Brenner Samuel D.

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Last Name
Brenner
First Name
Samuel D.
ORCID
0000-0002-0826-1294

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  • Article
    A warm jet in a cold ocean
    (Nature Research, 2021-04-23) MacKinnon, Jennifer A. ; Simmons, Harper L. ; Hargrove, John ; Thomson, Jim ; Peacock, Thomas ; Alford, Matthew H. ; Barton, Benjamin I. ; Boury, Samuel ; Brenner, Samuel D. ; Couto, Nicole ; Danielson, Seth L. ; Fine, Elizabeth C. ; Graber, Hans C. ; Guthrie, John D. ; Hopkins, Joanne E. ; Jayne, Steven R. ; Jeon, Chanhyung ; Klenz, Thilo ; Lee, Craig M. ; Lenn, Yueng-Djern ; Lucas, Andrew J. ; Lund, Björn ; Mahaffey, Claire ; Norman, Louisa ; Rainville, Luc ; Smith, Madison M. ; Thomas, Leif N. ; Torres-Valdes, Sinhue ; Wood, Kevin R.
    Unprecedented quantities of heat are entering the Pacific sector of the Arctic Ocean through Bering Strait, particularly during summer months. Though some heat is lost to the atmosphere during autumn cooling, a significant fraction of the incoming warm, salty water subducts (dives beneath) below a cooler fresher layer of near-surface water, subsequently extending hundreds of kilometers into the Beaufort Gyre. Upward turbulent mixing of these sub-surface pockets of heat is likely accelerating sea ice melt in the region. This Pacific-origin water brings both heat and unique biogeochemical properties, contributing to a changing Arctic ecosystem. However, our ability to understand or forecast the role of this incoming water mass has been hampered by lack of understanding of the physical processes controlling subduction and evolution of this this warm water. Crucially, the processes seen here occur at small horizontal scales not resolved by regional forecast models or climate simulations; new parameterizations must be developed that accurately represent the physics. Here we present novel high resolution observations showing the detailed process of subduction and initial evolution of warm Pacific-origin water in the southern Beaufort Gyre.
  • Article
    Comparing observations and parameterizations of ice-ocean drag through an annual cycle across the Beaufort Sea
    (American Geophysical Union, 2021-03-29) Brenner, Samuel D. ; Rainville, Luc ; Thomson, Jim ; Cole, Sylvia T. ; Lee, Craig M.
    Understanding and predicting sea ice dynamics and ice-ocean feedback processes requires accurate descriptions of momentum fluxes across the ice-ocean interface. In this study, we present observations from an array of moorings in the Beaufort Sea. Using a force-balance approach, we determine ice-ocean drag coefficient values over an annual cycle and a range of ice conditions. Statistics from high resolution ice draft measurements are used to calculate expected drag coefficient values from morphology-based parameterization schemes. With both approaches, drag coefficient values ranged from ∼1 to 10 × 10−3, with a minimum in fall and a maximum at the end of spring, consistent with previous observations. The parameterizations do a reasonable job of predicting the observed drag values if the under ice geometry is known, and reveal that keel drag is the primary contributor to the total ice-ocean drag coefficient. When translations of bulk model outputs to ice geometry are included in the parameterizations, they overpredict drag on floe edges, leading to the inverted seasonal cycle seen in prior models. Using these results to investigate the efficiency of total momentum flux across the atmosphere-ice-ocean interface suggests an inter-annual trend of increasing coupling between the atmosphere and the ocean.
  • Article
    Acoustic sensing of ocean mixed layer depth and temperature from uplooking ADCPs
    (American Meteorological Society, 2023-01-01) Brenner, Samuel ; Thomson, Jim ; Rainville, Luc ; Torres, Daniel ; Doble, Martin ; Wilkinson, Jeremy ; Lee, Craig
    Properties of the surface mixed layer (ML) are critical for understanding and predicting atmosphere–sea ice–ocean interactions in the changing Arctic Ocean. Mooring measurements are typically unable to resolve the ML in the Arctic due to the need for instruments to remain below the surface to avoid contact with sea ice and icebergs. Here, we use measurements from a series of three moorings installed for one year in the Beaufort Sea to demonstrate that upward-looking acoustic Doppler current profilers (ADCPs) installed on subsurface floats can be used to estimate ML properties. A method is developed for combining measured peaks in acoustic backscatter and inertial shear from the ADCPs to estimate the ML depth. Additionally, we use an inverse sound speed model to infer the summer ML temperature based on offsets in ADCP altimeter distance during open-water periods. The ADCP estimates of ML depth and ML temperature compare favorably with measurements made from mooring temperature sensors, satellite SST, and from an autonomous Seaglider. These methods could be applied to other extant mooring records to recover additional information about ML property changes and variability.