Role of Baroclinic Processes on Flushing Characteristics in a Highly Stratified Estuarine System, Mobile Bay, Alabama Academic Article uri icon

abstract

  • 2018. American Geophysical Union. All Rights Reserved. Flushing of an estuary quantifies the overall water exchange between the estuary and coastal ocean and is crucially important for water quality as well as biological and geochemical processes within the system. Flushing times and freshwater age in Mobile Bay were numerically calculated under realistic and various controlled forcing conditions. Their responses to external forcing were explained by the three-dimensional characteristics of general circulation in the system. The flushing time ranges from 10 to 33days under the 25th75th percentile river discharges, nearly half of the previous estimates based on barotropic processes only, suggesting the important contribution of baroclinic processes. Their influence, quantified as the new ocean influx, is on the same order of the river discharge under low to moderate river discharge conditions. The baroclinic influence increases and then decreases with increasing river discharge, aligning with the response of horizontal density gradient. By enhancing the net influx from the ocean mainly through density-driven circulation, baroclinic processes contribute to reduce flushing times. The three-dimensional circulation, which differs greatly between the wet and dry seasons, explains the temporal and spatial variations of the flushing characteristics. Wind forcing influences the three-dimensional circulation in the system with easterly and northerly winds tending to reduce the flushing time, while southerly and westerly winds the opposite.

published proceedings

  • JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS

altmetric score

  • 0.25

author list (cited authors)

  • Du, J., Park, K., Shen, J., Dzwonkowski, B., Yu, X., & Yoon, B. I.

citation count

  • 29

complete list of authors

  • Du, Jiabi||Park, Kyeong||Shen, Jian||Dzwonkowski, Brian||Yu, Xin||Yoon, Byung Il

publication date

  • July 2018