Articles | Volume 14, issue 3
https://doi.org/10.5194/os-14-503-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/os-14-503-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
| 
22 Jun 2018
Research article | Highlight paper |
| 22 Jun 2018
| 22 Jun 2018
Acoustic mapping of mixed layer depth
Christian Stranne
CORRESPONDING AUTHOR
Department of Geological Sciences, Stockholm University, Stockholm,
Sweden
Bolin Center for Climate Research, Stockholm University, Stockholm,
Sweden
Larry Mayer
Center for Coastal and Ocean Mapping, University of New Hampshire,
Durham, New Hampshire, USA
Martin Jakobsson
Department of Geological Sciences, Stockholm University, Stockholm,
Sweden
Bolin Center for Climate Research, Stockholm University, Stockholm,
Sweden
Elizabeth Weidner
Center for Coastal and Ocean Mapping, University of New Hampshire,
Durham, New Hampshire, USA
Kevin Jerram
Center for Coastal and Ocean Mapping, University of New Hampshire,
Durham, New Hampshire, USA
Thomas C. Weber
Center for Coastal and Ocean Mapping, University of New Hampshire,
Durham, New Hampshire, USA
Leif G. Anderson
Department of Marine Sciences, University of Gothenburg, Gothenburg,
40530, Sweden
Johan Nilsson
Bolin Center for Climate Research, Stockholm University, Stockholm,
Sweden
Department of Meteorology, Stockholm University, Stockholm, Sweden
Göran Björk
Department of Marine Sciences, University of Gothenburg, Gothenburg,
40530, Sweden
Katarina Gårdfeldt
Department of Chemistry and Chemical Engineering, Chalmers University
of Technology, Göteborg, Sweden
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Johan Nilsson, Eef van Dongen, Martin Jakobsson, Matt O'Regan, and Christian Stranne
The Cryosphere, 17, 2455–2476, https://doi.org/10.5194/tc-17-2455-2023, https://doi.org/10.5194/tc-17-2455-2023, 2023
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Gabriel West, Darrell S. Kaufman, Martin Jakobsson, and Matt O'Regan
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Jaclyn Clement Kinney, Karen M. Assmann, Wieslaw Maslowski, Göran Björk, Martin Jakobsson, Sara Jutterström, Younjoo J. Lee, Robert Osinski, Igor Semiletov, Adam Ulfsbo, Irene Wåhlström, and Leif G. Anderson
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Colin Ware, Larry Mayer, Paul Johnson, Martin Jakobsson, and Vicki Ferrini
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Clim. Past Discuss., https://doi.org/10.5194/cp-2020-38, https://doi.org/10.5194/cp-2020-38, 2020
Manuscript not accepted for further review
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Whether an ice sheet once grew over Northeast Siberia-Beringia has been debated for decades. By comparing climate modelling with paleoclimate and glacial records from around the North Pacific, this study shows that the Laurentide-Eurasia-only ice sheet configuration fails in explaining these records, while a scenario involving the ice sheet over Northeast Siberia-Beringia succeeds. It highlights the complexity in glacial climates and urges new investigations across Northeast Siberia-Beringia.
Kelly A. Hogan, Martin Jakobsson, Larry Mayer, Brendan T. Reilly, Anne E. Jennings, Joseph S. Stoner, Tove Nielsen, Katrine J. Andresen, Egon Nørmark, Katrien A. Heirman, Elina Kamla, Kevin Jerram, Christian Stranne, and Alan Mix
The Cryosphere, 14, 261–286, https://doi.org/10.5194/tc-14-261-2020, https://doi.org/10.5194/tc-14-261-2020, 2020
Short summary
Short summary
Glacial sediments in fjords hold a key record of environmental and ice dynamic changes during ice retreat. Here we use a comprehensive geophysical survey from the Petermann Fjord system in NW Greenland to map these sediments, identify depositional processes and calculate glacial erosion rates for the retreating palaeo-Petermann ice stream. Ice streaming is the dominant control on glacial erosion rates which vary by an order of magnitude during deglaciation and are in line with modern rates.
Martin Jakobsson, Matt O'Regan, Carl-Magnus Mörth, Christian Stranne, Elizabeth Weidner, Jim Hansson, Richard Gyllencreutz, Christoph Humborg, Tina Elfwing, Alf Norkko, Joanna Norkko, Björn Nilsson, and Arne Sjöström
Earth Surf. Dynam., 8, 1–15, https://doi.org/10.5194/esurf-8-1-2020, https://doi.org/10.5194/esurf-8-1-2020, 2020
Short summary
Short summary
We studied coastal sea floor terraces in parts of the Baltic Sea using various types of sonar data, sediment cores, and video. Terraces (~1 m high, > 100 m long) are widespread in depths < 15 m and are formed in glacial clay. Our study supports an origin from groundwater flow through silty layers, undermining overlying layers when discharged at the sea floor. Submarine groundwater discharge like this may be a significant source of freshwater to the Baltic Sea that needs to be studied further.
Christian Stranne, Matt O'Regan, Martin Jakobsson, Volker Brüchert, and Marcelo Ketzer
Solid Earth, 10, 1541–1554, https://doi.org/10.5194/se-10-1541-2019, https://doi.org/10.5194/se-10-1541-2019, 2019
Martin Jakobsson, Christian Stranne, Matt O'Regan, Sarah L. Greenwood, Bo Gustafsson, Christoph Humborg, and Elizabeth Weidner
Ocean Sci., 15, 905–924, https://doi.org/10.5194/os-15-905-2019, https://doi.org/10.5194/os-15-905-2019, 2019
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The bottom topography of the Baltic Sea is analysed using the digital depth model from the European Marine Observation and Data Network (EMODnet) published in 2018. Analyses include depth distribution vs. area and seafloor depth variation on a kilometre scale. The limits for the Baltic Sea and analysed sub-basins are from HELCOM. EMODnet is compared with the previously most widely used depth model and the area of deep water exchange between the Bothnian Sea and the Northern Baltic Proper.
Birgit Wild, Natalia Shakhova, Oleg Dudarev, Alexey Ruban, Denis Kosmach, Vladimir Tumskoy, Tommaso Tesi, Hanna Joß, Helena Alexanderson, Martin Jakobsson, Alexey Mazurov, Igor Semiletov, and Örjan Gustafsson
The Cryosphere Discuss., https://doi.org/10.5194/tc-2018-229, https://doi.org/10.5194/tc-2018-229, 2018
Revised manuscript not accepted
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Revised manuscript not accepted
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Our study challenges the widely accepted idea that the Laurentide-Eurasian ice sheets gradually extended across North America and Northwest Eurasia, and suggests the growth of the NH ice sheets is much more complicated. We find climate feedbacks regulate the distribution of the NH ice sheets, producing swings between two distinct ice sheet configurations: the Laurentide-Eurasian and a circum-Arctic configuration, where large ice sheets existed over Northeast Siberia and the Canadian Rockies.
David K. Hutchinson, Agatha M. de Boer, Helen K. Coxall, Rodrigo Caballero, Johan Nilsson, and Michiel Baatsen
Clim. Past, 14, 789–810, https://doi.org/10.5194/cp-14-789-2018, https://doi.org/10.5194/cp-14-789-2018, 2018
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The Eocene--Oligocene transition was a major cooling event 34 million years ago. Climate model studies of this transition have used low ocean resolution or topography that roughly approximates the time period. We present a new climate model simulation of the late Eocene, with higher ocean resolution and topography which is accurately designed for this time period. These features improve the ocean circulation and gateways which are thought to be important for this climate transition.
Göran Björk, Martin Jakobsson, Karen Assmann, Leif G. Andersson, Johan Nilsson, Christian Stranne, and Larry Mayer
Ocean Sci., 14, 1–13, https://doi.org/10.5194/os-14-1-2018, https://doi.org/10.5194/os-14-1-2018, 2018
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This study presents detailed bathymetric data along with hydrographic data at two deep passages across the Lomonosov Ridge in the Arctic Ocean. The southern channel is relatively smooth with a sill depth close to 1700 m. Hydrographic data reveals an eastward flow in the southern part and opposite in the northern part. The northern passage is characterized by a narrow and steep ridge with a sill depth of 1470 m. Here, water exchange appears to occur in well-defined but irregular vertical layers.
Laura Gemery, Thomas M. Cronin, Robert K. Poirier, Christof Pearce, Natalia Barrientos, Matt O'Regan, Carina Johansson, Andrey Koshurnikov, and Martin Jakobsson
Clim. Past, 13, 1473–1489, https://doi.org/10.5194/cp-13-1473-2017, https://doi.org/10.5194/cp-13-1473-2017, 2017
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Continuous, highly abundant and well-preserved fossil ostracodes were studied from radiocarbon-dated sediment cores collected on the Lomonosov Ridge (Arctic Ocean) that indicate varying oceanographic conditions during the last ~50 kyr. Ostracode assemblages from cores taken during the SWERUS-C3 2014 Expedition, Leg 2, reflect paleoenvironmental changes during glacial, deglacial, and interglacial transitions, including changes in sea-ice cover and Atlantic Water inflow into the Eurasian Basin.
Matt O'Regan, Jan Backman, Natalia Barrientos, Thomas M. Cronin, Laura Gemery, Nina Kirchner, Larry A. Mayer, Johan Nilsson, Riko Noormets, Christof Pearce, Igor Semiletov, Christian Stranne, and Martin Jakobsson
Clim. Past, 13, 1269–1284, https://doi.org/10.5194/cp-13-1269-2017, https://doi.org/10.5194/cp-13-1269-2017, 2017
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Past glacial activity on the East Siberian continental margin is poorly known, partly due to the lack of geomorphological evidence. Here we present geophysical mapping and sediment coring data from the East Siberian shelf and slope revealing the presence of a glacially excavated cross-shelf trough reaching to the continental shelf edge north of the De Long Islands. The data provide direct evidence for extensive glacial activity on the Siberian shelf that predates the Last Glacial Maximum.
Thomas M. Cronin, Matt O'Regan, Christof Pearce, Laura Gemery, Michael Toomey, Igor Semiletov, and Martin Jakobsson
Clim. Past, 13, 1097–1110, https://doi.org/10.5194/cp-13-1097-2017, https://doi.org/10.5194/cp-13-1097-2017, 2017
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Global sea level rise during the last deglacial flooded the Siberian continental shelf in the Arctic Ocean. Sediment cores, radiocarbon dating, and microfossils show that the regional sea level in the Arctic rose rapidly from about 12 500 to 10 700 years ago. Regional sea level history on the Siberian shelf differs from the global deglacial sea level rise perhaps due to regional vertical adjustment resulting from the growth and decay of ice sheets.
Martin Jakobsson, Christof Pearce, Thomas M. Cronin, Jan Backman, Leif G. Anderson, Natalia Barrientos, Göran Björk, Helen Coxall, Agatha de Boer, Larry A. Mayer, Carl-Magnus Mörth, Johan Nilsson, Jayne E. Rattray, Christian Stranne, Igor Semiletov, and Matt O'Regan
Clim. Past, 13, 991–1005, https://doi.org/10.5194/cp-13-991-2017, https://doi.org/10.5194/cp-13-991-2017, 2017
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The Arctic and Pacific oceans are connected by the presently ~53 m deep Bering Strait. During the last glacial period when the sea level was lower than today, the Bering Strait was exposed. Humans and animals could then migrate between Asia and North America across the formed land bridge. From analyses of sediment cores and geophysical mapping data from Herald Canyon north of the Bering Strait, we show that the land bridge was flooded about 11 000 years ago.
Johan Nilsson, Martin Jakobsson, Chris Borstad, Nina Kirchner, Göran Björk, Raymond T. Pierrehumbert, and Christian Stranne
The Cryosphere, 11, 1745–1765, https://doi.org/10.5194/tc-11-1745-2017, https://doi.org/10.5194/tc-11-1745-2017, 2017
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Recent data suggest that a 1 km thick ice shelf extended over the glacial Arctic Ocean during MIS 6, about 140 000 years ago. Here, we theoretically analyse the development and equilibrium features of such an ice shelf. The ice shelf was effectively dammed by the Fram Strait and the mean ice-shelf thickness was controlled primarily by the horizontally integrated mass balance. Our results can aid in resolving some outstanding questions of the state of the glacial Arctic Ocean.
Clint M. Miller, Gerald R. Dickens, Martin Jakobsson, Carina Johansson, Andrey Koshurnikov, Matt O'Regan, Francesco Muschitiello, Christian Stranne, and Carl-Magnus Mörth
Biogeosciences, 14, 2929–2953, https://doi.org/10.5194/bg-14-2929-2017, https://doi.org/10.5194/bg-14-2929-2017, 2017
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Continental slopes north of the East Siberian Sea are assumed to hold large amounts of methane. We present pore water chemistry from the 2014 SWERUS-C3 expedition. These are among the first results generated from this vast climatically sensitive region, and they imply that abundant methane, including gas hydrates, do not characterize the East Siberian Sea slope or rise. This contradicts previous modeling and discussions, which due to the lack of data are almost entirely based assumption.
Leif G. Anderson, Göran Björk, Ola Holby, Sara Jutterström, Carl Magnus Mörth, Matt O'Regan, Christof Pearce, Igor Semiletov, Christian Stranne, Tim Stöven, Toste Tanhua, Adam Ulfsbo, and Martin Jakobsson
Ocean Sci., 13, 349–363, https://doi.org/10.5194/os-13-349-2017, https://doi.org/10.5194/os-13-349-2017, 2017
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We use data collected in 2014 to show that the outflow of nutrient-rich water occurs much further to the west than has been reported in the past. We suggest that this is due to much less summer sea-ice coverage in the northwestern East Siberian Sea than in the past decades. Further, our data support a more complicated flow pattern in the region where the Mendeleev Ridge reaches the shelf compared to the general cyclonic circulation within the individual basins as suggested historically.
Christof Pearce, Aron Varhelyi, Stefan Wastegård, Francesco Muschitiello, Natalia Barrientos, Matt O'Regan, Thomas M. Cronin, Laura Gemery, Igor Semiletov, Jan Backman, and Martin Jakobsson
Clim. Past, 13, 303–316, https://doi.org/10.5194/cp-13-303-2017, https://doi.org/10.5194/cp-13-303-2017, 2017
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The eruption of the Alaskan Aniakchak volcano of 3.6 thousand years ago was one of the largest Holocene eruptions worldwide. The resulting ash is found in several Alaskan sites and as far as Newfoundland and Greenland. In this study, we found ash from the Aniakchak eruption in a marine sediment core from the western Chukchi Sea in the Arctic Ocean. Combined with radiocarbon dates on mollusks, the volcanic age marker is used to calculate the marine radiocarbon reservoir age at that time.
Erik Gustafsson, Christoph Humborg, Göran Björk, Christian Stranne, Leif G. Anderson, Marc C. Geibel, Carl-Magnus Mörth, Marcus Sundbom, Igor P. Semiletov, Brett F. Thornton, and Bo G. Gustafsson
Biogeosciences Discuss., https://doi.org/10.5194/bg-2017-115, https://doi.org/10.5194/bg-2017-115, 2017
Preprint withdrawn
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In this study we quantify key carbon cycling processes on the East Siberian Arctic Shelf. A specific aim is to determine the pathways of terrestrial organic carbon (OC) supplied by rivers and coastline erosion – and particularly to what extent degradation of terrestrial OC contributes to air-sea CO2 exchange. We estimate that the shelf is a weak CO2 sink, although this sink is considerably reduced mainly by degradation of eroded OC and to a lesser extent by degradation of riverine OC.
Ingvar Wängberg, Michelle G. Nerentorp Mastromonaco, John Munthe, and Katarina Gårdfeldt
Atmos. Chem. Phys., 16, 13379–13387, https://doi.org/10.5194/acp-16-13379-2016, https://doi.org/10.5194/acp-16-13379-2016, 2016
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Within the EU-funded project, Global Mercury Observation System (GMOS) airborne mercury has been monitored at the background Råö measurement site on the western coast of Sweden from May 2012 to the end of May 2015, the following mercury species/fractions were measured: gaseous elemental mercury (GEM), particulate bound mercury (PBM) and gaseous oxidised mercury (GOM). Evidence that a significant part of the GOM measured at the Råö site has been formed in the free tropospheric air is presented.
Hélène Angot, Ashu Dastoor, Francesco De Simone, Katarina Gårdfeldt, Christian N. Gencarelli, Ian M. Hedgecock, Sarka Langer, Olivier Magand, Michelle N. Mastromonaco, Claus Nordstrøm, Katrine A. Pfaffhuber, Nicola Pirrone, Andrei Ryjkov, Noelle E. Selin, Henrik Skov, Shaojie Song, Francesca Sprovieri, Alexandra Steffen, Kenjiro Toyota, Oleg Travnikov, Xin Yang, and Aurélien Dommergue
Atmos. Chem. Phys., 16, 10735–10763, https://doi.org/10.5194/acp-16-10735-2016, https://doi.org/10.5194/acp-16-10735-2016, 2016
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This is a synthesis of the atmospheric mercury (Hg) monitoring data available in recent years (2011–2015) in the Arctic and in Antarctica along with a comparison of these observations with numerical simulations using four cutting-edge global models. Based on this comparison, we discuss whether the processes that affect atmospheric Hg seasonality and interannual variability are appropriately represented in the models, and identify remaining research gaps.
C. Heinze, S. Meyer, N. Goris, L. Anderson, R. Steinfeldt, N. Chang, C. Le Quéré, and D. C. E. Bakker
Earth Syst. Dynam., 6, 327–358, https://doi.org/10.5194/esd-6-327-2015, https://doi.org/10.5194/esd-6-327-2015, 2015
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Rapidly rising atmospheric CO2 concentrations caused by human actions over the past 250 years have raised cause for concern that changes in Earth’s climate system may progress at a much faster pace and larger extent than during the past 20,000 years. Questions that yet need to be answered are what the carbon uptake kinetics of the oceans will be in the future and how the increase in oceanic carbon inventory will affect its ecosystems. Major future ocean carbon research challenges are discussed.
M. Löfverström, R. Caballero, J. Nilsson, and J. Kleman
Clim. Past, 10, 1453–1471, https://doi.org/10.5194/cp-10-1453-2014, https://doi.org/10.5194/cp-10-1453-2014, 2014
M. Berger, J. Brandefelt, and J. Nilsson
Clim. Past, 9, 969–982, https://doi.org/10.5194/cp-9-969-2013, https://doi.org/10.5194/cp-9-969-2013, 2013
F. O. Nitsche, K. Gohl, R. D. Larter, C.-D. Hillenbrand, G. Kuhn, J. A. Smith, S. Jacobs, J. B. Anderson, and M. Jakobsson
The Cryosphere, 7, 249–262, https://doi.org/10.5194/tc-7-249-2013, https://doi.org/10.5194/tc-7-249-2013, 2013
Related subject area
Approach: Remote Sensing | Depth range: Mixed Layer | Geographical range: All Geographic Regions | Phenomena: Temperature, Salinity and Density Fields
Retrieving the availability of light in the ocean utilising spectral signatures of vibrational Raman scattering in hyper-spectral satellite measurements
T. Dinter, V. V. Rozanov, J. P. Burrows, and A. Bracher
Ocean Sci., 11, 373–389, https://doi.org/10.5194/os-11-373-2015, https://doi.org/10.5194/os-11-373-2015, 2015
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Short summary
The ocean surface mixed layer depth (MLD) is an important parameter within several research disciplines, as variations in the MLD influence air–sea CO2 exchange and ocean primary production. A new method is presented in which acoustic mapping of the MLD is done remotely by means of echo sounders. This method allows for observations of high-frequency variability in the MLD, as horizontal and temporal resolutions can be increased by orders of magnitude compared to traditional in situ measurements.
The ocean surface mixed layer depth (MLD) is an important parameter within several research...
