DOCSLIB.ORG

Polynya Formation in Hudson Bay During the Winter Period By

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Polynya Formation in Hudson Bay During the Winter Period By Polynya Formation in Hudson Bay During the Winter Period by Geoffrey Gunn A Thesis submitted to the Faculty of Graduate Studies of The University of Manitoba in partial fulfilment of the requirements of the degree of MASTER OF SCIENCE Department of Environment and Geography University of Manitoba Winnipeg Copyright ©2014 by Geoffrey Gunn ABSTRACT Previous understanding of the winter ice regime in Hudson Bay was limited. This investigation demonstrates the existence of a large coastal polynya in northwestern Hudson Bay. Measuring approximately 600 km long by 60 km wide, this polynya is typically opened and maintained by surface winds for periods of one to five days. Closing mechanisms result from decline in wind maintenance and apparent thermodynamic ice formation. Open water is present on the northwest coast at some size for up to 70% of the winter between ice formation and breakup. Observation of this open water during the period of the winter ice pack indicates that the ‘ice factory’, modelled previously, in northwest Hudson Bay exists. This furthers understanding of the freshwater budgets, stratification, and atmosphere-ocean interactions while presenting new questions about climate change and the future of the Hudson Bay physical system. i ACKNOWLEDGEMENTS Thanks to the support, knowledge, and enthusiasm of my supervisor Dr. David Barber and committee members Dr. Jens Ehn, Mr. Pierre Larouche, and Dr. Greg McCullough. The thesis herein would not have been possible without the expertise and passion of the members of the Centre for Earth Observation Science at the University of Manitoba: the passion for Arctic science and discovery is infectious. Financial support for this was provided by ArcticNET – a Network of Centres of Excellence; the Natural Science and Engineering Research Council (NSERC); the Northern Scientific Training Program; and Manitoba Hydro. Special thanks to my family from whom I gained respect for science and nature. Especially thank you to my new wife Mallory, who has supported me the whole time (and told me to relax!). ii DEDICATION This thesis is built upon a foundation laid by the late Dr. Klaus Hochheim. the insight and mentorship he provided is hopefully apparent in this document. Sumus nanos gigantum humeris insidentes iii CONTENTS Abstract ................................................................................................................... i Acknowledgements ................................................................................................ii Dedication .............................................................................................................. iii List of Tables ............................................................................................................... v List of Figures ............................................................................................................. vi 1 Introduction ...................................................................................................... 1 1.1 Research Objectives ...................................................................................... 2 1.2 Thesis Structure ............................................................................................ 2 2 Literature Review ............................................................................................. 3 2.1 Sea Ice and Oceans ....................................................................................... 3 2.1.1 Formation ............................................................................................. 3 2.1.2 Motion .................................................................................................. 6 2.1.3 Decay .................................................................................................... 8 2.1.4 Fast Ice.................................................................................................. 9 2.1.5 Polynyas and Leads .............................................................................. 9 2.2 Remote Sensing of Sea Ice .......................................................................... 13 2.2.1 Passive Microwave Radiometry and Sea Ice ...................................... 14 2.2.2 Spatial Measurement of Sea Ice ........................................................ 16 2.2.3 Polynya Detection .............................................................................. 19 2.3 Hudson Bay Marine Complex ..................................................................... 22 2.3.1 Physical Oceanography ...................................................................... 22 2.3.2 Sea Ice Regime ................................................................................... 24 2.3.3 Atmospheric Influences ..................................................................... 27 2.3.4 Northwestern Hudson Bay Polynya ................................................... 28 3 Methods .......................................................................................................... 31 3.1 Study Area ................................................................................................... 31 3.2 Data Sources ............................................................................................... 33 3.2.1 Passive Microwave Orbital Data ........................................................ 33 3.2.2 Operational Ice Charts ....................................................................... 33 3.2.3 Optical Orbital Data ............................................................................ 34 3.2.4 Oceanographic Data ........................................................................... 35 3.2.5 Atmospheric Data .............................................................................. 36 3.3 Analysis ....................................................................................................... 36 3.3.1 Determination of Consolidated Period .............................................. 36 3.3.2 Spatial and Temporal Analyses of Sea Ice and Atmosphere .............. 37 4 Results and Discussion .................................................................................... 39 4.1 Results ......................................................................................................... 39 iv 4.1.1 Seasonal Study Periods ...................................................................... 39 4.1.2 Northwest Hudson Bay Polynya Morphology .................................... 40 4.1.3 Spatial and Temporal Variability of the Polynya ................................ 45 4.1.4 Atmospheric Forcing Mechanisms ..................................................... 50 4.1.5 March, 2010 Event Case Study........................................................... 50 4.1.6 Significant East Coast Opening Event................................................. 58 4.1.7 Roes Welcome Sound Polynya ........................................................... 59 4.2 Discussion.................................................................................................... 60 4.2.1 Hudson Bay Coastal Polynya System ................................................. 60 4.2.2 Atmospheric Forcing Mechanisms ..................................................... 64 4.2.3 Freshwater Marine Coupling and Stratification ................................. 67 4.2.4 Biological Impacts .............................................................................. 70 4.3 Suggested Further Research ....................................................................... 71 5 Conclusion ...................................................................................................... 74 6 Appendix ......................................................................................................... 76 6.1 Works Cited ................................................................................................. 76 6.2 Citations for Data Sources .......................................................................... 92 6.3 Projection Details ........................................................................................ 93 6.4 Adjusted Date of Year Key .......................................................................... 94 6.5 Eigenvalues for Principal Components Analysis ......................................... 94 LIST OF TABLES Table 2-1 - Use of Sea Ice Thresholds in Literature ................................................. 18 Table 3-1 - Geometry of Subregions. ...................................................................... 32 Table 4-1 - Northwest Polygon Consolidated Period .............................................. 40 Table 4-2 - Descriptive Statistics of Polynya Events ................................................ 45 Table 4-3 - Spearman's Rank Correlation between OWE and U-Wind ................... 49 v LIST OF FIGURES Figure 3-1 –(a) Northwest Hudson Bay Area of Interest; (b) Subregions (refer to Table 2-1) ................................................................................................................. 31 Figure 4-1 - Examples of Polynya Maxima ............................................................... 41 Figure 4-2 – Same date comparison of SIC (a) to SIE (b) – March 4, 2008 .............. 42 Figure 4-3 - Sea Ice Extent in Northwestern Hudson Bay (Region 5). ..................... 44 Figure 4-4 – Seasonal cumulative open water extent in Northwest study area ..... 46 Figure 4-5 - Mean Polynya SIE (a) and Count of separate
Load more

Recommended publications
  • Reliability-Based Sea-Ice Parameters for Design of Offshore Structures
    Reliability-based sea-ice parameters for design of offshore structures BSEE contract number: E13PC00020 Presented by: University of Alaska Anchorage; College of Engineering Project Team: Hajo Eicken (UAF) Andy Mahoney (UAF) Andrew T. Metzger (UAA) Vincent Valenti (UAA) December, 2015 Abstract: The intent of this study was to supplement the ISO 19906 Standard: Petroleum and Natural Gas Industries - Arctic Offshore Structures (i.e., the Normative). This supplement provides additional sea-ice information, for US waters in both the Chukchi and Beaufort seas, in a format consistent with the philosophy of the Normative. Currently, implementation of ISO 19906 in US waters is questionable due the lack of sea- ice design criteria. Appendices B.7 (Beaufort Sea) and B.8 (Chukchi Sea) of ISO 19906 are intended to provide this information but the data is not in a format consistent with the philosophy of the Normative – i.e., a reliability (probability)-based format. A full complement of design values for the regions covered in B.7 and B.8 is required to implement the normative provisions and, ultimately, produce a safe and reliable offshore structural design that can successfully survive demands from sea-ice. The work here included an extensive literature review and detailed analysis of sixteen (16) seasons of under-ice measurements from lease sites in the Chukchi and Beaufort seas. The analyses have further characterized ice cover and identified the most acute values for certain ice features. Also included in this study is a means to identify a critical keel depth with a low probability of being exceeded (conversely a high reliability of not being exceeded/failing) in a particular timeframe.
    [Show full text]
  • The University of Kansas Center for Research, Inc
    INASA-CR-156 614 ) RADAR SYSTEUS MISSION, FOR A POLAR N78-10345 VOLUHE 3, APPENDICES A-D, S, Final T Report (Kansas Univ.) 143 HC A07/MF A01 p CSCL 171 Unclas G3/32 52326 THE UNIVERSITY OF KANSAS CENTER FOR RESEARCH, INC. 2291 Irving Hill Rd.-Campus West Lawrence, Kansas 66044 THE UNIVERSITY OF KANSAS SPACE TECHNOLOGY CENTER Raymond Nichols Hall 2291 Irving Hill Drive-Campus West Lawrence, Kansas 66045 Telephone: RADAR SYSTEMS FOR A POLAR MISSION FINAL REPORT Remote Sensing Laboratory RSL Technical Report 291-2 Volume IfI (This Volume contains Appendices Afland S-T. Appendices D, S, and T should be considered as addenda to Volume IV of TR 295-3, "Radar Systems for the Water Resources Mission - Final Report," CONTRACT NAS 5-22384; ihich was published in June, 1976.) R. K. Moore J. P. Claassen R.:L. Erickson R. K. T. Fong, B..C. Hanson M' J. K6men S. B. McMillan S. K. Parashar June, 1976 Supported by: NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Goddard Space Flight Center Greenbelt, Maryland 20771 CONTRACT NAS 5-22325 CRES 1 07 11 REMOTE SENSING LABORATORY THE UNIVERSITY OF KANSAS SPACE TECHNOLOGY CENTER- Raymond Nichols Hall 2291 Irving Hill Drive-Campus West Lawrence, Kansas 66045 Telephone: STATE OF THE ART - RADAR MEASUREMENT OF SEA ICE RSL Technical Report 291-1 Remote Sensing Laboratory S. K. Parashar December 1975 Supported by: NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Goddard Space Flight Center Greenbelt, Maryland 20771 CONTRACT NAS 5-22325 Iii tD~j REMOTE SENSING LABORATORY TABLE OF CONTENTS page ABSTRACT ................................................ 1.0 INTRODUCTION ...................................... 1 2.0 CHARACTERISTICS OF SEA ICE .........................
    [Show full text]
  • Sea Ice Thickness Retrieval Model for 1.4 Ghz Radiometry
    The Cryosphere Discuss., 3, 995–1022, 2009 The Cryosphere www.the-cryosphere-discuss.net/3/995/2009/ Discussions TCD © Author(s) 2009. This work is distributed under 3, 995–1022, 2009 the Creative Commons Attribution 3.0 License. This discussion paper is/has been under review for the journal The Cryosphere (TC). Sea ice thickness Please refer to the corresponding final paper in TC if available. retrieval model for 1.4 GHz radiometry L. Kaleschke et al. A sea ice thickness retrieval model for Title Page Abstract Introduction 1.4 GHz radiometry and application to Conclusions References airborne measurements over low salinity Tables Figures sea ice J I 1 1 2 3 4 L. Kaleschke , N. Maaß , C. Haas , S. Hendricks , G. Heygster , and J I R. T. Tonboe5 Back Close 1Institute of Oceanography, University of Hamburg, Bundesstraße 53, 20146 Hamburg, Germany Full Screen / Esc 2Department of Earth & Atmospheric Sciences, University of Alberta Edmonton, Alberta T6G 2E3, Canada Printer-friendly Version 3Alfred Wegener Institute for Polar and Marine Research, Bussestr. 24, 27570 Bremerhaven, Germany Interactive Discussion 4Institute of Environmental Physics, University of Bremen, P.O. Box 330440, Germany 995 TCD 5 Center for Ocean & Ice, Danish Meteorological Institute, Lyngbyvej 100, 3, 995–1022, 2009 2100 Copenhagen, Denmark Received: 19 October 2009 – Accepted: 6 November 2009 – Published: 18 November 2009 Sea ice thickness retrieval model for 1.4 Correspondence to: L. Kaleschke ([email protected]) GHz radiometry Published by Copernicus Publications on behalf of the European Geosciences Union. L. Kaleschke et al. Title Page Abstract Introduction Conclusions References Tables Figures J I J I Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion 996 Abstract TCD In preparation for the European Space Agency’s (ESA) Soil Moisture and Ocean Salin- ity (SMOS) mission we investigated the potential of L-band (1.4 GHz) radiometery to 3, 995–1022, 2009 measure sea ice thickness.
    [Show full text]
  • Airborne Electromagnetic Measurements of Sea Ice Thickness: Methods and Applications
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Electronic Publication Information Center Airborne electromagnetic measurements of sea ice thickness: methods and applications Christian Haas, Sibylle Goebell, Stefan Hendricks, Torge Martin, Andreas Pfaffling, Carola von Saldern, AWI Abstract Alfred Wegener Institute operates two helicopter-borne electromagnetic (EM) sounding devices dedicated to the measurement of sea ice thickness. With the method, level total (ice plus snow) thickness can be determined with an accuracy of ±0.1 m. However, due to the footprint of the method and due to the porosity of unconsolidated ridge keels, deformed ice thickness can be strongly underestimated. The paper summarizes the retrieval of ice thickness from the EM data, and shows some validation results. Applications of the methods show that level ice thickness has decreased by 20% in the Transpolar drift between 1991 and 2001, but remained constant at 2.0 m between 2001 and 2004. Surveys in 2004 and 2005 in the Lincoln Sea revealed very thick ice with modal thicknesses between 3.9 and 4.2 m, and an increase of mean ice thickness from 4.67 m in 2004 to 5.18 m in 2005. As the EM instruments also comprise a laser altimeter and a differential GPS receiver (DGPS), independent measurements of ridge distributions and surface roughness can be obtained. In addition, coincident measurements of total thickness and surface elevation allow the retrieval of snow thickness. 1. Introduction Sea ice thickness is one of the most important parameters for climate studies and ice engineering problems.
    [Show full text]
  • Inventory of U.S. Ocean and Coastal Facilities
    APPENDIX 5 INVENTORY OF U.S. OCEAN AND COASTAL FACILITIES GOVERNORS’ DRAFT MARCH 2004 YOU MAY ELECTRONICALLY DOWNLOAD THIS DOCUMENT FROM THE U.S. COMMISSION ON OCEAN POLICY WEB SITE: HTTP://WWW.OCEANCOMMISSION.GOV THIS DOCUMENT MAY BE CITED AS FOLLOWS: APPENDIX 5, PRELIMINARY REPORT OF THE U.S. COMMISSION ON OCEAN POLICY GOVERNORS’ DRAFT, WASHINGTON, D.C., MARCH 2004 CHAPTER 1. INTRODUCTION to the INVENTORY 1 1.1 Purpose of the Inventory 2 1.2 Methodology 2 1.3 Using This Appendix 4 CHAPTER 2. MARITIME COMMERCE and TRANSPORTATION 5 2.1 Marine Transportation System 7 2.1.1 Overview of U.S. Waterborne Commerce 7 2.1.2 Shipping Vessels 8 2.1.3 Trends in Shipping and Cargo Movement 10 2.1.4 U.S. Coastal Ports System 11 2.1.4.1 Deep-Draft Ports 12 2.1.4.2 Shallow Ports 14 2.1.5 Marine Terminals and Intermodal Connections 14 2.1.6 U.S. Merchant Marine 16 2.1.6.1 Naval Fleet Auxiliary Force 18 2.1.6.2 Special Missions Program 18 2.1.6.3 Pre-positioning Program 19 2.1.6.4 Sealift Program 19 2.1.6.5 Ship Introduction Program 19 2.1.6.6 Ready Reserve Force 19 2.1.6.7 National Defense Reserve Fleet 20 2.1.7 U.S. Passenger Ferry System 20 2.1.8 U.S. Cruise Industry 22 2.1.9 U.S. Shipbuilding and Repair Industries 25 2.1.9.1 Private Shipyards 25 2.1.9.1.1 Major Shipyards 25 2.1.9.1.2 Small and Mid-sized Shipyards 29 2.1.9.2 Employment and Economic Impacts 30 2.1.9.3 Public Shipyards 32 2.1.9.3.1 U.S.
    [Show full text]
  • Long-Term Plan for Arctic Environmental Research JCAR
    Long-term Plan for Arctic Environmental Research Japan Consortium for Arctic Environmental Research April 2015 Preface The JCAR was founded in May of 2011 and has as many as 384 supporting members as of August 2014. Behind the birth of the JCAR was the idea of persons involved in Arctic research to develop previous efforts for Japanese research in the Arctic in a new form. Up to now, many Japanese researchers have visited Arctic. However, although their individual research abilities are high, results from Japan are often not well remarked in the international movements. As these researchers travel to the Arctic as a small group and short timealone, they recognize that continuity from past observations, knowledge of the trends of other researchers, cooperation frameworks, and arrangement are the weak points of Japanese research. For activities like these, the research is inevitably temporary, and the vision or realization of long-term observations becomes impossible. The founding of JCAR is expected to improve the exchange information on activities conducted by every researcher, to have future directions, and to obtain partners for potential cooperative research. The importance of establishing a long-term vision of Japanese Arctic environmental research within that kind of activity was considered and recommended in a midterm report (August, 2010) after discussion at the 2010 meeting of the Arctic Research Working Group of the Ministry of Education, Culture, Sports, Science and Technology. In the fall of 2011, the same year that JCAR was founded, the GRENE Arctic Climate Change Research Project started. In the following year, 2012, the minimum sea ice extent of the Arctic Ocean in the summer was recorded.
    [Show full text]
  • Propagation of an Ice Shelf Water Plume Beneath Sea Ice in Mcmurdo Sound, Antarctica
    Propagation of an Ice Shelf Water Plume beneath Sea Ice in McMurdo Sound, Antarctica Kenneth Hughes A thesis submitted in fulfilment of the degree of Master of Science at the University of Otago, Dunedin, New Zealand October 2013 Abstract A cold water mass, termed Ice Shelf Water, appears to exist for much of the year beneath the sea ice cover in western McMurdo Sound, Antarctica, yet it is present for only a few months in the east. In an east{west transect taken 3 km in front of the McMurdo Ice Shelf edge during spring tide in late November 2011 and repeated during neap tide in early December, this water mass was observed throughout the entire water column at the two, of four, westernmost sites. In situ supercooling was observed at all sites and, at the coldest site, was measured to depths of 60{73 m. Ice Shelf Water alters the sea ice fabric through the introduction of millimetre-sized ice crystals, termed frazil ice, that grow in supercooled water. Four first-year sea ice cores from the transect are analysed to determine the extent of the altered sea ice fabric, platelet ice, to provide a time-history of oceanographic conditions during the 2011 austral winter. The onset of platelet ice is delayed to greater depths in the core with distance eastward along the transect, which suggests that the lateral extent of Ice Shelf Water flowing into McMurdo Sound from beneath the ice shelf expands from the west throughout winter. A steady-state, one-dimensional Ice Shelf Water plume model is adapted for McMurdo Sound to predict the evolution of this supercooled water emerging from beneath the McMurdo Ice Shelf at the site where the coldest water was observed.
    [Show full text]
  • Technology and Operations
    Part Two Technology and Operations Part Two Overview he following four chapters examine the state of The opportunities were prioritized with a view industry’s capability to explore for and develop toward the magnitude of impact they could have T oil and gas resources in an arctic environment. on making substantial, measurable progress toward The spectrum of technologies and operations con- facilitating prudent U.S. Arctic development in the sidered include (1) characterization of the ice envi- next several decades. The items in the table are ronment; (2) exploring for, drilling, producing, and prioritized first on the basis of priority for prudent exporting oil; (3) logistics and infrastructure; and development of U.S. offshore Arctic oil. Categories (4) preventing and responding to oil spills. The objec- of H (high), M/H (medium high), M (medium), and tive of the chapters is to describe the current state L (low) were assigned. Items within each of the cate- of art and then explore opportunities for conducting gories were further prioritized by giving preference to research or pursuing technology/capability enhance- technologies that facilitate Exploration or Both over ments that could materially facilitate prudent devel- Production. No attempt was made to further priori- opment in the U.S. offshore Arctic. Opportunities tize items within a category or to develop an overall were sought that address the multiple dimensions of prioritization. Hence, the numerical order of items prudent development. Accordingly, we asked what in a category does not imply prioritization of say, one enhancements could: high priority item versus another, with the exception y Make operations safer? of demoting those that pertain to Production only.
    [Show full text]
  • A New Apparatus for Monitoring Sea Ice Thickness Based on the Magnetostrictive-Delay-Line Principle
    818 JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY VOLUME 26 A New Apparatus for Monitoring Sea Ice Thickness Based on the Magnetostrictive-Delay-Line Principle RUIBO LEI AND ZHIJUN LI State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian, China YANFENG CHENG Polar Research Institute of China, Shanghai, China XIN WANG State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian, China YAO CHEN Wu Xi Fengrun Science and Technology Ltd., Wuxi, China (Manuscript received 10 December 2007, in final form 11 October 2008) ABSTRACT High-precision ice thickness observations are required to gain a better understanding of ocean–ice–atmosphere interactions and to validate numerical sea ice models. A new apparatus for monitoring sea ice and snow thickness has been developed, based on the magnetostrictive-delay-line (MDL) principle for positioning sensors. This system is suited for monitoring fixed measurement sites on undeformed ice. The apparatus presented herein has been tested on landfast ice near Zhongshan Station, East Antarctica, for about 6 months during the austral autumn and winter of 2006; valid data records from the deployment are available for more than 90% of the deployment’s duration. The apparatus’s precision has been estimated to be 60.002 m for the deployment. Therefore, it is possible that this apparatus may become a standard for sea ice/snow thickness monitoring. 1. Introduction ice energy equilibrium, and investigating flooding on ice surfaces (Kawamura et al. 1997; Saloranta 2000; Eicken Sea ice plays an important role in the global climate et al. 2004). Although for an area as large as the Arctic system (Vavrus and Harrison 2003) and also is the most and Antarctica, and even a global scale, the final ex- sensitive indicator of local and global climate change pression of the ocean–ice–atmosphere interactions is (Vinnikov et al.
    [Show full text]
  • Airborne Electromagnetic Measurements of Sea Ice Thickness: Methods and Applications
    Airborne electromagnetic measurements of sea ice thickness: methods and applications Christian Haas, Sibylle Goebell, Stefan Hendricks, Torge Martin, Andreas Pfaffling, Carola von Saldern, AWI Abstract Alfred Wegener Institute operates two helicopter-borne electromagnetic (EM) sounding devices dedicated to the measurement of sea ice thickness. With the method, level total (ice plus snow) thickness can be determined with an accuracy of ±0.1 m. However, due to the footprint of the method and due to the porosity of unconsolidated ridge keels, deformed ice thickness can be strongly underestimated. The paper summarizes the retrieval of ice thickness from the EM data, and shows some validation results. Applications of the methods show that level ice thickness has decreased by 20% in the Transpolar drift between 1991 and 2001, but remained constant at 2.0 m between 2001 and 2004. Surveys in 2004 and 2005 in the Lincoln Sea revealed very thick ice with modal thicknesses between 3.9 and 4.2 m, and an increase of mean ice thickness from 4.67 m in 2004 to 5.18 m in 2005. As the EM instruments also comprise a laser altimeter and a differential GPS receiver (DGPS), independent measurements of ridge distributions and surface roughness can be obtained. In addition, coincident measurements of total thickness and surface elevation allow the retrieval of snow thickness. 1. Introduction Sea ice thickness is one of the most important parameters for climate studies and ice engineering problems. Apart from upward looking sonar (ULS) profiling, electromagnetic induction (EM) thickness sounding has become an accurate and efficient method for thickness profiling and can be operated on the ice, from ships (Haas, 1998; Haas et al., 1999), or from structures like lighthouses or oil rigs (Haas and Jochmann, 2003).
    [Show full text]
  • Sea Ice Modeling and Observing Workshop Report
    Sea Ice Modeling and Observing Workshop Report 5 – 7 June 2013 Tromsø, Norway Executive Summary The sea ice covers of the polar oceans are a critical element of the global system. With support from the Research Council of Norway, CliC, the International Arctic Science Committee (IASC) and the Scientific Committee on Antarctic Research (SCAR), 48 researchers from 13 countries, including 10 early career scientists, met from June 5-7, 2013 in Tromso, Norway to discuss the next steps in better integrating sea ice observations and modeling. The group included field experimentalists, remote sensing specialists, and sea ice and climate modelers. The workshop featured overview presentations on sea ice observations, models, remote sensing, and data archiving plus ample time for group discussions. Five 7-9 person teams consisting of scientists from a mixture of areas of expertise were assembled to develop a list of key gaps of knowledge within sea ice observations and models. Targeted activities that could close some of these gaps were proposed with separate short (6 months to a year), medium (1-2 years), and long (3 years or more) term goals. A common theme from these projects was the need for standardization of sea ice observation data from the Arctic, developing and implementing a standardized, computerized ship-based ice observation protocols and creating an online center for summarizing ongoing field activities. The combination of ASPeCt and IceWatch efforts will help create an ongoing inventory of sea ice and sea ice related datasets for both Arctic and Antarctic This meeting identified key areas where we need to improve our understanding of sea ice properties and processes and enhance our ability to model sea ice on different spatial and temporal scales.
    [Show full text]
  • The Arctic Sea-Ice Navigability Index
    RESEARCH COMMUNICATIONS The Arctic sea-ice navigability index This study presents an index on a numerical scale of 0– 100 to assess navigability through Arctic sea ice solely using remote-sensing data products. Mukesh Gupta The fundamental premise in defining an index for Université catholique de Louvain, Faculty of Sciences, navigability is whether there is unbreakable (or breaka- Earth and Life Institute, Georges Lemaître Centre for Earth and ble) sea ice in the path of icebreakers. Some important Climate Research, Place Louis Pasteur 3, SC10-L4.03.08, B-1348 Louvain-la-Neuve, Belgium geophysical variables responsible for determining if the icebreakers can easily break the ice are ice strength, ice A rapidly changing sea-ice regime in the Arctic de- drift, ice thickness, ice concentration, melt pond fraction, mands an index that could provide a priori informa- and whether the ice is fast or pack ice. Other primary fac- tion to icebreakers for hazard-free navigation through tors that influence ice motion and navigation are atmo- ice across the Arctic. This study presents a new sea-ice spheric factors (air temperature, surface winds) and navigability index, solely based on daily available re- oceanic factors (swell, ocean circulation). It is much easi- mote-sensing products. The index has a numerical er to navigate during summer as the ice is weaker and scale from 0 to 100 that represents the navigability of often laden with melt ponds. Sea-ice thickness, as we icebreakers through sea ice. High mobility of sea ice know, has significantly reduced throughout the Arctic, implies that there may be fragmented ice floes that are except in the perennial sea-ice regions, e.g.
    [Show full text]