151 research outputs found
Lake Granbury and Lake Whitney Assessment Initiative
A team of Texas AgriLife Research, Baylor University and University of Texas at
Arlington researchers studied the biology and ecology of Prymnesium parvum (golden
algae) in Texas lakes using a three-fold approach that involved system-wide monitoring,
experimentation at the microcosm and mesocosm scales, and mathematical modeling.
The following are conclusions, to date, regarding this organism’s ecology and potential
strategies for mitigation of blooms by this organism
Investigating summer thermal stratification in Lake Ontario
Summer thermal stratification in Lake Ontario is simulated using the 3D
hydrodynamic model Environmental Fluid Dynamics Code (EFDC). Summer temperature
differences establish strong vertical density gradients (thermocline) between the epilimnion
and hypolimnion. Capturing the stratification and thermocline formation has been a
challenge in modeling Great Lakes. Deviating from EFDC's original Mellor-Yamada (1982)
vertical mixing scheme, we have implemented an unidimensional vertical model that uses
different eddy diffusivity formulations above and below the thermocline (Vincon-Leite,
1991; Vincon-Leite et al., 2014). The model is forced with the hourly meteorological data
from weather stations around the lake, flow data for Niagara and St. Lawrence rivers; and
lake bathymetry is interpolated on a 2-km grid. The model has 20 vertical layers following
sigma vertical coordinates. Sensitivity of the model to vertical layers' spacing is thoroughly
investigated. The model has been calibrated for appropriate solar radiation coefficients and
horizontal mixing coefficients. Overall the new implemented diffusivity algorithm shows
some successes in capturing the thermal stratification with RMSE values between 2-3°C.
Calibration of vertical mixing coefficients is under investigation to capture the improved
thermal stratification
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