Guest Brian J.

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Brian J.
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  • Other
    Brazil Basin Tracer Release Experiment
    (Woods Hole Oceanographic Institution, 2021-04) Ledwell, James R. ; Donoghue, Terence ; Guest, Brian J. ; Lemmond, Peter ; Sellers, Cynthia J. ; Cortes, Norbert
    The purpose of the Brazil Basin Tracer Release Experiment is to measure diapycnal (across isopycnal) mixing and epipycnal (along-isopycnal) mixing and stirring in the deep ocean. This cruise is the fourth in the overall experiment. In the first cruise in early 1996, 110 kg of sulfur hexafluoride (SF6) were released on an isopycnal surface near 4000 meters depth in the eastern part of the basin on the flanks of the Mid-Atlantic Ridge (MAR). The location of the release was near 21.7 S, 18.4 W. The release site was over a zonal valley that leads to the MAR and is about 5000 m deep. The isopycnal surface of the release was defined as the surface on which the potential density anomaly, referenced to 4000 dbar pressure, was 45.9408 kg/m3. The release streaks and results of initial sampling in 1996 are described in Polzin et al. [1997].
  • Technical Report
    R/V Seward Johnson cruise report (SJ-9807), ACCE S-PALACE float deployments
    (Woods Hole Oceanographic Institution, 1999-02) Montgomery, Ellyn T. ; Guest, Brian J.
    R/V Seward Johnson cruise 98-07 occurred between October 12 and November 5, 1998. The goal of the cruise was to deploy 30 Salinity Profiling Autonomous Lagrangian Current Explorer (S-PALACE) floats in the tropical Atlantic as part of the Atlantic Circulation and Climate Experiment (ACCE). These floats are neutrally buoyant and drift with the water in which they are deployed. They are programmed to obtain temperature and salinity profiles of the top 1000 meters of the ocean every ten days. To ascertain the validity of the float data, a CTD profile was made at the site and time of deployment of each float. The data from these floats augments data already being obtained from ten floats deployed last year. Given 40 floats in the tropical North Atlantic, reporting every 10 to 14 days with an expected operational life of 3-5 years, we hope to gather 5000 to 7000 profiles from these floats in the coming years. The temperature and salinity profiles, along with derived properties will aid in examining the mechanisms of upper ocean heat and freshwater storage. This data, combined with satellite sea surface should provide useful input to climate and weather prediction models.
  • Technical Report
    Low-rate discharge of various electrochemical batteries for use with oceanographic instruments
    (Woods Hole Oceanographic Institution, 1985-04) Ciesluk, Alfred J. ; Guest, Brian J. ; Marquette, Craig D. ; Tupper, George H.
    The endurance of self-sustained oceanographic instruments is generally limited to battery energy. Tests were initiated to measure the capacities of several types of electrochemical batteries when discharged at temperatures and rates typical of oceanographic use. Battery systems represented are alkaline-manganese dioxide, mercuric-oxide, and lithium sulphur oxychloride. Results of tests completed so far are presented. A brief overview of those batteries best suited for use with self-sustained oceanographic instruments is included as an appendix.
  • Technical Report
    Shearmeter floats in the area of the WHOI Brazil Basin Tracer Release Experiment : technical and oceanographic data
    (Woods Hole Oceanographic Institution, 2002-01) Duda, Timothy F. ; Guest, Brian J. ; Wooding, Christine M. ; Jones, Clayton M. ; Lelievre, Scott ; Webb, Douglas C.
    Six drifting floats designed to measure shear were deployed in the vicinity of the Brazil Basin Tracer Release Experiment. The one-year long time series of oceanographic conditions obtained by the floats are for direct comparison with long-term tracer dispersion. The purpose of the tracer dispersion experiment was to study mixing of Antarctic Bottom Water at approximately 4000 m depth with less dense water above. Two of the floats returned shear records, one from about 1660 m depth and one from about 2800 m depth. Mean shear at 1660 m was 2.2 x 10 -3 s-1 with N = 1.1 cph, about 1.9 times the Garrett-Munk model amount. Mean shear at 2800 m was 1.1 x 10-3 with N = 0.5 cph, about 2.2 times Garrett-Munk. There was no apparent depth structure to the shear recorded by the near-bottom float moving over the mountainous seafloor. The two shear time series and the local tidal velocities were not strongly correlated, but the tide and shear series did have some similarities. Some variability in the 1660-m shear may be due to atmospheric forcing. Three floats deeper than 2800 m returned one-year long trajectories. Two trajectories were persistently eastward.