Bowen Melissa M.

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Bowen
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Melissa M.
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  • Technical Report
    Stress, salt flux, and dynamics of a partially mixed estuary
    (Woods Hole Oceanographic Institution, 1998-08) Fredericks, Janet J. ; Trowbridge, John H. ; Geyer, W. Rockwell ; Williams, Albert J. ; Bowen, Melissa M. ; Woodruff, Jonathan D.
    A field study was performed in the lower Hudson River, a partially mixed estuary with a relatively simple geometry (Figure 1), between August and October of 1995. The objectives of the study were (1) to quantify and characterize the turbulent transport of momentum and salt, and (2) to relate the turbulent transport processes to the local and estuary-wide dynamics. The measurement program consisted of fixed and shipboard components. At a central site, a moored array of temperature-conductivity sensors and optical backscatter sensors (OBS), a bottom-mounted acoustic Doppler current profiler (ADCP), and a bottom-mounted array of acoustic travel-time current sensors (BASS), temperature-conductivity sensors, and OBS sensors resolved the vertical structure of velocity, salinity and turbidity and the near-bottom turbulence structure. Moored and bottom-mounted velocity, temperature, conductivity and pressure sensors at five secondary sites quantified the spatial and temporal variabilty of velocity, salinity and bottom pressure. Shipboard measurements with an ADCP and a conductivity-temperature-depth (CTD) profiler, accompanied by an OBS sensor, resolved the spatial structure and tidal variability of velocity, salinity and turbidity along several cross-channel and along-channel transects. This report describes the measurements in detail. Section II describes the instrumentation, Section III describes the deployment and sampling schemes, Section IV describes the data processing, and Section V is a summary of plots of selected data. Section VI documents the data files and Sections VII and VII give acknowledgments and references.
  • Thesis
    Mechanisms and variability of salt transport in partially-stratified estuaries
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2000-02) Bowen, Melissa M.
    The variability of salt transport determines the variation of the length of the salinity intrusion and the large-scale density gradient in an estuary. This thesis contains three studies that address salt transport and the salt balance. The variation of salt transport with the depth, the along-channel salinity gradient, and the amplitude of the tidal velocity is investigated with analytic and numerical models. The results indicate that salt transport increases dramatically during stratified periods when vertical mixing is weak. Analysis of salt transport from observations in the Hudson Estuary show that stratified periods with elevated estuarine salt transport occur in five-day intervals once a month during apogean neap tides. Oscillatory salt transport, which is hypothesized to be primarily caused by lateral exchange and mixing of salt, appears to play a more minor role in the salt balance of the estuary. The salt balance of the estuary adjusts very little to the spring-neap modulation of salt transport but adjusts rapidly to pulses of freshwater flow. A simple model is used to investigate the process and time scales of adjustment of the salt balance by connecting variations of salt transport to the variations of freshwater flow and vertical mixing. The results show the length of the salinity intrusion adjust via advection to rapid and large increases in freshwater flow. The salinity intrusion adjusts more rapidly to the spring-neap cycle of tidal mixing the higher the freshwater flow.