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Author Morey, S. ; Wienders, N. ; Dukhovskoy, D. ; Bourassa, M.
Title Measurement Characteristics of Near-Surface Currents from Ultra-Thin Drifters, Drogued Drifters, and HF Radar Type $loc['typeJournal Article']
Year 2018 Publication Remote Sensing Abbreviated Journal Remote Sensing
Volume 10
Issue 10
Pages 1633
Keywords surface drifters ; surface currents ; HF Radar
Abstract Concurrent measurements by satellite tracked drifters of different hull and drogue configurations and coastal high-frequency radar reveal substantial differences in estimates of the near-surface velocity. These measurements are important for understanding and predicting material transport on the ocean surface as well as the vertical structure of the near-surface currents. These near-surface current observations were obtained during a field experiment in the northern Gulf of Mexico intended to test a new ultra-thin drifter design. During the experiment, thirty small cylindrical drifters with 5 cm height, twenty-eight similar drifters with 10 cm hull height, and fourteen drifters with 91 cm tall drogues centered at 100 cm depth were deployed within the footprint of coastal High-Frequency (HF) radar. Comparison of collocated velocity measurements reveals systematic differences in surface velocity estimates obtained from the different measurement techniques, as well as provides information on properties of the drifter behavior and near-surface shear. Results show that the HF radar velocity estimates had magnitudes significantly lower than the 5 cm and 10 cm drifter velocity of approximately 45% and 35%, respectively. The HF radar velocity magnitudes were similar to the drogued drifter velocity. Analysis of wave directional spectra measurements reveals that surface Stokes drift accounts for much of the velocity difference between the drogued drifters and the thin surface drifters except during times of wave breaking.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2072-4292
ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ rl18 @
Serial 987
Permanent link to this record
Author Morey, S. ; Wienders, N. ; Dukhovskoy, D. ; Bourassa, M.
Title Measurement Characteristics of Near-Surface Currents from Ultra-Thin Drifters, Drogued Drifters, and HF Radar Type $loc['typeJournal Article']
Year 2018 Publication Remote Sensing Abbreviated Journal Remote Sensing
Volume 10
Issue 10
Pages 1633
Keywords surface drifters ; surface currents ; HF Radar ; STOKES DRIFT ; SEA-SURFACE ; WAVES ; BREAKING ; VALIDATION ; TRANSPORT
Abstract Concurrent measurements by satellite tracked drifters of different hull and drogue configurations and coastal high-frequency radar reveal substantial differences in estimates of the near-surface velocity. These measurements are important for understanding and predicting material transport on the ocean surface as well as the vertical structure of the near-surface currents. These near-surface current observations were obtained during a field experiment in the northern Gulf of Mexico intended to test a new ultra-thin drifter design. During the experiment, thirty small cylindrical drifters with 5 cm height, twenty-eight similar drifters with 10 cm hull height, and fourteen drifters with 91 cm tall drogues centered at 100 cm depth were deployed within the footprint of coastal High-Frequency (HF) radar. Comparison of collocated velocity measurements reveals systematic differences in surface velocity estimates obtained from the different measurement techniques, as well as provides information on properties of the drifter behavior and near-surface shear. Results show that the HF radar velocity estimates had magnitudes significantly lower than the 5 cm and 10 cm drifter velocity of approximately 45% and 35%, respectively. The HF radar velocity magnitudes were similar to the drogued drifter velocity. Analysis of wave directional spectra measurements reveals that surface Stokes drift accounts for much of the velocity difference between the drogued drifters and the thin surface drifters except during times of wave breaking.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2072-4292
ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ rl18 @
Serial 985
Permanent link to this record
Author Harris, R. ; Pollman, C. ; Landing, W. ; Evans, D. ; Axelrad, D. ; Hutchinson, D. ; Morey, S.L. ; Rumbold, D. ; Dukhovskoy, D. ; Adams, D.H. ; Vijayaraghavan, K. ; Holmes, C. ; Atkinson, R.D. ; Myers, T. ; Sunderland, E.
Title Mercury in the Gulf of Mexico: sources to receptors Type $loc['typeJournal Article']
Year 2012 Publication Environmental Research Abbreviated Journal Environ Res
Volume 119
Issue Pages 42-52
Keywords Air Pollutants/chemistry ; Animals ; Environmental Exposure ; Food Chain ; Geologic Sediments/chemistry ; Humans ; Mercury/*chemistry/metabolism ; Seawater/*chemistry ; Water Pollutants, Chemical/*chemistry/metabolism
Abstract Gulf of Mexico (Gulf) fisheries account for 41% of the U.S. marine recreational fish catch and 16% of the nation's marine commercial fish landings. Mercury (Hg) concentrations are elevated in some fish species in the Gulf, including king mackerel, sharks, and tilefish. All five Gulf states have fish consumption advisories based on Hg. Per-capita fish consumption in the Gulf region is elevated compared to the U.S. national average, and recreational fishers in the region have a potential for greater MeHg exposure due to higher levels of fish consumption. Atmospheric wet Hg deposition is estimated to be higher in the Gulf region compared to most other areas in the U.S., but the largest source of Hg to the Gulf as a whole is the Atlantic Ocean (>90%) via large flows associated with the Loop Current. Redistribution of atmospheric, Atlantic and terrestrial Hg inputs to the Gulf occurs via large scale water circulation patterns, and further work is needed to refine estimates of the relative importance of these Hg sources in terms of contributing to fish Hg levels in different regions of the Gulf. Measurements are needed to better quantify external loads, in-situ concentrations, and fluxes of total Hg and methylmercury in the water column, sediments, and food web.
Address Reed Harris Environmental Ltd, 180 Forestwood Drive, Oakville, Ontario L6J4E6, Canada. reed@reed-harris.com
Corporate Author Thesis
Publisher Place of Publication Editor
Language English
Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0013-9351
ISBN Medium
Area Expedition Conference
Funding PMID:23098613
Approved $loc['no']
Call Number COAPS @ mfield @
Serial 233
Permanent link to this record
Author Harris, R. ; Pollman, C. ; Hutchinson, D. ; Landing, W. ; Axelrad, D. ; Morey, S.L. ; Dukhovskoy, D. ; Vijayaraghavan, K.
Title A screening model analysis of mercury sources, fate and bioaccumulation in the Gulf of Mexico Type $loc['typeJournal Article']
Year 2012 Publication Environmental Research Abbreviated Journal Environ Res
Volume 119
Issue Pages 53-63
Keywords Animals ; Calibration ; Environmental Exposure ; Fishes/metabolism ; Humans ; Mercury/*chemistry/metabolism ; *Models, Theoretical ; Seawater/*chemistry ; Water Pollutants, Chemical/*chemistry/metabolism
Abstract A mass balance model of mercury (Hg) cycling and bioaccumulation was applied to the Gulf of Mexico (Gulf), coupled with outputs from hydrodynamic and atmospheric Hg deposition models. The dominant overall source of Hg to the Gulf is the Atlantic Ocean. Gulf waters do not mix fully however, resulting in predicted spatial differences in the relative importance of external Hg sources to Hg levels in water, sediments and biota. Direct atmospheric Hg deposition, riverine inputs, and Atlantic inputs were each predicted to be the most important source of Hg to at least one of the modeled regions in the Gulf. While incomplete, mixing of Gulf waters is predicted to be sufficient that fish Hg levels in any given location are affected by Hg entering other regions of the Gulf. This suggests that a Gulf-wide approach is warranted to reduce Hg loading and elevated Hg concentrations currently observed in some fish species. Basic data to characterize Hg concentrations and cycling in the Gulf are lacking but needed to adequately understand the relationship between Hg sources and fish Hg concentrations.
Address Reed Harris Environmental Ltd., 180 Forestwood Drive, Oakville, Ontario L6J4E6, Canada. reed@reed-harris.com
Corporate Author Thesis
Publisher Place of Publication Editor
Language English
Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0013-9351
ISBN Medium
Area Expedition Conference
Funding PMID:23102631
Approved $loc['no']
Call Number COAPS @ mfield @
Serial 234
Permanent link to this record
Author Proshutinsky, A. ; Dukhovskoy, D. ; Timmermans, M.-L. ; Krishfield, R. ; Bamber, J.L.
Title Arctic circulation regimes Type $loc['typeJournal Article']
Year 2015 Publication Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences Abbreviated Journal Philos Trans A Math Phys Eng Sci
Volume 373
Issue 2052
Pages
Keywords arctic climate variability ; circulation regimes ; freshwater and heat content
Abstract Between 1948 and 1996, mean annual environmental parameters in the Arctic experienced a well-pronounced decadal variability with two basic circulation patterns: cyclonic and anticyclonic alternating at 5 to 7 year intervals. During cyclonic regimes, low sea-level atmospheric pressure (SLP) dominated over the Arctic Ocean driving sea ice and the upper ocean counterclockwise; the Arctic atmosphere was relatively warm and humid, and freshwater flux from the Arctic Ocean towards the subarctic seas was intensified. By contrast, during anticylonic circulation regimes, high SLP dominated driving sea ice and the upper ocean clockwise. Meanwhile, the atmosphere was cold and dry and the freshwater flux from the Arctic to the subarctic seas was reduced. Since 1997, however, the Arctic system has been under the influence of an anticyclonic circulation regime (17 years) with a set of environmental parameters that are atypical for this regime. We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from the Arctic Ocean and Greenland impact environmental conditions and interrupt their decadal variability.
Address School of Geographical Sciences, University of Bristol, Bristol, UK
Corporate Author Thesis
Publisher Place of Publication Editor
Language English
Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1364-503X
ISBN Medium
Area Expedition Conference
Funding PMID:26347536; PMCID:PMC4607701
Approved $loc['no']
Call Number COAPS @ mfield @
Serial 109
Permanent link to this record
Author Dukhovskoy, D.S. ; Yashayaev, I. ; Proshutinsky, A. ; Bamber, J.L. ; Bashmachnikov, I.L. ; Chassignet, E.P. ; Lee, C.M. ; Tedstone, A.J.
Title Role of Greenland Freshwater Anomaly in the Recent Freshening of the Subpolar North Atlantic Type $loc['typeJournal Article']
Year 2019 Publication Journal of Geophysical Research: Oceans Abbreviated Journal J. Geophys. Res. Oceans
Volume 124
Issue 5
Pages 3333-3360
Keywords Greenland ice sheet melting ; freshwater anomaly ; subpolar North Atlantic ; subpolar gyre ; passive tracer numerical experiment ; freshwater budget
Abstract The cumulative Greenland freshwater flux anomaly has exceeded 5000 km3 since the 1990s. The volume of this surplus fresh water is expected to cause substantial freshening in the North Atlantic. Analysis of hydrographic observations in the subpolar seas reveal freshening signals in the 2010s. The sources of this freshening are yet to be determined. In this study, the relationship between the surplus Greenland freshwater flux and this freshening is tested by analyzing the propagation of the Greenland freshwater anomaly and its impact on salinity in the subpolar North Atlantic based on observational data and numerical experiments with and without the Greenland runoff. A passive tracer is continuously released during the simulations at freshwater sources along the coast of Greenland to track the Greenland freshwater anomaly. Tracer budget analysis shows that 44% of the volume of the Greenland freshwater anomaly is retained in the subpolar North Atlantic by the end of the simulation. This volume is sufficient to cause strong freshening in the subpolar seas if it stays in the upper 50�100 m. However, in the model the anomaly is mixed down to several hundred meters of the water column resulting in smaller magnitudes of freshening compared to the observations. Therefore, the simulations suggest that the accelerated Greenland melting would not be sufficient to cause the observed freshening in the subpolar seas and other sources of fresh water have contributed to the freshening. Impacts on salinity in the subpolar seas of the freshwater transport through Fram Strait and precipitation are discussed.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2169-9275
ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ user @
Serial 1029
Permanent link to this record
Author Garcia-Pineda, O. ; MacDonald, I. ; Hu, C. ; Svejkovsky, J. ; Hess, M. ; Dukhovskoy, D. ; Morey, S.
Title Detection of Floating Oil Anomalies From the Deepwater Horizon Oil Spill With Synthetic Aperture Radar Type $loc['typeJournal Article']
Year 2013 Publication Oceanography Abbreviated Journal oceanog
Volume 26
Issue 2
Pages
Keywords
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1042-8275
ISBN Medium
Area Expedition Conference
Funding Deep-C, BOEM
Approved $loc['no']
Call Number COAPS @ mfield @
Serial 213
Permanent link to this record
Author Özgökmen, T. ; Chassignet, E. ; Dawson, C. ; Dukhovskoy, D. ; Jacobs, G. ; Ledwell, J. ; Garcia-Pineda, O. ; MadDonald, I. ; Morey, S. ; Olascoaga, M. ; Poje, A. ; Reed, M. ; Skancke, J.
Title Over What Area Did the Oil and Gas Spread During the 2010 Deepwater Horizon Oil Spill? Type $loc['typeJournal Article']
Year 2016 Publication Oceanography Abbreviated Journal Oceanog
Volume 29
Issue 3
Pages 96-107
Keywords
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1042-8275
ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ mfield @
Serial 87
Permanent link to this record
Author Zheng, Y. ; Bourassa, M. A. ; Dukhovskoy, D. S.
Title Upper-Ocean Processes Controlling the Sea Surface Temperature in the Western Gulf of Mexico Type $loc['typeAbstract']
Year 2018 Publication American Geophysical Union Abbreviated Journal AGU
Volume Fall Meeting
Issue Pages
Keywords 4299 General or miscellaneous, OCEANOGRAPHY: GENERAL
Abstract This study examines the upper-ocean processes controlling the mixed layer temperature in the western Gulf of Mexico (GOM) through estimating the contributing terms in the heat equation, with an emphasis on eddies' role. The major heat contributing terms for the upper GOM were estimated using two ocean reanalysis datasets: an eddy-resolving HYbrid Coordinate Ocean Model (HYCOM) and a Simple Ocean Data Assimilation (SODA). Analysis of net surface heat fluxes from four datasets reveals that the long-term mean net surface heat flux cools the northern GOM and warms the southern GOM. Two regions are focused for analysis: an eddy-rich region where LCEs are energetic, and the southwestern Gulf where eddy activity is relatively weak and the features of near surface temperature differ from the eddy-rich region. An eddy-rich region in the western GOM is defined based on the eddy kinetic energy derived from satellite sea surface heights. The long-term mean horizontal heat advection causes a weak warming over most of the eddy rich region, partly attributed to the flow-temperature configuration that the long-term and seasonally mean flow is nearly parallel to the corresponding mean isotherms. By contrast, the temporal mean vertical heat advection causes a strong warming in the eddy rich region, partly balancing the cooling caused by net surface heat flux. The temporal mean eddy heat flux convergence in the western GOM, whose positive and negative values are not small at some locations, appears heterogeneous in space, resulting in a small term for the western GOM when area averaged. The persistent warm water in the southwestern Gulf is primarily caused by the net warming from net surface heat flux rather than from eddies and heat advection.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ user @
Serial 1007
Permanent link to this record
Author Morrison, T. ; Dukhovskoy, D. S. ; McClean, J. ; Gille, S. T. ; Chassignet, E.
Title Causes of the anomalous heat flux onto the Greenland continental shelf Type $loc['typeAbstract']
Year 2018 Publication American Geophysical Union Abbreviated Journal AGU
Volume Fall Meeting
Issue Pages
Keywords 0726 Ice sheets, CRYOSPHEREDE: 4207 Arctic and Antarctic oceanography, OCEANOGRAPHY: GENERALDE: 4215 Climate and interannual variability, OCEANOGRAPHY: GENERALDE: 4255 Numerical modeling, OCEANOGRAPHY: GENERAL
Abstract On the continental shelf around Greenland, warm-salty Atlantic water at depth fills the deep narrow fjords where Greenland's tidewater glaciers terminate. Changes in the quantity or properties of this water mass starting in the mid 1990s is thought to be largely responsible for increased ocean-driven melting of the Greenland Ice Sheet. Using high-resolution (nominal 0.1-degree) ocean circulation models we cannot accurately resolve small-scale processes on the shelf or within fjords. However, we can assess changes in the flux of heat via Atlantic water onto the continental shelf. To understand the causes of the anomalous heat that has reached the shelf we examine heat content of subtropical gyre water and shifts in the North Atlantic and Atlantic Multidecadal Oscillations.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ user @
Serial 1009
Permanent link to this record
