Houghton Robert

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Houghton
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Robert
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Now showing 1 - 4 of 4
  • Technical Report
    The 1974 ALVIN dives on Corner Rise and New England seamounts
    (Woods Hole Oceanographic Institution, 1977-02) Heirtzler, James R. ; Taylor, P. T. ; Ballard, Robert D. ; Houghton, Robert L.
    During the summer of 1974 an ALVIN dive was made on Corner Rise, and Nashville, Gilliss, Rehoboth, Manning, Balanus and Mytilus Seamounts. The principal characteristics of the topography, sediments and rocks were observed and recorded.
  • Article
    A model-dye comparison experiment in the tidal mixing front zone on the southern flank of Georges Bank
    (American Geophysical Union, 2008-02-09) Chen, Changsheng ; Xu, Qichun ; Houghton, Robert ; Beardsley, Robert C.
    A process-oriented model-dye comparison experiment was conducted to examine the ability of a numerical ocean model to simulate the observed movement of dye across the tidal mixing front on the southern flank of Georges Bank during 22–26 May 1999. The experiment was made using the unstructured-grid Finite-Volume Coastal Ocean Model (FVCOM) with varying horizontal resolution. The results indicate that the observed cross-isobath movement of the dye patch was primarily controlled by meso-scale temporal and spatial variability of the water temperature and salinity fields. Onset of vertical stratification tended to slow down an upward stretching of the dye column and trapped the dye within the bottom mixed layer. To reach a convergent numerical solution that reproduced the observed lateral turbulent dispersion of dye, the FVCOM grid required a horizontal resolution of ∼500 m in the dye study region. Within the tidal mixing front of Georges Bank, the movement of the center of the dye patch was mainly driven by the ensemble velocity integrated over the dye volume, with a first-order contribution from vertical shear of the dye's horizontal velocity.
  • Article
    Estuarine boundary layer mixing processes : insights from dye experiments
    (American Meteorological Society, 2007-07) Chant, Robert J. ; Geyer, W. Rockwell ; Houghton, Robert ; Hunter, Elias J. ; Lerczak, James A.
    A series of dye releases in the Hudson River estuary elucidated diapycnal mixing rates and temporal variability over tidal and fortnightly time scales. Dye was injected in the bottom boundary layer for each of four releases during different phases of the tide and of the spring–neap cycle. Diapycnal mixing occurs primarily through entrainment that is driven by shear production in the bottom boundary layer. On flood the dye extended vertically through the bottom mixed layer, and its concentration decreased abruptly near the base of the pycnocline, usually at a height corresponding to a velocity maximum. Boundary layer growth is consistent with a one-dimensional, stress-driven entrainment model. A model was developed for the vertical structure of the vertical eddy viscosity in the flood tide boundary layer that is proportional to u2*/N∞, where u* and N∞ are the bottom friction velocity and buoyancy frequency above the boundary layer. The model also predicts that the buoyancy flux averaged over the bottom boundary layer is equal to 0.06N∞u2* or, based on the structure of the boundary layer equal to 0.1NBLu2*, where NBL is the buoyancy frequency across the flood-tide boundary layer. Estimates of shear production and buoyancy flux indicate that the flux Richardson number in the flood-tide boundary layer is 0.1–0.18, consistent with the model indicating that the flux Richardson number is between 0.1 and 0.14. During ebb, the boundary layer was more stratified, and its vertical extent was not as sharply delineated as in the flood. During neap tide the rate of mixing during ebb was significantly weaker than on flood, owing to reduced bottom stress and stabilization by stratification. As tidal amplitude increased ebb mixing increased and more closely resembled the boundary layer entrainment process observed during the flood. Tidal straining modestly increased the entrainment rate during the flood, and it restratified the boundary layer and inhibited mixing during the ebb.
  • Dataset
    Hudson River estuary 2002 field experiment: moorings
    (Woods Hole Oceanographic Institution, 2023-09-20) Geyer, W. Rockwell ; Chant, Robert J. ; Houghton, Robert ; Lerczak, James A. ; Hunter, Elias J. ; Conley, Margaret
    This dataset includes data from moorings deployed in the Hudson River estuary during the spring of 2002. The moorings were deployed at Spuyten Duyvil for 43 days and included a cross-channel array of temperature and conductivity sensors as well as 4 upward-looking ADCPs and 2 pressure sensors flanking the channel.