Weingartner
Thomas J.
Weingartner
Thomas J.
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ArticleMean and seasonal circulation of the eastern Chukchi Sea from moored timeseries in 2013-2014(American Geophysical Union, 2021-04-30) Tian, Fei ; Pickart, Robert S. ; Lin, Peigen ; Pacini, Astrid ; Moore, G. W. K. ; Stabeno, Phyllis J. ; Weingartner, Thomas J. ; Itoh, Motoyo ; Kikuchi, Takashi ; Dobbins, Elizabeth ; Bell, Shaun ; Woodgate, Rebecca ; Danielson, Seth L. ; Wang, ZhaominFrom late-summer 2013 to late-summer 2014, a total of 20 moorings were maintained on the eastern Chukchi Sea shelf as part of five independent field programs. This provided the opportunity to analyze an extensive set of timeseries to obtain a broad view of the mean and seasonally varying hydrography and circulation over the course of the year. Year-long mean bottom temperatures reflected the presence of the strong coastal circulation pathway, while mean bottom salinities were influenced by polynya/lead activity along the coast. The timing of the warm water appearance in spring/summer is linked to advection along the various flow pathways. The timing of the cold water appearance in fall/winter was not reflective of advection nor related to the time of freeze-up. Near the latitude of Barrow Canyon, the cold water was accompanied by freshening. A one-dimensional mixed-layer model demonstrates that wind mixing, due to synoptic storms, overturns the water column resulting in the appearance of the cold water. The loitering pack ice in the region, together with warm southerly winds, melted ice and provided an intermittent source of fresh water that was mixed to depth according to the model. Farther north, the ambient stratification prohibits wind-driven overturning, hence the cold water arrives from the south. The circulation during the warm and cold months of the year is different in both strength and pattern. Our study highlights the multitude of factors involved in setting the seasonal cycle of hydrography and circulation on the Chukchi shelf.
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ArticleThe St. Lawrence polynya and the Bering shelf circulation : new observations and a model comparison(American Geophysical Union, 2006-09-19) Danielson, Seth L. ; Aagaard, Knut ; Weingartner, Thomas J. ; Martin, S. ; Winsor, Peter ; Gawarkiewicz, Glen G. ; Quadfasel, Detlef R.Using 14 year-long instrumented moorings deployed south of St. Lawrence Island, along with oceanographic drifters, we investigate the circulation over the central Bering shelf and the role of polynyas in forming and disseminating saline waters over the shelf. We focus also on evaluating the Gawarkiewicz and Chapman [1995] model of eddy production within coastal polynyas. Principal results include: 1) The northern central shelf near-surface waters exhibit westward flow carrying low-salinity waters from the Alaskan coast in fall and early winter, with consequences for water mass formation and biological production. 2) Within the St. Lawrence polynya, the freshening effect of winter advection is about half as large as the salting effect of surface brine flux resulting from freezing. 3) Brine production over the Bering shelf occurs primarily offshore, rather than within coastal polynyas, even though ice production per unit area is much larger within the polynyas. 4) We find little evidence for the geostrophic flow adjustment predicted by recent polynya models. 5) In contrast to the theoretical prediction that dense water from the polynya is carried offshore by eddies, we find negligible cross-shelf eddy density fluxes within and surrounding the polynya and very low levels of eddy energy that decreased from fall to winter, even though dense water accumulated within the polynya and large cross-shore density gradients developed. 6) It is possible that dense polynya water was advected downstream of our array before appreciable eddy fluxes materialized.
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ArticleModeling winter circulation under landfast ice : the interaction of winds with landfast ice(American Geophysical Union, 2012-04-04) Kasper, Jeremy L. ; Weingartner, Thomas J.Idealized models and a simple vertically averaged vorticity equation illustrate the effects of an upwelling favorable wind and a spatially variable landfast ice cover on the circulation beneath landfast ice. For the case of no along-shore variations in ice, upwelling favorable winds seaward of the ice edge result in vortex squashing beneath the landfast ice leading to (1) large decreases in coastal and ice edge sea levels, (2) cross-shore sea level slopes and weak (<~.05 m s−1) under-ice currents flowing upwind, (3) strong downwind ice edge jets, and (4) offshore transport in the under-ice and bottom boundary layers of the landfast ice zone. The upwind under-ice current accelerates quickly within 2–4 days and then slows as cross-shore transport gradually decreases the cross-shore sea level slope. Near the ice edge, bottom boundary layer convergence produces ice edge upwelling. Cross-ice edge exchanges occur in the surface and above the bottom boundary layer and reduce the under-ice shelf volume by 15% in 10 days. Under-ice along-shore pressure gradients established by along- and cross-shore variations in ice width and/or under-ice friction alter this basic circulation pattern. For a landfast ice zone of finite width and length, upwelling-favorable winds blowing seaward of and transverse to the ice boundaries induce downwind flow beneath the ice and generate vorticity waves that propagate along-shore in the Kelvin wave direction. Our results imply that landfast ice dynamics, not included explicitly herein, can effectively convert the long-wavelength forcing of the wind into shorter-scale ocean motions beneath the landfast ice.
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DatasetCruise Event Logs from 15 vessels for 116 U.S. GLOBEC cruises from 1997-2004 in the Northeast Pacific and Gulf of Alaska areas (NEP program)(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2021-06-08) Barth, Jack ; Boldt, Jennifer L. ; Brodeur, Richard D ; Cokelet, Edward D. ; Cowles, Timothy ; Danielson, Seth L. ; Emmett, Robert L ; Farley, Edward V. ; Fleischbein, Jane ; Haldorson, Lewis J ; Hopcroft, Russell R. ; Huyer, Adriana ; Janout, Markus A. ; Kachel, Nancy ; Kondzela, Chris ; Moss, Jamal Hasan ; Musgrave, Dave ; Napp, Jeffrey ; Noskov, Jackie Popp ; Peterson, William T. ; Piccolo, Jack ; Royer, Thomas C. ; Smith, Robert ; Stockwell, Dean A. ; Strom, Suzanne ; Thornton, Sarah ; Tynan, Cynthia ; Weingartner, Thomas J. ; Coyle, Kenneth O ; Keister, Julie E. ; Sherr, EvelynCruise Event Logs from 15 vessels for 116 U.S. GLOBEC cruises from 1997-2004 in the Northeast Pacific and Gulf of Alaska areas For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/2341
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ArticleIntroduction to the special issue on the new Artic Ocean(Oceanography Society, 2022-12-08) Weingartner, Thomas ; Ashjian, Carin ; Brigham, Lawson ; Haine, Thomas ; Mack, Liza ; Perovich, Don ; Rabe, BenjaminOne hundred and thirty years ago, Fridtjof Nansen, the Norwegian polar explorer and scientist, set off on a bold three-year journey to investigate the unknown Arctic Ocean. The expedition relied on a critical technological development: a small, strong, and maneuverable vessel, powered by sail and an engine, with an endurance of five years for twelve men. His intellectual curiosity and careful observations led to an early glimpse of the Arctic Ocean’s circulation and its unique ecosystem. Some of Nansen’s findings on sea ice and the penetration of Atlantic Water into the Arctic Ocean established a benchmark against which we have measured profound changes over the past few decades. In contrast, little was known about the Arctic Ocean’s ecosystem processes prior to the onset of anthropogenic climate change. Nansen’s successes, which paved the way for subsequent research, were gained in part from Indigenous Greenlanders who taught him how to survive in this harsh environment.
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DatasetCTD cast data from 45 R/V Alpha Helix and R/V Wecoma Long-Term Observation Program (LTOP) cruises to the Coastal Gulf of Alaska from 1997-2004 as part of the U.S. GLOBEC program (NEP project)(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2019-11-28) Weingartner, Thomas J.CTD cast data from 45 R/V Alpha Helix and R/V Wecoma Long-Term Observation Program (LTOP) cruises to the Coastal Gulf of Alaska from 1997-2004 as part of the U.S. GLOBEC program (NEP project) For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/2470
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DatasetCruise Event Logs from 15 vessels for 116 U.S. GLOBEC cruises from 1997-2004 in the Northeast Pacific and Gulf of Alaska areas (NEP program)(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2019-02-22) Barth, Jack ; Boldt, Jennifer L ; Brodeur, Richard D ; Cokelet, Edward D. ; Cowles, Timothy ; Danielson, Seth L. ; Emmett, Robert L ; Farley, Edward V. ; Fleischbein, Jane ; Haldorson, Lewis J ; Hopcroft, Russell R. ; Huyer, Adriana ; Janout, Markus A. ; Kachel, Nancy ; Kondzela, Chris ; Moss, Jamal Hasan ; Musgrave, Dave ; Napp, Jeffrey ; Noskov, Jackie Popp ; Peterson, William T. ; Piccolo, Jack ; Royer, Thomas C. ; Smith, Robert ; Stockwell, Dean A. ; Strom, Suzanne ; Thornton, Sarah ; Tynan, Cynthia ; Weingartner, Thomas J. ; Coyle, Kenneth O ; Keister, Julie E. ; Sherr, EvelynCruise Event Logs from 15 vessels for 116 U.S. GLOBEC cruises from 1997-2004 in the Northeast Pacific and Gulf of Alaska areas For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/2341