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Variability in the Location. of the Antarctic Polar Front (90 °
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 102, NO. C13, PAGES 27,825-27,833, DECEMBER 15, !997 Variability in the location.of the Antarctic Polar Front (90ø- 20øW) from satellite sea surface temperature data J. Keith Moore, Mark R. Abbott, and James G. Richman Collegeof Oceanicand AtmosphericSciences, Oregon State University, Corvallis Abstract. The path of the AntarcticPolar Front (PF) is mappedusing satellite sea surfacetemperature data from the NOAA/NASA Pathfinderprogram. The mean path and variabilityof the PF are stronglyinfluenced by bathymetry.Meandering intensity is weaker where the bathymetryis steeplysloped and increasesin areaswhere the bottom is relativelyflat. There is an inverserelationship between meandering intensity and both the width of the front and the changein temperatureacross it. There is a persistent,large separationbetween the surfaceand subsurfaceexpressions of the PF at Ewing Bank on the Falkland Plateau. 1. Introduction of meanderingjets and fronts hasbeen done previouslyfor the PF [Legeckis,1977] and other strongfrontal systems[Hansen TheAntarctic Polar Front (PF) is a strongjet within t•e and Maul, 1970; Olsonet al., 1983; Cornilion, 1986]. Antarctic CircumpolarCurrent (ACG), which flowseastward Satellite altimeter data has shown that there is little zonal continuouslyaround Antarctica [Nowlin and Klinck, 1986].The coherencein the variabilityof the ACC [Fu and Chelton,1984; PF, also known as the Antarctic Convergence,is the location Sandwelland Zhang, 1989; Chelton et al., 1990; Gille, 1994; where Antarctic surfacewaters movingto the north sink rap- Gille and Kelly,1996]. These studies emphasize the importance idly belowSubantarctic waters [Deacon, 1933, 1937].Thus the of local and regionalinstabilities [Chelton et al., 1990;Gille and PF is a regionof elevatedcurrent speeds and stronghorizontal Kelly,1996]. -
Modification and Pathways of Southern Ocean Deep Waters in the Scotia
Deep-Sea Research I 49 (2002) 681–705 Modification and pathways of Southern Ocean Deep Waters in the Scotia Sea Alberto C. Naveira Garabatoa,*, Karen J. Heywooda, David P. Stevensb a School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK b School of Mathematics, University of East Anglia, Norwich NR4 7TJ, UK Received 11 September 2000; received in revised form 11 June 2001; accepted 23 October 2001 Abstract An unprecedented high-quality, quasi-synoptic hydrographic data set collected during the ALBATROSS cruise along the rim of the Scotia Sea is examined to describe the pathways of the deep water masses flowing through the region, and to quantify changes in their properties as they cross the sea. Owing to sparse sampling of the northern and southern boundaries of the basin, the modification and pathways of deep water masses in the Scotia Sea had remained poorly documented despite their global significance. Weddell Sea Deep Water (WSDW) of two distinct types is observed spilling over the South Scotia Ridge to the west and east of the western edge of the Orkney Passage. The colder and fresher type in the west, recently ventilated in the northern Antarctic Peninsula, flows westward to Drake Passage along the southern margin of the Scotia Sea while mixing intensely with eastward-flowing Circumpolar Deep Water (CDW) of the antarctic circumpolar current (ACC). Although a small fraction of the other WSDW type also spreads westward to Drake Passage, the greater part escapes the Scotia Sea eastward through the Georgia Passage and flows into the Malvinas Chasm via a deep gap northeast of South Georgia. -
Chapter 4 Tectonic Reconstructions of the Southernmost Andes and the Scotia Sea During the Opening of the Drake Passage
123 Chapter 4 Tectonic reconstructions of the Southernmost Andes and the Scotia Sea during the opening of the Drake Passage Graeme Eagles Alfred Wegener Institute, Helmholtz Centre for Marine and Polar Research, Bre- merhaven, Germany e-mail: [email protected] Abstract Study of the tectonic development of the Scotia Sea region started with basic lithological and structural studies of outcrop geology in Tierra del Fuego and the Antarctic Peninsula. To 19th and early 20th cen- tury geologists, the results of these studies suggested the presence of a submerged orocline running around the margins of the Scotia Sea. Subse- quent increases in detailed knowledge about the fragmentary outcrop ge- ology from islands distributed around the margins of the Scotia Sea, and later their interpretation in light of the plate tectonic paradigm, led to large modifications in the hypothesis such that by the present day the concept of oroclinal bending in the region persists only in vestigial form. Of the early comparative lithostratigraphic work in the region, only the likenesses be- tween Jurassic—Cretaceous basin floor and fill sequences in South Geor- gia and Tierra del Fuego are regarded as strong enough to be useful in plate kinematic reconstruction by permitting the interpretation of those re- gions’ contiguity in mid-Mesozoic times. Marine and satellite geophysical data sets reveal features of the remaining, submerged, 98% of the Scotia 124 Sea region between the outcrops. These data enable a more detailed and quantitative approach to the region’s plate kinematics. In contrast to long- used interpretations of the outcrop geology, these data do not prescribe the proximity of South Georgia to Tierra del Fuego in any past period. -
In Shackleton's Footsteps
In Shackleton’s Footsteps 20 March – 06 April 2019 | Polar Pioneer About Us Aurora Expeditions embodies the spirit of adventure, travelling to some of the most wild and adventure and discovery. Our highly experienced expedition team of naturalists, historians and remote places on our planet. With over 27 years’ experience, our small group voyages allow for destination specialists are passionate and knowledgeable – they are the secret to a fulfilling a truly intimate experience with nature. and successful voyage. Our expeditions push the boundaries with flexible and innovative itineraries, exciting wildlife Whilst we are dedicated to providing a ‘trip of a lifetime’, we are also deeply committed to experiences and fascinating lectures. You’ll share your adventure with a group of like-minded education and preservation of the environment. Our aim is to travel respectfully, creating souls in a relaxed, casual atmosphere while making the most of every opportunity for lifelong ambassadors for the protection of our destinations. DAY 1 | Wednesday 20 March 2019 Ushuaia, Beagle Channel Position: 21:50 hours Course: 84° Wind Speed: 5 knots Barometer: 1007.9 hPa & falling Latitude: 54°55’ S Speed: 9.4 knots Wind Direction: E Air Temp: 11°C Longitude: 67°26’ W Sea Temp: 9°C Finally, we were here, in Ushuaia aboard a sturdy ice-strengthened vessel. At the wharf Gary Our Argentinian pilot climbed aboard and at 1900 we cast off lines and eased away from the and Robyn ticked off names, nabbed our passports and sent us off to Kathrine and Scott for a wharf. What a feeling! The thriving city of Ushuaia receded as we motored eastward down the quick photo before boarding Polar Pioneer. -
West Antarctic Ice Sheet Retreat in the Amundsen Sea Driven by Decadal Oceanic Variability
1 West Antarctic Ice Sheet retreat in the Amundsen Sea driven by decadal oceanic variability 2 Adrian Jenkins1*, Deb Shoosmith1, Pierre Dutrieux2, Stan Jacobs2, Tae Wan Kim3, Sang Hoon Lee3, Ho 3 Kyung Ha4 & Sharon Stammerjohn5 4 1British Antarctic Survey, Natural Environment Research Council, Cambridge CB3 0ET, U.K. 5 2Lamont‐Doherty Earth Observatory of Columbia University, Palisades, NY 10964, U.S.A. 6 3Korea Polar Research Institute, Incheon 406‐840, Korea. 7 4Department of Ocean Sciences, Inha University, Incheon 22212, Korea. 8 5Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, U.S.A. 9 10 Mass loss from the Amundsen Sea sector of the West Antarctic Ice Sheet has increased in recent 11 decades, suggestive of sustained ocean forcing or ongoing, possibly unstable response to a past 12 climate anomaly. Lengthening satellite records appear incompatible with either process, 13 however, revealing both periodic hiatuses in acceleration and intermittent episodes of thinning. 14 Here we use ocean temperature, salinity, dissolved‐oxygen and current measurements taken from 15 2000‐2016 near Dotson Ice Shelf to determine temporal changes in net basal melting. A decadal 16 cycle dominates the ocean record, with melt changing by a factor of ~4 between cool and warm 17 extremes via a non‐linear relationship with ocean temperature. A warm phase that peaked 18 around 2009 coincided with ice shelf thinning and retreat of the grounding line, which re‐ 19 advanced during a post‐2011 cool phase. Those observations demonstrate how discontinuous ice 20 retreat is linked with ocean variability, and that the strength and timing of decadal extremes is 21 more influential than changes in the longer‐term mean state. -
Hydrography and Phytoplankton Distribution in the Amundsen and Ross Seas
W&M ScholarWorks Dissertations, Theses, and Masters Projects Theses, Dissertations, & Master Projects 2009 Hydrography and Phytoplankton Distribution in the Amundsen and Ross Seas Glaucia M. Fragoso College of William and Mary - Virginia Institute of Marine Science Follow this and additional works at: https://scholarworks.wm.edu/etd Part of the Marine Biology Commons, and the Oceanography Commons Recommended Citation Fragoso, Glaucia M., "Hydrography and Phytoplankton Distribution in the Amundsen and Ross Seas" (2009). Dissertations, Theses, and Masters Projects. Paper 1539617887. https://dx.doi.org/doi:10.25773/v5-kwnk-k208 This Thesis is brought to you for free and open access by the Theses, Dissertations, & Master Projects at W&M ScholarWorks. It has been accepted for inclusion in Dissertations, Theses, and Masters Projects by an authorized administrator of W&M ScholarWorks. For more information, please contact [email protected]. Hydrography and phytoplankton distribution in the Amundsen and Ross Seas A Thesis Presented to The Faculty of the School of Marine Science The College of William and Mary in Virginia In Partial Fulfillment of the Requirements for the Degree of Master of Science by Glaucia M. Fragoso 2009 APPROVAL SHEET This thesis is submitted in partial fulfillment of the requirements for the degree of Master of Science UAA£ a Ck laucia M. Frago Approved by the Committee, November 2009 Walker O. Smith, Ph D. Commitfbe Chairman/Advisor eborah A. BronkfPh.D Deborah K. Steinberg, Ph Kam W. Tang ■ Ph.D. DEDICATION I dedicate this work to my parents, Claudio and Vera Lucia Fragoso, and family for their encouragement, guidance and unconditional love. -
Physical Drivers of Phytoplankton Bloom Initiation in the Southern Ocean's Scotia Sea
UC San Diego UC San Diego Previously Published Works Title Physical Drivers of Phytoplankton Bloom Initiation in the Southern Ocean's Scotia Sea Permalink https://escholarship.org/uc/item/9tz4q3pc Journal JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 124(8) ISSN 2169-9275 Authors Prend, Channing J Gille, Sarah T Talley, Lynne D et al. Publication Date 2019-08-01 DOI 10.1029/2019JC015162 Peer reviewed eScholarship.org Powered by the California Digital Library University of California RESEARCH ARTICLE Physical Drivers of Phytoplankton Bloom Initiation 10.1029/2019JC015162 in the Southern Ocean's Scotia Sea Key Points: Channing J. Prend1 , Sarah T. Gille1 , Lynne D. Talley1 , B. Greg Mitchell1 , • Shallow mixed layers in the Scotia 1 1 Sea support the earliest and largest Isabella Rosso , and Matthew R. Mazloff offshore spring phytoplankton 1 bloom in the Southern Ocean Scripps Institution of Oceanography, La Jolla, CA, USA • About 10% of the water in the bloom region is advected from the Weddell Sea, which helps set the unique Abstract The Scotia Sea is the site of one of the largest spring phytoplankton blooms in the Southern fi strati cation Ocean. Past studies suggest that shelf‐iron inputs are responsible for the high productivity in this region, • Vertical transport associated with a stratified Taylor column may but the physical mechanisms that initiate and sustain the bloom are not well understood. Analysis of enhance productivity by supplying profiling float data from 2002 to 2017 shows that the Scotia Sea has an unusually shallow mixed‐layer depth subsurface iron to the euphotic zone during the transition from winter to spring, allowing the region to support a bloom earlier in the season than elsewhere in the Antarctic Circumpolar Current. -
Chapter 6 Antarctic Oceanography the Region of the World Ocean Bordering on Antarctica Is Unique in Many Respects. First of All
Chapter 6 Antarctic oceanography The region of the world ocean bordering on Antarctica is unique in many respects. First of all, it is the only region where the flow of water can continue all around the globe nearly unhindered and the circulation therefore comes closest to the situation in the atmosphere. Secondly, the permanent thermocline (the interface z = H(x,y) of Figure 3.1) reaches the surface in the Subtropical Convergence (Figure 5.5) and does not extend into the polar regions; temperature differences between the sea surface and the ocean floor close to the continent are below 1°C and generally do not exceed 5°C, i.e. 20% of the difference found in 1 the tropics (Figure 6.1). What this means is that our 1 /2 layer ocean model cannot be applied to the seas around Antarctica. Fig. 6.1. Temperature profiles for different climatic regions near 150°W (Pacific Ocean). (a) tropical (5°S), (b) subtropical (35°S), (c) subpolar (50°S), (d) polar (55°S). The temperature scale is correct for the polar profile; other profiles are shifted successively by 1°C. Note the shallowness of the warm surface layer and the absence of the permanent thermocline in the polar region. Data from Osborne et al. (1991). It may seem strange that having spent five chapters on a discussion of temperate and tropical ocean dynamics, we now begin our regional discussion with a region that does not fit the earlier picture. However, our earlier discussion is not entirely irrelevant; it taught us how to get an idea of a region's dynamics by identifying the important forces and looking at their balance. -
The Age and Origin of the Central Scotia Sea
Geophysical Journal International Geophys. J. Int. (2010) 183, 587–600 doi: 10.1111/j.1365-246X.2010.04781.x The age and origin of the central Scotia Sea Graeme Eagles Department of Earth Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK. E-mail: [email protected] Accepted 2010 August 18. Received 2010 July 6; in original form 2010 May 7 SUMMARY Opening of the Drake Passage gateway between the Pacific and Atlantic oceans has been linked in various ways to Cenozoic climate changes. From the oceanic floor of Drake Passage, the largest of the remaining uncertainties in understanding this opening is in the timing and process of the opening of the central Scotia Sea. All but one of the available constraints on the age of the central Scotia Sea is diagnostic of, or consistent with, a Mesozoic age. Comparison of tectonic and magnetic features on the seafloor with plate kinematic models shows that it is likely to have accreted to a mid-ocean ridge between the South American and Antarctic plates following their separation in Jurassic times. Subsequent regional shallowing may be related GJI Geodynamics and tectonics to subduction-related processes that preceded backarc extension in the East Scotia Sea. The presence of a fragment of Jurassic–Cretaceous ocean floor in the gateway implies that deep water connections through the Scotia Sea basin complex may have been possible since Eocene times when the continental tips of South America and the Antarctic Peninsula first passed each other. Key words: Tectonics and climate interactions; Kinematics of crustal and mantle deforma- tion; Antarctica; South America. -
Origin, Signature and Palaeoclimatic Influence of the Antarctic Circumpolar Current
Earth-Science Reviews 66 (2004) 143–162 www.elsevier.com/locate/earscirev Origin, signature and palaeoclimatic influence of the Antarctic Circumpolar Current P.F. Barkera,*, E. Thomasb,c a 25 Church St., Great Gransden, Sandy, Beds SG19 3AF, UK b Department of Earth and Environmental Sciences, Wesleyan University, Middletown, CT 06457, USA c Center for the Study of Global Change, Department of Geology and Geophysics, Yale University, New Haven, CT 06520-1809, USA Accepted 27 October 2003 Abstract The Antarctic Circumpolar Current (ACC) is today the strongest current in the world’s ocean, with a significant influence on global climate. Its assumed history and influence on palaeoclimate, while almost certainly equally profound, are here called into question. In this paper, we review 30 years of accumulated data, interpretation and speculation about the ACC, deriving mainly from DSDP and ODP drilling in the Southern Ocean. For most of this time, a conventional view of ACC development, signature and influence has held sway among palaeoceanographers and marine geologists. In this view, the ACC began at about 34 Ma, close to the Eocene–Oligocene boundary, the time of onset of significant Antarctic glaciation and the time of creation of a deep-water gap (Tasmanian Seaway) between Australia and Antarctica as the South Tasman Rise separated from North Victoria Land. This is the ‘‘smoking gun’’ of synchroneity. The Southern Ocean sediment record shows a latest Eocene development and subsequent geographic expansion of a siliceous biofacies, its northern limit taken to indicate the palaeo- position of the ACC axis. In addition, the ACC was considered to have caused Antarctic glaciation by isolating the continent within a cold-water annulus, reducing north–south heat transport. -
Patricia L. Yager, Ph.D
Patricia L. Yager, Ph.D. ADDRESS, TELEPHONE Department of Marine Sciences (706) 340-2273 University of Georgia, Athens, Georgia 30602-3636 [email protected] Researcher ID: K-8020-2014 Profile in Google Scholar ORCID: orcid.org/0000-0002-8462-6427 Brazil Lattes: 8808128639645246 EDUCATION 1996 Doctor of Philosophy. Biological Oceanography. School of Oceanography, University of Washington, Seattle, Washington. Major Professor: J. W. Deming. 1988 Master of Science. Marine Geology and Geophysics. School of Oceanography, University of Washington, Seattle, Washington. Major Professor: A. R. M. Nowell. 1985 Bachelor of Science. Geology-Biology. Brown University, Department of Geology, Providence, Rhode Island. Advisor: W. L. Prell. PROFESSIONAL EXPERIENCE 2016– Professor. Department of Marine Sciences, University of Georgia, Athens, Georgia. 2013–16 Visiting Professor. Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil. Science without Borders (Ciência sem Fronteiras). Host: F.L. Thompson. 2012– Affiliate Faculty. Latin American and Caribbean Studies Institute, University of Georgia. 2010– Director. Georgia Initiative for Climate and Society. University of Georgia 2007–16 Associate Professor. Department of Marine Sciences, University of Georgia. 1999– Affiliate Faculty. Institute for Women's Studies (IWS), University of Georgia. 1998–07 Assistant Professor. Department of Marine Sciences, University of Georgia. 1996–98 Assistant Professor. Department of Oceanography, Florida State University. 1996 Postdoctoral Fellow. University Corporation for Atmospheric Research (UCAR) Postdoctoral Program in Ocean Modeling. Advisor: Dr. R. G. Wiegert. 1991–96 Graduate Fellow. Department of Energy, Graduate Fellowship for Global Change. University of Washington, Seattle, Washington. Major professor: Dr. J. W. Deming. 1989–91 Research Scientist (Oceanographer I, II). University of Washington, Seattle, Washington. -
The Indian Ocean and the Himalayas : a Geological Interpretation
The Indian Ocean and the Himalayas : a geological interpretation Autor(en): Gansser, Augusto Objekttyp: Article Zeitschrift: Eclogae Geologicae Helvetiae Band (Jahr): 59 (1966) Heft 2 PDF erstellt am: 11.10.2021 Persistenter Link: http://doi.org/10.5169/seals-163396 Nutzungsbedingungen Die ETH-Bibliothek ist Anbieterin der digitalisierten Zeitschriften. Sie besitzt keine Urheberrechte an den Inhalten der Zeitschriften. Die Rechte liegen in der Regel bei den Herausgebern. Die auf der Plattform e-periodica veröffentlichten Dokumente stehen für nicht-kommerzielle Zwecke in Lehre und Forschung sowie für die private Nutzung frei zur Verfügung. Einzelne Dateien oder Ausdrucke aus diesem Angebot können zusammen mit diesen Nutzungsbedingungen und den korrekten Herkunftsbezeichnungen weitergegeben werden. Das Veröffentlichen von Bildern in Print- und Online-Publikationen ist nur mit vorheriger Genehmigung der Rechteinhaber erlaubt. Die systematische Speicherung von Teilen des elektronischen Angebots auf anderen Servern bedarf ebenfalls des schriftlichen Einverständnisses der Rechteinhaber. Haftungsausschluss Alle Angaben erfolgen ohne Gewähr für Vollständigkeit oder Richtigkeit. Es wird keine Haftung übernommen für Schäden durch die Verwendung von Informationen aus diesem Online-Angebot oder durch das Fehlen von Informationen. Dies gilt auch für Inhalte Dritter, die über dieses Angebot zugänglich sind. Ein Dienst der ETH-Bibliothek ETH Zürich, Rämistrasse 101, 8092 Zürich, Schweiz, www.library.ethz.ch http://www.e-periodica.ch The Indian Ocean and the Himalayas A Geological Interpretation by Augusto Gansser (Zürich)1) with 4 figures in the text and 2 plates (I and II) ABSTRACT The recently discovered lineaments of the Indian Ocean indicate a northwards shift of the Indian Shield which is directly responsible for the Himalayan Orogeny.