Numerical Experiment of Stratification Induced by Diurnal Solar Heating Over the Louisiana Shelf
The effect of diurnal solar heating on the stratification of waters over the Louisiana shelf was examined using the 3-dimensional Finite Volume Community Ocean Model (FVCOM). The simulation was for June 2009 to examine the effects of solar heating on summertime stratification. The input components of solar radiation to the FVCOM model were calculated using available relationships for shortwave, longwave, latent heat, and sensible heat radiation and using Metocean field data obtained from WAVCIS stations. Simulation results showed a continuous increase in water temperature and stratification during June 2009 with daily fluctuations of sea surface temperature as large as 0.9 °C. The corresponding stratification strengthening was quantified by an increase in the gradient Richardson number and buoyancy frequency. Development of shelf-wide stratification coincided with a significant decline in bottom water oxygen concentration. Our results demonstrate how, under certain conditions, solar heating can significantly contribute to vertical stratification and may also create conditions conducive to the formation and persistence of hypoxia.
KeywordsNumerical modeling Solar radiation Stratification Hypoxia FVCOM Louisiana shelf Gulf of Mexico
The authors are grateful to Nancy Rabalais for sharing the dissolved oxygen data from WAVCIS-CSI-6 and Changsheng Chen for providing the FVCOM.
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