Initially, the Committee's Work Focused on the Hydraulic Aspects of River Ice
Total Page:16
File Type:pdf, Size:1020Kb

Load more
Recommended publications
-
Theoretical Design of a Non-Cyclic Cooling System Using Pykrete As a Cooling Material and Considering the System As a Heat Exchanger
International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064 Index Copernicus Value (2013): 6.14 | Impact Factor (2015): 6.391 Theoretical Design of a Non-Cyclic Cooling System using Pykrete as a Cooling Material and Considering the System as a Heat Exchanger Divyashree Deore1, Sarthak Sharma2 B.E. Mechanical Engineering, Sinhgad Academy of Engineering, Pune, Maharashtra, India Abstract: A non-cyclic cooling unit was theoretically designed with supply of air similar to that of commercially available A.C. unit producing one ton of refrigeration. The minimum temperature for the design was considered to be 16℃. The element used for cooling the air is Pykrete. The various stable temperatures of Pykrete were experimentally found. Also, the cooling capacity of designed unit was found theoretically. The working principle of this system is similar to that of Thermal Energy Storage system. The calculations were carried out considering this system would act as a heat exchanger. Keywords: Non-Cyclic Cooling System, Pykrete, Stable Surface temperatures, Thermal Energy Storage System, Heat Exchanger 1. Introduction many months later, at individual building, multiuser building, district, town or even regional scale depending on In this method Pykrete is used for keeping the space at the specific technology. As examples: energy demand can be temperature below the surrounding temperature. Pykrete is a balanced between day time and night time; summer heat frozen composite material made of approximately 14 percent from solar collectors can be stored inter-seasonally for use in sawdust or some other form of wood pulp (such as paper) winter; and cold obtained from winter air can be provided and 86 percent ice by weight (6 to 1 by weight). -
Remote Sensing of Sea Ice
Remote Sensing of Sea Ice Peter Lemke Alfred Wegener Institute for Polar and Marine Research Bremerhaven Institute for Environmental Physics University of Bremen Contents 1. Ice and climate 2. Sea Ice Properties 3. Remote Sensing Techniques Contents 1. Ice and climate 2. Sea Ice Properties 3. Remote Sensing Techniques The Cryosphere Area Volume Volume [106 km2] [106 km3] [relativ] Ice Sheets 14.8 28.8 600 Ice Shelves 1.4 0.5 10 Sea Ice 23.0 0.05 1 Snow 45.0 0.0025 0.05 Climate System vHigh albedo vLatent heat vPlastic material Role of Ice in Climate v Impact on surface energy balance (global sink) ! Atmospheric circulation ! Oceanic circulation ! Polar amplification v Impact on gas exchange between the atmosphere and Earth’s surface v Impact on water cycle, water supply v Impact on sea level (ice mass imbalance) v Defines boundary conditions for ecosystems Role of Ice in Climate v Polar amplification in CO2 warming scenarios (surface energy balance; temperature – ice albedo feedback) IPCC, 2007 Role of Ice in Climate Polar amplification GFDL model 12 IPCC AR4 models Warming from CO2 doubling with Warming at CO2 doubling (years fixed albedo (FA) and with surface 61-80) (Winton, 2006) albedo feedback included (VA) (Hall, 2004) Contents 1. Ice and climate 2. Sea Ice Properties 3. Remote Sensing Techniques Pancake Ice Pancake Ice Old Pancake Ice First Year Ice Pressure Ridges Pressure Ridges New Ice Formation in Leads New Ice Formation in Leads New Ice Formation in Leads Melt Ponds on Arctic Sea Ice Melt ponds in the Arctic 150 m Sediment -
East Antarctic Sea Ice in Spring: Spectral Albedo of Snow, Nilas, Frost Flowers and Slush, and Light-Absorbing Impurities in Snow
Annals of Glaciology 56(69) 2015 doi: 10.3189/2015AoG69A574 53 East Antarctic sea ice in spring: spectral albedo of snow, nilas, frost flowers and slush, and light-absorbing impurities in snow Maria C. ZATKO, Stephen G. WARREN Department of Atmospheric Sciences, University of Washington, Seattle, WA, USA E-mail: [email protected] ABSTRACT. Spectral albedos of open water, nilas, nilas with frost flowers, slush, and first-year ice with both thin and thick snow cover were measured in the East Antarctic sea-ice zone during the Sea Ice Physics and Ecosystems eXperiment II (SIPEX II) from September to November 2012, near 658 S, 1208 E. Albedo was measured across the ultraviolet (UV), visible and near-infrared (nIR) wavelengths, augmenting a dataset from prior Antarctic expeditions with spectral coverage extended to longer wavelengths, and with measurement of slush and frost flowers, which had not been encountered on the prior expeditions. At visible and UV wavelengths, the albedo depends on the thickness of snow or ice; in the nIR the albedo is determined by the specific surface area. The growth of frost flowers causes the nilas albedo to increase by 0.2±0.3 in the UV and visible wavelengths. The spectral albedos are integrated over wavelength to obtain broadband albedos for wavelength bands commonly used in climate models. The albedo spectrum for deep snow on first-year sea ice shows no evidence of light- absorbing particulate impurities (LAI), such as black carbon (BC) or organics, which is consistent with the extremely small quantities of LAI found by filtering snow meltwater. -
Lecture 4: OCEANS (Outline)
LectureLecture 44 :: OCEANSOCEANS (Outline)(Outline) Basic Structures and Dynamics Ekman transport Geostrophic currents Surface Ocean Circulation Subtropicl gyre Boundary current Deep Ocean Circulation Thermohaline conveyor belt ESS200A Prof. Jin -Yi Yu BasicBasic OceanOcean StructuresStructures Warm up by sunlight! Upper Ocean (~100 m) Shallow, warm upper layer where light is abundant and where most marine life can be found. Deep Ocean Cold, dark, deep ocean where plenty supplies of nutrients and carbon exist. ESS200A No sunlight! Prof. Jin -Yi Yu BasicBasic OceanOcean CurrentCurrent SystemsSystems Upper Ocean surface circulation Deep Ocean deep ocean circulation ESS200A (from “Is The Temperature Rising?”) Prof. Jin -Yi Yu TheThe StateState ofof OceansOceans Temperature warm on the upper ocean, cold in the deeper ocean. Salinity variations determined by evaporation, precipitation, sea-ice formation and melt, and river runoff. Density small in the upper ocean, large in the deeper ocean. ESS200A Prof. Jin -Yi Yu PotentialPotential TemperatureTemperature Potential temperature is very close to temperature in the ocean. The average temperature of the world ocean is about 3.6°C. ESS200A (from Global Physical Climatology ) Prof. Jin -Yi Yu SalinitySalinity E < P Sea-ice formation and melting E > P Salinity is the mass of dissolved salts in a kilogram of seawater. Unit: ‰ (part per thousand; per mil). The average salinity of the world ocean is 34.7‰. Four major factors that affect salinity: evaporation, precipitation, inflow of river water, and sea-ice formation and melting. (from Global Physical Climatology ) ESS200A Prof. Jin -Yi Yu Low density due to absorption of solar energy near the surface. DensityDensity Seawater is almost incompressible, so the density of seawater is always very close to 1000 kg/m 3. -
Interannual Variability in Transpolar Drift Ice Thickness and Potential Impact of Atlantification
https://doi.org/10.5194/tc-2020-305 Preprint. Discussion started: 22 October 2020 c Author(s) 2020. CC BY 4.0 License. Interannual variability in Transpolar Drift ice thickness and potential impact of Atlantification H. Jakob Belter1, Thomas Krumpen1, Luisa von Albedyll1, Tatiana A. Alekseeva2, Sergei V. Frolov2, Stefan Hendricks1, Andreas Herber1, Igor Polyakov3,4,5, Ian Raphael6, Robert Ricker1, Sergei S. Serovetnikov2, Melinda Webster7, and Christian Haas1 1Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany 2Arctic and Antarctic Research Institute, St. Petersburg, Russian Federation 3International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, US 4College of Natural Science and Mathematics, University of Alaska Fairbanks, Fairbanks, US 5Finnish Meteorological Institute, Helsinki, Finland 6Thayer School of Engineering at Dartmouth College, Hanover, US 7Geophysical Institute, University of Alaska Fairbanks, Fairbanks, US Correspondence: H. Jakob Belter ([email protected]) Abstract. Changes in Arctic sea ice thickness are the result of complex interactions of the dynamic and variable ice cover with atmosphere and ocean. Most of the sea ice exits the Arctic Ocean through Fram Strait, which is why long-term measurements of ice thickness at the end of the Transpolar Drift provide insight into the integrated signals of thermodynamic and dynamic influences along the pathways of Arctic sea ice. We present an updated time series of extensive ice thickness surveys carried 5 out at the end of the Transpolar Drift between 2001 and 2020. Overall, we see a more than 20% thinning of modal ice thickness since 2001. A comparison with first preliminary results from the international Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) shows that the modal summer thickness of the MOSAiC floe and its wider vicinity are consistent with measurements from previous years. -
© Cambridge University Press Cambridge
Cambridge University Press 978-0-521-80620-6 - Creep and Fracture of Ice Erland M. Schulson and Paul Duval Index More information Index 100-year wave force, 336 friction and fracture, 289, 376 60° dislocations, 17, 82, 88 indentation failure, 345 microstructure, 45, 70, 237, 255, 273 abrasion, 337 multiscale fracture and frictional accommodation processes of basal slip, 165 sliding, 386 acoustic emission, 78, 90, 108 nested envelopes, 377 across-column cleavage cracks, 278 pressure–area relationship, 349, 352 across-column confinement, 282 S2 growth texture, 246, 273 across-column cracks, 282, 306, SHEBA faults, 371 across-column loading, 275 SHEBA stress states, 377 across-column strength, 246, 249, 275 Arctic Ocean, 1, 45, 190, 361 activation energy, 71, 84, 95, 111, 118, 131 aspect ratio, 344 activation volume, 114, 182 atmospheric ice, 219, 221, 241, 243 activity of pyramidal slip systems, 158 atmospheric icing, 31 activity of slip systems, 168 atmospheric impurities, 113 adiabatic heating, 291, 348 atomic packing factor, 9 adiabatic softening, 291 audible report, 240 affine self-consistent model, 160 avalanches, 206 air bubbles, 38 air-hydrate crystals, 37 bands, 89 albedo, 363 basal activity, 162 aligned first-year sea ice, 246 basal dislocations, 77 along-column confinement, 282 basal planes, 214, along-column confining stress, 282, basal screw dislocations, 77, 87 along-column strength, 244, 275 basal shear bands, 163 ammonia dihydrate, 181 basal slip, 18, 77, 127, 228 ammonia–water system, 186 basal slip lines, 77 amorphous forms -
Snow Removal and Ice Control. Proceedings of a Conference Gold, L
NRC Publications Archive Archives des publications du CNRC Snow Removal and Ice Control. Proceedings of a Conference Gold, L. W.; Williams, G. P. For the publisher’s version, please access the DOI link below./ Pour consulter la version de l’éditeur, utilisez le lien DOI ci-dessous. Publisher’s version / Version de l'éditeur: https://doi.org/10.4224/40001167 Technical Memorandum (National Research Council of Canada. Associate Committee on Soil and Snow Mechanics), 1964-02-17 NRC Publications Archive Record / Notice des Archives des publications du CNRC : https://nrc-publications.canada.ca/eng/view/object/?id=8f163de6-fe2d-4138-9c00-52a914883cdd https://publications-cnrc.canada.ca/fra/voir/objet/?id=8f163de6-fe2d-4138-9c00-52a914883cdd 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]. -
Nanomaterials Analysis and Standards
National Institute of Standards and Technology –Physical Measur –Physical Technology and Standards of Institute National Nanomaterials Analysis and Standards Michael T. Postek, Dianne L. Poster, NIST, Mark Driscoll, SUNY, Syracuse, Jay LaVerne, University of Notre Dame Mohamad Al-Sheikhly, University of Maryland ement Laboratory ement National Institute of Standards and Technology –Physical Measur –Physical Technology and Standards of Institute National National Institute of Standards and Technology • Welcome to NIST • NIST is the U.S. National Metrology Institute (NMI) • Research projects in advanced manufacturing (broadly defined), nanotechnology, nanomaterials, ionizing radiation and the necessary measurements (metrology) and standards are found all across NIST • Leverages the knowledge gained from work on other measurement problems, materials and structures Gaithersburg, MD – For example: Semiconductor metrology » Semiconductor companies most demanding over the last few years – measuring ever-shrinking structures ement Laboratory ement » Nanotechnology natural fit • Significant need for development of both advanced, basic (research/laboratory), and manufacturing (applied/production) measurement science Boulder, CO National Institute of Standards and Technology –Physical Measur –Physical Technology and Standards of Institute National Metrology: The science of measurement; a system of measures “When you can measure what you are speaking about, you know something about it. But when you cannot measure it, your knowledge is of a meager and unsatisfactory kind. It may be the beginning of knowledge, but you have scarcely advanced to the stage of science.” William Thomson, Lord Kelvin 1824 - 1907 In order to measure a quantity accurately, it is necessary to fully study and understand the measurement process itself ement Laboratory ement – may require multiple disciplines NIST works closely with scientists and industry to develop the Nation’s metrology infrastructure necessary for scientific, technical, and economic advances. -
Understanding Earth's Cold Regions
National Aeronautics and Space Administration Proposed NASA–ISRO SAR Mission Understanding Earth’s Cold Regions NISAR will measure changes in glacier and ice sheet motion, sea ice, and permafrost to determine how global climate and ice masses interrelate and how melting of land ice raises sea level. Impacts of Earth’s Remote Ice Perhaps you imagine the polar ice sheets as icy white blankets at the Snow Cover ends of the Earth, static and majestic, but far removed from your daily life. In reality, these areas are among the Sea most dynamic and rapidly changing Ice Ice Shelf places on Earth, where wind and Ice Sheet currents move ice over the seas, Glaciers and the forces of gravity disgorge Sea huge icebergs to the ocean. These Level Rise distant changes have very real local consequences of climate feedbacks Lake and Frozen and rising sea level. River Ice Ground Assessing Society’s Exposure to Diminishing Ice ice cover is decreasing drastically and may vanish entirely within the next decades. The loss of sea ice cover will have a For over a hundred years, scientists have considered diminishing profound effect on life, climate, and commercial activities in the glaciers and sea ice to be an early indicator of climate change. Arctic, while the loss of land ice will impact an important source At the same time, ice sheets and glaciers are already melting of water for millions of people. Collectively, these effects mean fast enough to be the largest contributors to sea level rise, with that despite its remote location, changes in ice have global a potential to raise sea level by several tens of centimeters or economic and health implications as climate changes. -
Crusty Alga Uncovers Sea-Ice Loss That Inhibits COX-2
Selections from the RESEARCH HIGHLIGHTS scientific literature PHARMACOLOGY Painkiller kills the bad effects of pot Marijuana’s undesirable effects NICK CALOYIANIS on the brain can be overcome by using painkillers similar to ibuprofen, at least in mice. Chu Chen and his colleagues at Louisiana State University Health Sciences Center in New Orleans treated mice with THC, marijuana’s main active ingredient. They found that THC impaired the animals’ memory and the efficiency of their neuronal signalling, probably by stimulating the enzyme COX-2. The authors reversed these negative effects — and were able to maintain marijuana’s benefits, such as reducing CLIMATE SCIENCES neurodegeneration — when they also treated the mice with a drug, similar to ibuprofen, Crusty alga uncovers sea-ice loss that inhibits COX-2. The authors suggest that the Like tree rings, layers of growth in a long-lived marine alga Clathromorphum compactum benefits of medical marijuana Arctic alga may preserve a temperature record (pictured). It can live for hundreds of years and could be enhanced with the use of past climate. Specimens from the Canadian builds a fresh layer of crust each year. of such inhibitors. Arctic indicate that sea-ice cover has shrunk The thickness of each layer, and the ratio of Cell 155, 1154–1165 (2013) drastically in the past 150 years — to the lowest magnesium to calcium within it, are linked to levels in the 646 years of the algal record. water temperature and the amount of sunlight PALAEOECOLOGY Satellite records of the Arctic’s shrinking the organism receives. The discovery suggests sea-ice cover date back only to the late 1970s. -
Article Sources and Dynamics, Other Seasons (Ducklow Et Al., 2015; Kim Et Al., 2015, 2019)
Biogeosciences, 16, 2683–2691, 2019 https://doi.org/10.5194/bg-16-2683-2019 © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License. Collection of large benthic invertebrates in sediment traps in the Amundsen Sea, Antarctica Minkyoung Kim1, Eun Jin Yang2, Hyung Jeek Kim3, Dongseon Kim3, Tae-Wan Kim2, Hyoung Sul La2, SangHoon Lee2, and Jeomshik Hwang1 1School of Earth and Environmental Sciences/Research Institute of Oceanography, Seoul National University, Seoul, 08826, South Korea 2Korea Polar Research Institute, Incheon, 21990, South Korea 3Korea Institute of Ocean Science and Technology, Busan, 49111, South Korea Correspondence: Jeomshik Hwang ([email protected]) Received: 18 February 2019 – Discussion started: 6 March 2019 Revised: 4 June 2019 – Accepted: 18 June 2019 – Published: 11 July 2019 Abstract. To study sinking particle sources and dynamics, other seasons (Ducklow et al., 2015; Kim et al., 2015, 2019). sediment traps were deployed at three sites in the Amund- Biogeochemical processes related to biological pump in the sen Sea for 1 year from February–March 2012 and at one Amundsen Sea have been investigated by recent field cam- site from February 2016 to February 2018. Unexpectedly, paigns (Arrigo and Alderkamp, 2012; Yager et al., 2012; large benthic invertebrates were found in three sediment traps Meredith et al., 2016; Lee et al., 2017). deployed 130–567 m above the sea floor. The organisms in- Sediment traps were deployed in the Amundsen Sea to cluded long and slender worms, a sea urchin, and juvenile study sinking material flux and composition. Sampling oc- scallops of varying sizes. -
Can Sea Water Freeze?
Can Sea Water Freeze? Unit: Salinity Patterns & the Water Cycle l Time Required: Four 45 min. class period l Grade Level: Middle l Content Standard: NSES Physical Science, properties and changes of properties in matter Ocean Literacy Principle 1e: Most of Earth's water (97%) is in the ocean. Seawater has unique properties: it is saline, its freezing point is slightly lower than fresh water, its density is slightly higher, its electrical conductivity is much higher, and it is slightly basic. Big Idea: Salt causes water to freeze at a lower temperature. Sea ice forms only under very cold conditions (e.g., near Earth’s poles) because of its salinity (i.e., presence of dissolved salt). Key Concepts: • Dissolving any substance in pure water raises or lowers the freezing and boiling point. • When water freezes - goes from the liquid state to the solid state - its molecules go from a disorganized state to an organized state. • When water freezes to a solid, molecular motion slows down enough that the molecules become permanently fixed in an orderly arrangement called a crystal. • The individual particles that make up salt (known as ions) arrange themselves around the water molecules. In doing so, they shield the water molecules from interactions among themselves, making it less likely that they will find each other and form ice. • The water molecules have to be slowed down even more in the presence of salt in order to form a solid. So you have to go to a lower temperature in order to freeze water that contains salt. • Salt is excluded in the formation of ice; therefore ice made from salt water is essentially salt-free.