoctoral Scholar   
Wednesday, September 18, 4:30pm (HAMP 1113)

Abstract: Global warming and resulting changes in meteorological forcing are anticipated to significantly affect the Laurentian Great Lakes ecosystem in many different ways. A three-dimensional hydrodynamic and aquatic ecological coupled model ELCOM-CAEDYM, validated by the field data collected in 2008, is first used to investigate the responses of the thermal structure and dissolved oxygen concentration in Lake Erie to potential changes in air temperature and wind speed. A new method is presented to define spatially and temporally varying regions for the epilimnion, thermocline, and hypolimnion. Four metrics are selected to quantify the characteristics of the thermal structure: mean epilimnion temperature, mean hypolimnion temperature, onset and breakdown of stratification, and thermocline depth. Exploiting the power of the three dimensional model to provide a more authentic characterization of thermal structure in such large lakes, it is shown that patterns inferred from simple isotherm dynamics, as typically done with one dimensional models, are not always accurate. In the dissolved oxygen studies similar analyses are presented. Three factors related to lake hydrodynamics have strong influences on hypolimnetic hypoxia: water temperature, stratification duration, and hypolimnion thickness. In a warm and quiescent year the hypolimnetic hypoxia will likely become more severe if considering the effects of meteorological forcing changes only. The present results show the potential for complicated and interactive effects of climate forcing on important biogeochemical processes in Lake Erie as well as other large mid-latitude lakes.

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