Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4548275 | Journal of Marine Systems | 2012 | 13 Pages |
A three-dimensional hydrodynamic model is applied to the Mobile Bay system to study water and salt exchange with the northern Gulf of Mexico via Main Pass (MP) and eastern Mississippi Sound via Pass-aux-Herons (PaH). On average, more water leaves the Bay through MP than through PaH, and the Bay gains salt through MP and loses about the same amount through PaH. However, the volume discharge rate Qf and salt transport rate FS vary greatly in response to wind and river discharge with the range of variation 1–2 orders of magnitude larger than the corresponding mean. Stratification plays a key role for salt transport through MP. During periods of large river discharge, the landward shear dispersive transport FE peaking during equatorial tides and the landward tidal oscillatory transport FT peaking during tropic tides, respectively, balance the seaward advective transport QfS0. During periods of relatively weak stratification, FS at MP is almost entirely determined by QfS0 and its variability is well correlated with north–south (along-estuary) wind, associated with the barotropic (water level) adjustment. At the shallow, weakly stratified PaH, FS is almost identical to QfS0, and Qf is well correlated with east–west wind, with the correlation becoming stronger during the dry period.
► We apply a three-dimensional hydrodynamic model to the tidal Mobile Bay system to study the water and salt exchange. ► Stratification plays a key role for salt transport through the deep ship channel. ► Under strong stratification, the shear dispersive and tidal oscillatory salt transport balance the advective salt transport. ► Under weak stratification, the advective salt transport, correlated with along-estuary wind, dominates the salt transport.