DOCSLIB.ORG

Frazil Ice: a Review of Its Properties, with a Selected Bibliography Williams, G

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Frazil Ice: a Review of Its Properties, with a Selected Bibliography Williams, G NRC Publications Archive Archives des publications du CNRC Frazil ice: a review of its properties, with a selected bibliography Williams, G. P. This publication could be one of several versions: author’s original, accepted manuscript or the publisher’s version. / La version de cette publication peut être l’une des suivantes : la version prépublication de l’auteur, la version acceptée du manuscrit ou la version de l’éditeur. Publisher’s version / Version de l'éditeur: Engineering Journal, 42, 11, pp. 55-60, 1959-12-01 NRC Publications Record / Notice d'Archives des publications de CNRC: https://nrc-publications.canada.ca/eng/view/object/?id=f683a087-d82c-4542-81e8-398c95993824 https://publications-cnrc.canada.ca/fra/voir/objet/?id=f683a087-d82c-4542-81e8-398c95993824 Access and use of this website and the material on it are subject to the Terms and Conditions set forth at https://nrc-publications.canada.ca/eng/copyright READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE. L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site https://publications-cnrc.canada.ca/fra/droits LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB. Questions? Contact the NRC Publications Archive team at [email protected]. If you wish to email the authors directly, please see the first page of the publication for their contact information. Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à [email protected]. lt Ser TiIl l N21t2 NATIONAL RESEARCH COUNCIL CANADA DIVISION OF BUILDING RESEARCH FRAZIL ICE A Reuiewof its Propertieswith a SelectedBibliography by G. P. Williams Ati Ai--t'i;i) REPRINTED FROM THE ENGINEERING IOURNAL voL. 42, NO. tt, NOVEMBER 1959,p.55-60 "':'iifioti?1'n TECHNICAL PAPER NO. 8T FEBr 1960 OF THE couRClL RltloNAL RESEARCH DIVISION OF BUILDING RESEARCH OTTAWA PRICE IO CENTS DECEMRER T959 This publication is being distributed by the Division of Building Research of the National Research Council as a contribution towards better building in Canada. It should not tre reproduced in whole or in part, without permission of the original publisher. The Division would be glad to be of assistancein obtaining such permission. Publications of the Division of Building Research may be 'obtained by mailing the appropriate remittance, (a Bank, Express, or Post Office Money Order or a cheque made payable at par in Ottawa, to the Receiver General of Canada, credit National Research Council) to the National Research Council, Ottawa. Stamps are not acceptable. A coupon system has been introduced to make pavments for publica- tions relatively simple. Coupons are available in denominations of 5, 25, and 50 cents, and may be obtained by making a remittance as indicated above. These coupons may be used for the purchase of all National Research Council publications including specifications of the Canadian Government Specifica- tions Board. jlililrl ililililil13 FRAZILICE A Reuiew its Properties. "f With a SelectedBibliography G. P. Williams Research Officer, Snow and Ice Section, Dioisi,on of Bui'ldi'ng Research, National Research Council, Ottawa 2, Ont' Tf-f HENEVER supercooledwater This report reviews the theory of frazil ice formation and the main factors l[/ vY rn reservolrs, lakes or rivers which cause- formations. The methods of forecasting ftazil ice and the design and also included. Although the frazil ice problem has comes in contact with hyd,ro-electric remedial considerations are been solved at many sites in Canada, this _review summarizes investigations which plant intakes, lvater supply intakes, would not generally be available to Canadian engineers. ilrigation and water supply canals, there is a danger of serious clogging Theory of Formation face water exposed to the heat loss because of fuazil ice. Frazil ice oc- Ice is formed on the calm water will be interchanged with water from curring in large rivers is a naviga- of small lakes and stagnant pools lower depths so that a mass of water tional hazard and can be the cause when the loss of heat to the atmos- down to different depths, depending of serious ice jams. In Canada the phere by radiation, convection and on the degree of turbulence, will be work of Barnesl is the first major evaporation results in the supercool- cooled to 0"C without ice formation. effort to present detailed summaries ing of the surface water. In this If the cooling continues the water near will of available information on frazil ice static type of ice formation described the surface be supercooled hundredths degree (Alt- formation and occurrence. Since then by Devik2 the crystallization begins a few of a At in many investigations have been car- partly from solid matter on the beach berg3). a certain stage this frazil particles will ried out, notably in Russia and other and from solid material suspended supercooling, ice European countries. As no publica- or floating in the water. If the water start to form. tion is available in English, appar- remains at rest and the cooling con- In their early development, frazil ,circular ently, which summarizes these more tinues. a surface sheet of ice ii rap- ice particles are thin discs. recent developments, this survey of idly formed. Frequently, the particles are of ir- existing information on frazil ice has With dynamic ice formation as in regular outline but the edges are in- been prepared, accompanied by a running water or on the surface of variably rounded as shown in the ex- number of selected references. lake water disturbed bv wind. sur- cellent photographs by Schaefera. As growth proceeds, however, flat den- drites grow out from the edge of the eventually producing Fig. I Stagesin frazil ice formation. flat discs, the needle-like fragments commonly rec- ognized as frazil ice. Under favourable cooling,conditions these fragments STAGE I STAGE 4 rapidly form and group into the large spongy masses that cause so much SURFACE COOLING FURTHERCOOLING COOLING COOLING CONTINUES CONTINUES trouble on underwater installations. Figure I illustrates the different stages oO in frazil ice formation. Figure 2 shows TURBULENT some micro photographs of frazil ice [,lIXING in different stages of growth. A similar type of formation occurs in lake water when supercooling co- ooo inciding with stlong wave-action re- sults in agglomeration (Wilson5). HIGH CONCENTRATIONOF NEEDLE.LiKE CE NEEDLE S USTERSOF FRAZlL Even though the general nature of CIRCULARDISCOIDS DENDRITESGRO CLUSTERINGTO- ICE CONGLOMERATE flazil ice folmation has been known TORMfD OUT FROII DISCOIDSGETIIER FLOATING TO SURfACE AND BI]II-[]NG (JP ON fol a long time there is still argu- I]NDERWATER OBJECTS rnent and confusion in the literature Frazil ice particles floating on water Frazil ice particles changing shape Frazil ice particles growing and chang- surface. water surface. ing pattern at water surface. Fig. 2 Micro photographs of frazil ice in different stages of growth. regarding the phenomenon (Timon- formation in water conclude that the the stream much the same as water- offo, LamborT). rate of growth of discoids (or frazil soaked leaves are carried underwater Supercooling atTd Nucleation. In- ice particles) is a function of the rate in a turbulent stream. vestigators seem to agree that super- of cooling of the water and the Schaefera estimates that the vol- cooled water often exists in streams for number of discoids. Their photo- ume concentration of frazil ice ao- long periods - even for days under graphs show clearly the development proaches 106 per cubic meter in h]is favourable conditions8. There is ar.- of circulal discoids into stellar crys- observations of frazil ice on the Mo- gument, however, regarding the tals. Their studies show that with hawk river in 1950. Frazil ice parti- amount of supercooling, although it supercooling from 0"C to -0.3"C, cles will adhere to each other and is generally assumed that it will rarely discoids and spicules are produced, also build up on underwater objects exceed .01"C in natural streams and and from -0.6'C to -0.9"C spicules causing many problems. According lakes (Schaefera).The theory of super'- only are produced. to Piotrovichlo, when water is super- cooUng is still a matter of some Much of the work done in recent cooled there is a strong increase disagreement. Dorseye indicates that years on the physics of supercooled in the cohesion forces between ice there are two theolies to explain the water droplets in the atmosphere is crystals and in the adhesion of ice freezing of water and the phenome- of relevant interest to investiqators crystals with stones, wood, metal and non of supercooling. In one, freez- of flazil ice (SchaeferrB). other objects in the water. Schaefer ing is considered to be initiated by Frazil lce Properties. The frazil ice suggests that the laminar type of certain aggregates of water molecules discoids vary in size. Schaefera ob- build-up indicates regelation between called ice molecules. The other theorv serves particles with a range of thick- these ice particles. considers freezing to begin ut ness 25 to 100 microns for particles Piotrovich also suggests that, as heterogeneous singularities, i.e., for- 1000 to 5000 microns in diameter. ice does not adhere strongly to cer- eign particles in the water which Hubbardla reports thickness almost tain substances as plastics of purely serve as nuclei. Dorsey combines ele- identical to those reported by organic composition, these may be ments of both theories. He distin- Schaefer. Altberg3 ,claims that dis- used as coatings to protect against guishes between an embryo comprised coids up to several centimetres in underwater ice accumulations.
Load more

Recommended publications
  • River Ice Management in North America
    RIVER ICE MANAGEMENT IN NORTH AMERICA REPORT 2015:202 HYDRO POWER River ice management in North America MARCEL PAUL RAYMOND ENERGIE SYLVAIN ROBERT ISBN 978-91-7673-202-1 | © 2015 ENERGIFORSK Energiforsk AB | Phone: 08-677 25 30 | E-mail: [email protected] | www.energiforsk.se RIVER ICE MANAGEMENT IN NORTH AMERICA Foreword This report describes the most used ice control practices applied to hydroelectric generation in North America, with a special emphasis on practical considerations. The subjects covered include the control of ice cover formation and decay, ice jamming, frazil ice at the water intakes, and their impact on the optimization of power generation and on the riparians. This report was prepared by Marcel Paul Raymond Energie for the benefit of HUVA - Energiforsk’s working group for hydrological development. HUVA incorporates R&D- projects, surveys, education, seminars and standardization. The following are delegates in the HUVA-group: Peter Calla, Vattenregleringsföretagen (ordf.) Björn Norell, Vattenregleringsföretagen Stefan Busse, E.ON Vattenkraft Johan E. Andersson, Fortum Emma Wikner, Statkraft Knut Sand, Statkraft Susanne Nyström, Vattenfall Mikael Sundby, Vattenfall Lars Pettersson, Skellefteälvens vattenregleringsföretag Cristian Andersson, Energiforsk E.ON Vattenkraft Sverige AB, Fortum Generation AB, Holmen Energi AB, Jämtkraft AB, Karlstads Energi AB, Skellefteå Kraft AB, Sollefteåforsens AB, Statkraft Sverige AB, Umeå Energi AB and Vattenfall Vattenkraft AB partivipates in HUVA. Stockholm, November 2015 Cristian
    [Show full text]
  • Sea Ice Growth and Decay a Remote Sensing Perspective Sea Ice Growth & Decay
    Sea Ice Growth And Decay A Remote Sensing Perspective Sea Ice Growth & Decay Add snow here Loss of Sea Ice in the Arctic Donald K. Perovich and Jacqueline A. Richter-Menge Annual Review of Marine Science 2009 1:1, 417-441 Sea Ice Remote Sensing Method Physical Property Sensor Type Geophysical Variable Passive Microwave Surface Emissivity Radiometer Sea Ice Concentration ~ 1 – 100 GHz Sea Ice Classification Sea Ice Motion Thin Sea Ice Thickness (Snow Depth) Active Microwave Backscatter SAR Sea Ice Classification Sea Ice Motion Very Thin Sea Ice Thickness Scatterometer Sea Ice Type Altimeter Sea Ice Thickness (Snow Depth) Optical Spectral Albedo Spectrometer Floe Sizes Distribution Melt Pond Coverage Melt Pond Depth Infrared Surface Emissivity Radiometer Sea Ice Surface Temperature Thin Sea Ice Thickness Laser Backscatter Altimeter Sea Ice Thickness What are the main processes of sea ice growth & decay? How do they affect sea ice remote sensing? How to observe these processes independently? Formation Redistribution Snow Surface Melt & Growth Processes Annual Cycle of Sea Ice Sea Ice Extent Area covered at least with 15% sea ice (according to passive microwave data) Long-Term Sea Ice Trends Sea Ice Extent Sea Ice Thickness Passive Microwave Time Series Submarines, Moorings, Airborne Surveys Arctic Antarctic No comparable sea ice thickness data record Sea Ice Age & Type Sea Ice Age Sea Ice Type Model with observed ice drift & concentration Passive & Active Microwave Formation Redistribution Snow Surface Melt & Growth Processes Early Sea Ice
    [Show full text]
  • Frazil-Ice Nucleation by Mass-Exchange Processes at the Air- Water Interface
    J ournal oIG/acio logy, V o !. 19, No. 8 1, 197 7 FRAZIL-ICE NUCLEATION BY MASS-EXCHANGE PROCESSES AT THE AIR- WATER INTERFACE By T. E. O ST E RKAMP':' (Geophysical Institute, University of Alaska, Fairbanks, A laska 99701, U .S.A. ) AosTRACT. T he physical requirem ents for proposed frazil-ice nucleati on theori es are reviewed in the light of recent observations on frazil-ice forma tion. It is concluded that sponta neous heterogeneous nucleation in a thin supercooled surface la yer of wa ter is not a via ble mechanism for frazil-ice nucleation. E fforts to observe crys ta l multiplicati on b y b order ice have n o t been successful. The mass-excha nge m echanism proposed by O sterka mp and others ( 1974) has been gen era li zed to include splashing, wind spray, bubble bursting, evapo ra tion, a nd ma teria l tha t originates a t a dista nce from the strea m (e. g. snow, frost, ice pa rticles, cold orga nic m a teria l, a nd cold soil pa rticles). I t is shown that these mass-exchange processes ca n account for frazil-ice nucleation under a wide ra nge of phys ical a nd meteorological conditions. It is suggested that secondary nuclea tion may be responsible for large frazil-ice concentra tions in streams and rivers. R EsuME. JVllcieatioll de la glace dll ''.fra zil'' par des processus d'echallges de masses a I'illlerface air ell eall. O n a rev u les conditions physiques requises pa r les theories p our la nucleation d e la glace du " frazil " a la lumicre de recentes observations sur cette forma ti on.
    [Show full text]
  • Snow and Ice Control Around Structures - George D
    COLD REGIONS SCIENCE AND MARINE TECHNOLOGY - Snow and Ice Control Around Structures - George D. Ashton SNOW AND ICE CONTROL AROUND STRUCTURES George D. Ashton Consultant, Lebanon, NH 03766 Keywords: ice jams, ice control, flooding, snow drifting, snow loads, river ice Contents 1. Introduction 2. Nature of ice jams 2.1. Frazil Ice 2.1.1. Hanging Dams 2.1.2. Blockage of Intakes 2.2. Breakup Ice Jams 3. Control of ice jams 3.1. Frazil Ice Jams 3.2. Breakup Ice Jams 3.2.1. Ice Suppression 3.2.2. Dikes 3.2.3. Ice Booms 3.2.4. Ice Control Structures 3.2.5. Ice Removal 3.2.6. Ice Breaking 3.2.7. Ice Weakening 3.2.8. Blasting 4. Other Ice Control Techniques 4.1. Air Bubbler Systems 4.1.1. Requirements 4.1.2. Limitations 4.1.3. Operation 4.2. Other Ice Control Techniques 5. Snow control around structures 5.1. Buildings 5.1.1. Snow UNESCOLoads on Roofs – EOLSS 5.1.2. Blowing Snow 5.2. Roads 5.2.1 Snow Fences 6. Conclusion SAMPLE CHAPTERS Glossary Bibliography Biographical Sketch Summary Two main topics are treated here: control of ice jams including mitigation measures, and control of snow accumulations around structures. The nature of ice jams is described and the difference between jams formed of frazil ice and jams formed of broken ice is ©Encyclopedia of Life Support Systems (EOLSS) COLD REGIONS SCIENCE AND MARINE TECHNOLOGY - Snow and Ice Control Around Structures - George D. Ashton discussed. Also discussed are various ice control techniques used for specific problems.
    [Show full text]
  • The Effects of Rotation and Ice Shelf Topography on Frazil-Laden Ice Shelf Water Plumes
    The effects of rotation and ice shelf topography on frazil-laden ice shelf water plumes Article Published Version Holland, P. R. and Feltham, D. L. (2006) The effects of rotation and ice shelf topography on frazil-laden ice shelf water plumes. Journal of Physical Oceanography, 36 (12). pp. 2312-2327. ISSN 0022-3670 doi: https://doi.org/10.1175/JPO2970.1 Available at http://centaur.reading.ac.uk/34907/ It is advisable to refer to the publisher’s version if you intend to cite from the work. See Guidance on citing . Published version at: http://dx.doi.org/10.1175/JPO2970.1 To link to this article DOI: http://dx.doi.org/10.1175/JPO2970.1 Publisher: American Meteorological Society All outputs in CentAUR are protected by Intellectual Property Rights law, including copyright law. Copyright and IPR is retained by the creators or other copyright holders. Terms and conditions for use of this material are defined in the End User Agreement . www.reading.ac.uk/centaur CentAUR Central Archive at the University of Reading Reading’s research outputs online 2312 JOURNAL OF PHYSICAL OCEANOGRAPHY VOLUME 36 The Effects of Rotation and Ice Shelf Topography on Frazil-Laden Ice Shelf Water Plumes ϩ PAUL R. HOLLAND* AND DANIEL L. FELTHAM Centre for Polar Observation and Modelling, University College London, London, United Kingdom (Manuscript received 24 June 2005, in final form 20 April 2006) ABSTRACT A model of the dynamics and thermodynamics of a plume of meltwater at the base of an ice shelf is presented. Such ice shelf water plumes may become supercooled and deposit marine ice if they rise (because of the pressure decrease in the in situ freezing temperature), so the model incorporates both melting and freezing at the ice shelf base and a multiple-size-class model of frazil ice dynamics and deposition.
    [Show full text]
  • Laboratory Study of Frazil Ice Accumulation
    Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | The Cryosphere Discuss., 5, 1835–1886, 2011 The Cryosphere www.the-cryosphere-discuss.net/5/1835/2011/ Discussions TCD doi:10.5194/tcd-5-1835-2011 5, 1835–1886, 2011 © Author(s) 2011. CC Attribution 3.0 License. Laboratory study of This discussion paper is/has been under review for the journal The Cryosphere (TC). frazil ice Please refer to the corresponding final paper in TC if available. accumulation S. De la Rosa and S. Maus Laboratory study of frazil ice Title Page accumulation under wave conditions Abstract Introduction S. De la Rosa1,2 and S. Maus1 Conclusions References 1Geophysical Institute, University of Bergen, Allegaten´ 70, 5007, Bergen, Norway Tables Figures 2Nansen Environmental and Remote Sensing Center/Mohn-Sverdrup Center, Thormøhlensgate 47, 5006, Bergen, Norway J I Received: 27 May 2011 – Accepted: 13 June 2011 – Published: 8 July 2011 J I Correspondence to: S. De la Rosa ([email protected]) Back Close Published by Copernicus Publications on behalf of the European Geosciences Union. Full Screen / Esc Printer-friendly Version Interactive Discussion 1835 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Abstract TCD Ice growth in turbulent seawater is often accompanied by the accumulation of frazil ice crystals at its surface. The thickness and volume fraction of this ice layer play an 5, 1835–1886, 2011 important role in shaping the gradual transition from a loose to a solid ice cover, how- 5 ever, observations are very sparse. Here we analyse an extensive set of observations Laboratory study of of frazil ice, grown in two parallel tanks with controlled wave conditions and thermal frazil ice forcing, focusing on the first one to two days of grease ice accumulation.
    [Show full text]
  • Frazil Ice Formation in the Polar Oceans
    Frazil Ice Formation in the Polar Oceans Nikhil Vibhakar Radia Department of Earth Sciences, UCL A thesis submitted for the degree of Doctor of Philosophy Supervisor: D. L. Feltham August, 2013 1 I, Nikhil Vibhakar Radia, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. SIGNED 2 Abstract Areas of open ocean within the sea ice cover, known as leads and polynyas, expose ocean water directly to the cold atmosphere. In winter, these are regions of high sea ice production, and they play an important role in the mass balance of sea ice and the salt budget of the ocean. Sea ice formation is a complex process that starts with frazil ice crys- tal formation in supercooled waters, which grow and precipitate to the ocean surface to form grease ice, which eventually consolidates and turns into a layer of solid sea ice. This thesis looks at all three phases, concentrating on the first. Frazil ice comprises millimetre- sized crystals of ice that form in supercooled, turbulent water. They initially form through a process of seeding, and then grow and multiply through secondary nucleation, which is where smaller crystals break off from larger ones to create new nucleii for further growth. The increase in volume of frazil ice will continue to occur until there is no longer super- cooling in the water. The crystals eventually precipitate to the surface and pile up to form grease ice. The presence of grease ice at the ocean surface dampens the effects of waves and turbulence, which allows them to consolidate into a solid layer of ice.
    [Show full text]
  • Prevention of Frazil Ice Clogging of Water Intakes by Application of Heat
    REC-ERC-74-15 PREVENTION OF FRAZIL ICE CLOGGING OF WATER INTAKES BY APPLICATION OF HEAT Engineering and Research Center Bureau of Reclamation September 1974 Prepared for ICE RESEARCH MANAGEMENT COMMITTEE MS-230 (8-70) Bureau of R·~clamation TITLE PAGE 1. REPORT NO. REC-EF:C-74-15 4. TITLE: AND SUBTITLE 5. REPORT DATE September 1974 Prevention of Frazil Ice Clogging of Water 6. PERFORMING ORGANIZATION CODE Intakes by Application of Heat 7. AUTHOR(S) 8. PERFORMING ORGANIZATION REPORT NO. T. H. Logan REC-ERC-74-15 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. WORK UNIT NO. Bureau of Reclamation 11. CONTRACT OR GRANT NO. Engineeliing and Research Center Denver, Colorado 80225 13. TYPE OF REPORT AND PERIOD COVERED . SPONSORING AGENCY NAME AND 14. SPONSORING AGENCY CODE 15. SUPPLEMENTARY NOTES 16. ABSTRACT The phenomenon of ice formation in flowing water and the technology of heating trashrack bars to prevent clogging by frazil ice are reviewed. The report includes: (1) A description of frazil ice formation, (2) development of heat transfer equations for trashrack bars immersed in a fluid, (3) correlation between conditions assumed in developing the theoretical expressions and actual conditions present in a water intake, (4) economics of heating trash rack bars, (5) methods of heating trash rack bars, and (6) recommendations for future studies. Has 64 references. 17. KEY WORDS AND DOCUMENT ANALYSIS a. DESCRIPTORS-- I *frazil ice/ ice/ canals/ floating ice/ ice cover/ open channels/ slush/ intake structures/ *heatin~)/ trashracks/ barriers/ bibliographies b. IDENT/F /ERS-- c. COSATI Field/Group 13M 1. NO. OF PAGE Available from the National Technical Information Service, Operations 20 Division, Springfield, Virginia 22151.
    [Show full text]
  • Suspended Sediment Concentration and Deformation of Riverbed in a Frazil Jammed Reach
    1120 Suspended sediment concentration and deformation of riverbed in a frazil jammed reach Jueyi Sui, Desheng Wang, and Bryan W. Karney Abstract: The presence of ice in rivers affects hydrodynamic conditions through changes in both the river’s boundary conditions and its thermal regime. Therefore, the characteristics of sediment transport and the deformation of the river channel in ice-covered rivers are quite different from those experiencing conventional open channel flow. The variables of ice behavior, ice jamming extent, sediment transport, and deformation of the riverbed during ice periods are interre- lated on the basis of both physical arguments and field experiments of river ice jams in the Hequ Reach of the Yellow River. The characteristics of sediment concentration in water, frazil ice, and ice cover are described. Analyses have been made on the mechanism of the evolution of frazil jam and the associated adjustments in the riverbed. It has been found that the evolution of the ice jam and the deformation of the riverbed reinforce each other. The interrelationship between the particular features of evolution of ice jam and deformation of riverbed is summarized here in the form of regression relationships relating the hydraulic parameters of water under ice jams to the deformation-extent of the riverbed and the jamming-extent. Key words: deformation of riverbed, evolution of frazil jam, frazil jam, suspended load, sediment concentration. Résumé : La présence de glace dans des rivières affecte les conditions hydrodynamiques par le biais des conditions frontières et du régime thermique de la rivière. De ce fait, les caractéristiques du transport de sédiment et de la défor- mation du canal de la rivière pour des cas de rivières avec couvert de glace sont bien différentes de celles sous l’effet d’un écoulement à surface libre conventionnel.
    [Show full text]
  • Anchor Ice and Bottom-Freezing in High-Latitude Marine Sedimentary Environments: Observations from the Alaskan Beaufort Sea
    ANCHOR ICE AND BOTTOM-FREEZING IN HIGH-LATITUDE MARINE SEDIMENTARY ENVIRONMENTS: OBSERVATIONS FROM THE ALASKAN BEAUFORT SEA by Erk Reimnitz, E. W. Kempema, and P. W. Barnes U.S. Geological Survey Menlo Park, California 94025 Final Report Outer Continental Shelf Environmental Assessment Program Research Unit 205 1986 257 This report has also been published as U.S. Geological Survey Open-File Report 86-298. ACKNOWLEDGMENTS This study was funded in part by the Minerals Management Service, Department of the Interior, through interagency agreement with the National Oceanic and Atmospheric Administration, Department of Commerce, as part of the Alaska Outer Continental Shelf Environmental Assessment Program. We thank D. A. Cacchione for his thoughtful review of the manuscript. TABLE OF CONTENTS Page ACKNOWLEDGMENTS . ...259 INTRODUCTION . 263 REGIONAL SETTING . ...264 INDIRECT EVIDENCE FOR ANCHOR ICE IN THE BEAUFORT SEA . ...266 DIVER OBSERVATIONS OF ANCHOR ICE AND ICE-BONDED SEDIMENTS . ...271 DISCUSSION AND CONCLUSION . ...274 REFERENCES CITED . ...278 INTRODUCTION As early as 1705 sailors observed that rivers sometimes begin to freeze from the bottom (Barnes, 1928; Piotrovich, 1956). Anchor ice has been observed also in lakes and the sea (Zubov, 1945; Dayton, et al., 1969; Foulds and Wigle, 1977; Martin, 1981; Tsang, 1982). The growth of anchor ice implies interactions between ice and the sub- strate, and a marked change in the sedimentary environment. However, while the literature contains numerous observations that imply sediment transport, no studies have been conducted on the effects of anchor ice growth on sediment dynamics and bedforms. Underwater ice is the general term for ice formed in the supercooled water column.
    [Show full text]
  • Ing Cor!Paa L. T' Ron, L Ts Rrll.Cl Ostl Uct!Ir'p. Ar.'D Present. This L: A'so
    A~C MIEn4X Rvt3ENGR'!~Qual If N. Mvid Kirrcrcry >~q.ratrment of Mtcrbals Rierce and Encline~~ing viassachu~mtts Inst ' tute af Tiecharrlociy Caribxll+Ae p %3ssachusc~tts iltudiea of the charao terlSt iCS Of ice and rnacrOSCoplc computatians are useful. Ni ver- de to tnaat iori properties were f irst ca r r ied theless, a lot of progress has beer. n.aoe th' to tal.ucidate the behavior of glaciers, and it last several years, and Dr. pr.rtchard w 1' nas only been in the last few decades that inform us atoi.t. the oresent start Of affairs. i.hs properties of sea r.r e have been seri rnusly Sea ic behavior can also be approached studied. During the c:arly yearS oe yrorld 4'ar f'rom the poirit of view of rcateriril s - ropcr- the rani;e of British airCraft was inac'ne- tiis in which the characte.istics rrf the c- gus'te for protection of the North Atlarrtlc are related to its crystallirie structure, itS saa lanes and several Suggeetl'ons were made cor!paa l. t' ron, l ts rrll.cl Ostl uct!ir'p. ar.'d f:l uaing natural lce aS t.ernparary landing ir:fluence Of vari ous impurit leS whi.ch n ay be f'e 'da, lrowever, icebergs are notoriously present. This l: a'so a complex subject unstable and the prospect of. a landrng fie]d SlnCe iCe fsrma ln VariOuS WayS. ri'e -ar. flipping Over during an apprOach was nat very expect that the prof>ert.ic:s of sea cr whi cli =omfortablo.
    [Show full text]
  • Grease Ice in Basin-Scale Sea-Ice Ocean Models
    Annals of Glaciology 56(69) 2015 doi: 10.3189/2015AoG69A765 295 Grease ice in basin-scale sea-ice ocean models Lars H. SMEDSRUD,1 Torge MARTIN2 1Geophysical Institute, University of Bergen and Bjerknes Centre for Climate Research, Bergen, Norway E-mail: [email protected] 2GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany ABSTRACT. The first stage of sea-ice formation is often grease ice, a mixture of sea water and frazil ice crystals. Over time, grease ice typically congeals first to pancake ice floes and then to a solid sea-ice cover. Grease ice is commonly not explicitly simulated in basin-scale sea-ice ocean models, though it affects oceanic heat loss and ice growth and is expected to play a greater role in a more seasonally ice- covered Arctic Ocean. We present an approach to simulate the grease-ice layer with, as basic properties, the surface being at the freezing point, a frazil ice volume fraction of 25%, and a negligible change in the surface heat flux compared to open water. The latter governs grease-ice production, and a gradual transition to solid sea ice follows, with �50% of the grease ice solidifying within 24 hours. The new parameterization delays lead closing by solid ice formation, enhances oceanic heat loss in fall and winter, and produces a grease-ice layer that is variable in space and time. Results indicate a 10– 30% increase in mean winter Arctic Ocean heat loss compared to a standard simulation, with instant lead closing leading to significantly enhanced ice growth. KEYWORDS: atmosphere/ice/ocean interactions, crystal growth, polar and subpolar oceans, sea ice, sea- ice growth and decay 1.
    [Show full text]