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1
Hamré, Moa. "Förutsättningar för jökellopp vid Fox Glacier, Nya Zeeland". Thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-71989.
Testo completoAbstract (sommario):
A great number of tourists visits each day the Fox Glacier in New Zealand and are subjected todangers such as jökulhlaups. This phenomena can occur suddenly and in a destructive way when abuilt up of water suddenly bursts and releases large amounts of water. This is well known to happen atthe near by Franz Josef Glacier which has similar settings to Fox Glacier, but sparse previous researchon the subject indicates different results of whether jökulhlaups are present or not by Fox Glacier. Thisthesis therefore aims to study the conditions for jökulhlaups at the glacier. This is done by remotesensing and field observations of the sandur in the Fox Glacier Valley, qualitative interviews andliterature studies with a comparison with Franz Josef Glacier. The results shows that there has beenjökulhlaups from an ice dammed lateral lake which is also the most likable way for jökulhlaups tohappen again, although there are other potential ways for it to happen due to the large amount of heavyrain that this region gets.
2
H, Purdie. "Intra-annual variations in abaltion and surface velocity on the lower Fox Glacier, South Westland, New Zealand". Thesis, University of Canterbury. Geography, 2005. http://hdl.handle.net/10092/10451.
Testo completo
3
Hayes, D. G. "An Investigation of visitor behaviour in recreation and tourism settings: a case study of natural hazard management at the Glaciers, Westland National Park, New Zealand". Lincoln University, 2008. http://hdl.handle.net/10182/942.
Testo completoAbstract (sommario):
Visitor non-compliance with protective recommendations is a major problem faced by recreational managers within natural environments. Although many studies have been conducted on noncompliant visitor behaviour within natural resource areas, few attempts have been made to gain an understanding of the behaviour, or to understand the decision making process. This dissertation seeks to address this gap by exploring salient motivations behind noncompliant behaviour within a natural recreation setting. The study was conducted over the summer of 2007-2008 within the popular tourist attractions of Fox and Franz Josef glaciers, Westland National park, New Zealand. The Department of Conservation has a legal and increasingly a moral obligation to provide a level of service and ensure a high standard of visitor safety within lands it administers. However, despite its efforts, management actions are criticised as being ‘over cautious’, and consequently a large number of visitors choose to ignore hazard warnings communicated by management and cross safety barriers, placing themselves and others at considerable risk. Previous studies at the glaciers have identified a number of causes for visitor non-compliance, including situational factors and the adequacy of current visitor management procedures. Through a quantitative measure, and qualitative interview responses, study findings show that visitor compliance with protective recommendations was strongly influenced by a number of situational factors including the proximity of track end points from the glacier terminus; the visibility of other visitors beyond the roped barriers; modest hazard perceptions of visitors; estimated visitor age; time of day and weather conditions. Based on visitor interview responses, motives of non-compliance were further explored by classifying behaviour according to Gramann and Vander Stoep’s (1987) typologies of normative violations. It is identified, using Ajzen’s (1985; 1991) theory of planned behaviour, that non-compliance with protective recommendations at the glaciers is motivated by, (1) a ‘belief’ that the situation or resource encouraged it; (2), through a release of ‘social pressure’, because everyone else was going over; and (3), a ‘perceived facilitation of the behaviour’, in that there were no obvious consequences to self or others. Implications for management to control noncompliant behaviour are discussed in detail.
4
Espiner, Stephen. "The phenomenon of risk and its management in natural resource recreation and tourism settings : a case study of Fox and Franz Josef Glaciers, Westland National Park, New Zealand". Lincoln University, 2001. http://hdl.handle.net/10182/638.
Testo completoAbstract (sommario):
The significance of risk is growing in many Western societies, a phenomenon linked to increasing individualism, personal choice, and outcome uncertainty in multiple spheres of life. Despite being healthier and more physically protected from harm than any previous society, a serious concern for safety and risk control is emerging as a defining characteristic of modern social life. Within the context of a risk-averse society, this thesis investigates the nature and relevance of risk in natural resource recreation and tourism settings. Millions of people every day visit national parks and other protected areas around the world in which natural hazards inhere. Many visitors fail to recognise these hazards, creating moral, legal, and ethical issues for natural resource managers. People travel to national parks anticipating a degree of adventure, to escape routines, and to witness the grandeur of nature. Ironically, the very qualities that attract people to natural areas may also put them at risk. Managers of natural resource tourism and recreation areas in New Zealand are confronted with a paradox born out of visitor demand for nature experiences, a legal obligation to facilitate free access, and a growing social emphasis on health and safety. In particular, this study assesses the risk perceptions of visitors to the Fox and Franz Josef glaciers, popular tourist attractions on the West Coast of New Zealand's South Island, and explores the risk perceptions and beliefs of resource management agency staff. The study also investigates the issue of risk communication at these two sites, and the degree to which existing hazard messages are successful at encouraging appropriate visitor behaviour. Pictorial hazard warning signs are introduced to the sites and their effectiveness evaluated. The findings show that many visitors (especially international visitors) have relatively poor awareness of natural hazards, and behave in ways which potentially compromise physical safety. It is argued that perceptions and behaviour are a consequence of diverse individual and situational factors including limited knowledge of the sites, beliefs about management, poor comprehension of hazard warning signs, and freedom from the normative constraints of everyday life. In contrast to visitors, managers at the glacier sites consider the risks to be significant, and, potentially, severe. It is argued that managers' perceptions of risk are influenced by several important social and site-specific factors, including their own experiences of hazards at the glaciers, perceived legal and moral obligations, the organisational culture, and impressions of high societal expectation concerning safety. The situation is further complicated by the freedom of access principle in national parks, and increasing tourist demand for nature-based experiences. These factors governed beliefs about the subject of risk. This study identifies several dimensions of risk in nature-based recreation and tourism settings. Visitors are at risk of personal accident or injury at certain tourism attractions. Awareness of hazards is limited, visitor behaviour compromises safety, and existing communication strategies are only partially effective. Risk is also apparent in the agency responsible for management of outdoor recreation areas. Site managers perceive a risk in their failure to prevent visitors from harm, whereas senior managers identify risk as primarily financial, legal, and political. Collectively, these factors demonstrate that the phenomenon of risk is increasingly important in the tourism and recreation context, and has the potential to influence significantly both management and experience of protected natural areas in New Zealand.
5
Diaz, Melisa A. "Geochemistry of soils from the Shackleton Glacier region, Antarctica, and implications for glacial history, salt dynamics, and biogeography". The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595542667761355.
Testo completo
6
Foster, Lesley A. "Utilisation of remote sensing for the study of debris-covered glaciers : development and testing of techniques on Miage Glacier, Italian Alps". Thesis, University of Dundee, 2010. https://discovery.dundee.ac.uk/en/studentTheses/06d96169-df3b-49f0-b26c-f8f1ccc58e8d.
Testo completoAbstract (sommario):
An increase in the number of debris-covered glaciers and expansion of debris cover across many glaciers has been documented in many of the world’s major glacierised mountain ranges over the last 100 years. Debris cover has a profound impact on glacier mass balance with thick layers insulating the underlying ice and dramatically reducing ablation, while thin or patchy cover accelerates ablation through albedo reduction. Few debris-covered glaciers have been studied in comparison with ‘clean’ glaciers and their response to climatic change is uncertain. Remote sensing, integrated with field data, offers a powerful but as yet unrealised tool for studying and monitoring changes in debris-covered glaciers. Hence, this thesis focuses on two key aims: i) to test the utility of visible/near infrared satellite sensors, such as TERRA ASTER, for studying debris-covered glaciers; ii) to develop techniques to fully exploit the capability of these satellite sensors to extract useful information, and monitor changes over time. Research was focused on four interrelated studies at the Miage Glacier, in the Italian Alps. First, a new method of extracting debris-thickness patterns from ASTER thermal-band imagery was developed, based on a physical energy-balance model for a debris surface. The method was found to be more accurate than previous empirical approaches, when compared with field thickness measurements, and has the potential advantage of transferability to other sites. The high spatial variability of 2 m air temperature, which does not conform to a standard lapse rate, presents a difficulty for this approach and was identified as an important area for future research. Secondly, ASTER and Landsat TM data are used to map debris-cover extent and its change over time using several different methods. A number of problems were encountered in mapping debris extent including cloud cover and snow confusion, spatial resolution, and identifying the boundary between continuous and sporadic debris. Analysis of two images in late summer 1990 and 2004 revealed only a small up glacier increase in debris cover has occurred, confirming other work’s conclusions that the debris cover on Miage Glacier increased to its present extent prior to the 1990s. A third area of research used ASTER DEMs to monitor surface elevation changes of the Miage Glacier over time to update previous studies. Surface velocities on the glacier tongue were also calculated between 2004-2005 using feature-tracking of ASTER orthorectified visible band imagery and ASTER DEMs. However, ASTER DEMs were found to be rather poor for both applications due to large elevation errors in topographically rough parts of the glacier, which prevented a full analysis and comparison of results to previous surface elevation and velocity studies. Finally, the lithological units of the debris cover were mapped, based on the spectral differences of different rock types in the debris layer, providing information both on the location and concentration of different rock types on the surface. Therefore, the identification in the variation in emissivity throughout the glacier surface can be identified, which in turn has an impact upon calculated surface temperatures and ablation respectively. Overall, this research presents a significant contribution to understanding the impact of a debris layer on an alpine glacier, which is an area of key interest and current focus of many present glaciological studies. Since future glacial monitoring will increasingly have to consider supraglacial debris cover as a common occurrence, due to climate warming impacts of glacial retreat and permafrost melting. This contribution is achieved through the successful application of methods which utilise ASTER data to estimate debris thickness and debris extent, and the lithological mapping of debris cover. Therefore, the potential for incorporating these remote sensing techniques for debris-covered glaciers into current global glacier monitoring programs has been highlighted. However the utility of ASTER derived DEMs for surface elevation change analysis and surface velocity estimations in a study site of steep and varied terrain has been identified as questionable, due to issues of ASTER DEM accuracy in these regions.
7
Sagredo, Esteban A. "Glacier sensitivity along the Andes: implication for paleoclimatic reconstructions of the Little Ice Age". University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1342103681.
Testo completo
8
Fujita, Koji, e 耕史 藤田. "Effect of dust event timing on glacier runoff: sensitivity analysis for a Tibetan glacier". Wiley, 2007. http://hdl.handle.net/2237/11362.
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9
La, Frenierre Jeff David. "Assessing the Hydrologic Implications of Glacier Recession and the Potential for Water Resources Vulnerability at Volcan Chimborazo, Ecuador". The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1402593347.
Testo completo
10
Davis, Andrew D. (Andrew Donaldson). "Multi-parameter estimation in glacier models with adjoint and algorithmic differentiation". Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/72868.
Testo completoAbstract (sommario):
Thesis (S.M.)--Massachusetts Institute of Technology, Computation for Design and Optimization Program, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 75-77).
The cryosphere is comprised of about 33 million km³ of ice, which corresponds to 70 meters of global mean sea level equivalent [30]. Simulating continental ice masses, such as the Antarctic or Greenland Ice Sheets, requires computational models capturing abrupt changes in ice sheet dynamics, which are still poorly understood. Input parameters, such as basal drag and topography, have large effects on the applied stress and flow fields but whose direct observation is very difficult, if not impossible. Computational methods are designed to aid in the development of ice sheet models, ideally identifying the relative importance of each parameter and formulating inverse methods to infer uncertain parameters and thus constrain ice sheet flow. Efficient computation of the tangent linear and adjoint models give researchers easy access to model derivatives. The adjoint and tangent linear models enable efficient global sensitivity computation and parameter optimization on unknown or uncertain ice sheet properties, information used to identify model properties having large effects on sea-level. The adjoint equations are not always easily obtained analytically and often require discretizing additional PDE's. Algorithmic differentiation (AD) decomposes the model into a composite of elementary operations (+, -, *, /, etc ... ) and a source-to-source transformation generates code for the Jacobian and its transpose for each operations. Derivatives computed using the tangent linear and adjoint models, with code generated by AD, are applied to parameter estimation and sensitivity analysis of simple glacier models. AD is applied to two examples, equations describing changes in borehole temperature over time and instantaneous ice velocities. Borehole model predictions and data are compared to infer paleotemperatures, geothermal heat flux, and physical ice properties. Inversion using adjoint methods and AD increases the control space, allowing inference for all uncertain parameters. The sensitivities of ice velocities to basal friction and basal topography are compared. The basal topography has significantly larger sensitivities, suggesting it plays a larger role in flow dynamics and future work should seek to invert for this parameter.
by Andrew D. Davis.
S.M.
11
Jaña, Obregón Ricardo. "Digital elevation models and delineation of antarctic glaciers using stereo capabilities of ASTER satellite images steps on the way for a glacier monitoring on the Antarctic Peninsula /". [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:25-opus-37837.
Testo completo
12
Smith, Nita Jane. "An ASTER Digital Elevation Model (DEM) for the Darwin-Hatherton Glacial System, Antarctica". Thesis, University of Canterbury. Geography, 2007. http://hdl.handle.net/10092/1480.
Testo completoAbstract (sommario):
The Darwin-Hatherton glacial system is an outlet glacial system in the Transantarctic Mountains, Antarctica, which drains ice from the East Antarctic Ice Sheet into the Ross Ice Shelf. This research provides remotely sensed data that can be used in modeling research for the Darwin-Hatherton glacial system, which in turn can be used in mass balance research for the West Antarctic Ice Sheet. Two improved digital elevation models (DEM) are produced to cover the lower Darwin Glacier and to cover the upper Darwin and Hatherton Glaciers. The new improved DEMs are generated from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite data, with a resolution of 45 m. To produce the two final DEMs, multiple DEMs are firstly adjusted to remove systematic errors and are then stacked and averaged to increase the accuracy and produce the final two DEMs. For the lower Darwin Glacier, 5 DEMs were averaged and in the upper Darwin and Hatherton Glaciers, 6 DEMs were averaged. The accuracy is quantified by a remaining error of + 9 m for the lower Darwin Glacier DEM and + 37 m for the upper Darwin and Hatherton Glaciers DEM. This is a significant improvement from the existing 200 m resolution Radarsat Antarctic mapping project (RAMPv2) DEM which has a remaining error of + 138 m over the lower Darwin Glacier and + 152 m over the upper Darwin and Hatherton Glaciers. The accuracy is assessed by comparing the ASTER and RAMPv2 DEMs to highly accurate ice, cloud and land elevation satellite (ICESat) laser altimetry data. A 15 m resolution, true colour, orthorectified image is provided for the entire Darwin-Hatherton glacial system from ASTER satellite imagery. The DEMs used to orthorectify the ASTER satellite imagery are the two new 45 m resolution ASTER DEMs. Lastly feature tracking was explored as a method for measuring surface ice velocity. This research shows that feature tracking is unsuitable for the Darwin-Hatherton glacial system if using 15 m resolution satellite imagery over a 1 to 4 year time period.
13
Schoenenberger, Katherine R. "LITTLE ICE AGE CHRONOLOGY FOR CLASSEN AND GODLEY GLACIERS, MOUNT COOK NATIONAL PARK, NEW ZEALAND". University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin990634749.
Testo completo
14
Marshall, Gareth John. "The effectiveness of spaceborne synthetic aperture radar for glacier monitoring". Thesis, University of Cambridge, 1996. https://www.repository.cam.ac.uk/handle/1810/268042.
Testo completoAbstract (sommario):
This work examines the effectiveness of spaceborne synthetic aperture radar (SAR) for investigating seasonally variable glaciological parameters, in particular its ability to discriminate glacier surface facies in order to estimate glacier mass balance. A multitemporal C-band SAR dataset of Nordenskiold Land, Spitsbergen, acquired by the ERS-1 satellite, is used for the analysis, which focuses on mountain glaciers rather than ice sheets. Validating field measurements of ice and snowpack parameters were obtained contemporaneously with two SAR images, prior to and during the ablation season. A general model for the annual backscatter cycle from a sub-polar glacier is derived from SAR data of three glacierised areas. This model reveals two seasonal reversals in the relative magnitude of backscatter from the ice and wet-snow facies, principally through a 10 dB change in the latter; these reversals mark the start and end of the ablation season. It is shown that a combination of winter and summer SAR imagery is necessary to estimate the equilibriumline altitude of a sub-polar glacier. Topographic distortion is the major limiting factor regarding the utilisation of SAR data for studying mountainous glaciers. Existing theoretical models of radar backscatter from snow and ice are validated for three scenarios: glacier ice, dry snow overlying glacier ice, and wet snow, using the in situ measurements. In addition, temporal variations of ice and snowpack parameters observed during the field campaigns are used to predict short-term seasonal changes in backscatter, and to corroborate the model of annual backscatter. ERS-1 SAR data are compared to NIR Landsat TM data in separate analyses of data information content and temporal resolution; the optical data are found to be better for both facies discrimination and obtaining synoptic glaciological information in mountainous regions. However, the Spitsbergen cloud cover is such that useful TM data may not necessarily be acquired in a given year; consequently SAR is the better sensor for obtaining guaranteed synoptic mass balance data for use in climate change studies, or for studying short-term events like glacier surges. These conclusions are shown to apply to the entire European Arctic sector except East Greenland, where the two sensors have similar temporal resolutions. Data from both sensors were integrated to provide an estimation of the synoptic mass balance of Nordenskiold Land for 1991/92; the results, which indicate an overall slightly negative mass balance, demonstrate that elevation is the principal factor governing glacier net mass balance in the region.
15
Dierckx, Marie. "Marine ice rheology from deformation experiments of ice shelf samples using a pneumatic compression device: implications for ice shelf stability". Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209505.
Testo completoAbstract (sommario):
Antarctic ice shelves control the ice flux from the continent to the ocean. As such, they play a major role in the stability of the ice sheet and its potential contribution to sea level rise, especially in the context of global change. Below some of these ice shelves, marine ice can be found which is a product of the Deep Thermohaline Circulation. Due to its specific genetic process, marine ice has intrinsic physical (grain size, ice fabric, bubble content, ) and chemical (impurities, water stable isotopes) properties, that differ from those of 'meteoric ice' formed on the continent through snow metamorphism or 'sea ice' resulting from sea water freezing at the ocean-atmosphere surface. Until now however, the effect of these specific properties on marine ice rheology is still very poorly understood.The principal objective being to include realistic mechanical parameters for marine ice in ice shelf flow models, uniaxial compression experiments have been performed on various types of marine ice samples. Technical developments are an important component of this thesis has they were necessary to equip the laboratory with the appropriate tools (pneumatic rig, automatic ice fabric data handling).
Results from experimental compression on isotropic marine ice show that it represents the higher boundary for meteoric ice viscosity throughout the whole temperature range, thereby validating Cuffey and Paterson's relationship with an enhancement factor equals to 1.
Marine ice is however often quite anisotropic, showing elongated crystals and wide single maximum fabric, that should impact its mechanical properties. Experiments on pre-oriented marine ice samples have therefore been carried out combining the study of epsilon_{oct} vs. tau_{oct} with a thorough analysis of microstructural data 'before' and 'after' the experiment.
Depending on the orientation of the sample in the applied stress field and on the intensity of the latter, anisotropic marine ice can be harder or softer than its isotropic counterpart, with n=4 often observed in Glen's flow law. Associating the experimental geometrical settings to potential natural equivalent, results suggest that anisotropic marine ice would strengthen ice shelf flow in most areas (for a same given temperature), apart from suturing areas between individual ice streams as they merge to form the ice shelf, where it could become weaker than meteoric ice in certain circumstances.
Finally, preliminary sensitivity studies, using a simple ice shelf model with our experimental parameters of Glen's flow law have allowed us to discuss the potential impact of rift location, rift size and thermal regime in the ice shelf behavior.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
16
Noll, Christian John. "A geological framework for temporal sedimentary dynamics". [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2354.
Testo completo
17
Rose, Kathryn Clare. "A wireless multi-sensor subglacial probe for investigating the deforming glacier bed". Thesis, University of Southampton, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485440.
Testo completoAbstract (sommario):
The mechanisms that control glacier dynamics and fast ice stream flow are still poorly understood, largely due to the inaccessibility of the subglacial environment. One of the ways to improve on current investigations is to broaden the methods used to monitor the subglacial environment. An autonomous multi-sensor wireless probe was developed for use within an Environmental Sensor Network at Briksdalsbreen, Norway. Probes were deployed at the base of boreholes, measuring temperature, pressure, resistance (a proxy for conductivity), case strain, and tilt, six times a day. The probes used radio_communications to....transfer data to a base station at the glacier surface. The data was then sent to a reference station, which uploaded it onto the internet on a daily basis. In excess of a year's worth of data was obtained from several probes, deployed between 2004-2006. Readings of case strain and tilt indicated when the probes had become incorporated into the deforming bed. A reduction in sensor activity was displayed as the glacier changed from a summer to a winter regime. In the following spring, the sensors showed an increase in activity, particularly in water pressure. An Emergent Spring Event was recorded in February, followed by the actual Spring Event. This marked a transition to summer conditions within the glacier's hydrological system. Sliding was the dominant mechanism ofbasal motion during this time. In the summer, the probes began to rotate as the dominant form of basal motion transferred from sliding to till deformation. The movement of the probes was in keeping with the Taylor (1923) mechanism of clast rotation. Sedimentological analyses under the scanning electron microscope presented a relatively simple model for grain erosion within the deforming bed. Erosion occurs within a continuum whereby processes of both fracture and abrasion combine, generating intermediate grain forms. The style of deformation experienced is controlled by the nature of the bedrock and the overall strain imposed on the till. At Briksdalsbreen there was good evidence for erosion, but little evidence for the production of a significant silt component. This investigation demonstrates the potential for the use ofESNs within glacial environments. The probes provide a successful means by which the properties of and processes operating within the subglacial environment can be assessed over broad temporal and spatial scales. For the first time, activity was recorded within the subglacial environment much earlier than previously expected (January) and the spring event within unconnected regions of the bed was monitored and characterised. The records produced highlighted the complexity of hydro-mechanical interactions and the need for further study to constrain these processes. The probes also provided the first natural records of in situ clast rotation from within the deforming bed. This movement may have implications for models of clast rotation, the identification and classification of sediments, and models of grain interactions on the micro-scale.
18
Sunnegårdh, Sandra, e Thea Svensson. "Touch Glaciem : The Touch Screen for Soft Ice Machines". Thesis, KTH, Maskinkonstruktion (Inst.), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-176628.
Testo completoAbstract (sommario):
The Chinese company Ocean Power manufactures and exports soft ice cream machines to companies worldwide. Their machines have high functionality and robust design that enables a low-cost manufacturing. All machines have a control panel where settings of the machine and the ice cream can be ranged. The control panel is at present designed in accordance with an old indigenous design tradition. With increasing international influence and contact, the need of functionality and design is changing. To stay competitive Ocean Power requests a change and an improvement of the control panel. The device needs to be intuitive and more attractive to the western as well as the domestic market. The purpose of this Bachelor Thesis has therefore been to develop a new, modern, userfriendly control panel that takes both cognitive and visual ergonomics into consideration. In order to make the control panel more intuitive and user-friendly, cognitive and visual ergonomics were studied. Different design theories and rules of how a control panels should be designed were taken into consideration. After exhaustive observations on Ocean Powers machines and an interview with Richard Cederwall, former employee of Ocean Power, a brainstorming session took place. The project members came up with various suggestions on the new control panel and its design. A returning theme in all the proposals was simplicity and intuitive symbols. A hierarchy map was then developed in order to group the machines functions into logical sub categories. During the projects development phase, it was decided that the new control panel should be a touch screen. This would allow a more flexible interface design, as well as give the ice cream machine an uplifting look and a feeling of exclusivity. To show what the touch screen with its interface, functions and graphics are meant to look like, a prototype was developed. The prototype is programmed for Android operating systems and will be demonstrated on an Android touch pad. This gives the viewer a realistic idea of what the interface could look like and how it would work.Det kinesiska företaget Ocean Power tillverkar och exporterar glassmaskiner till företag världen över. Deras maskiner har hög funktionalitet och robust design som möjliggör en billig tillverkning. Alla glassmaskiner har en kontrollpanel där inställningar av maskinen och dess mjukglass kan göras. Kontrollpanelen är idag utformad i enlighet med en äldre inhemsk designtradition. Med ökad internationell påverkan och med ökad internationell kontakt förändras kundernas krav på funktionalitet och design. Ocean Power ser därför en nödvändighet att förändra och förbättra kontrollpanelen till en mer intuitiv och attraktiv panel som attraherar även den västerländska marknaden. Syftet med detta kandidatarbete har därför varit att ta fram en ny mer modern, användarvänlig kontrollpanel som tar hänsyn till både kognitiv och visuell ergonomi. För att göra panelen mer intuitiv och användarvänlig samlades mycket fakta kring kognitiv och visuell ergonomi in. Olika designteorier och regler för hur kontrollpaneler bör utformas studerades. Efter en intervju med Richard Cederwall, tidigare anställd på Ocean Power och efter att maskinerna studerats noggrant utfördes en brainstorming där projektgruppen tog fram olika förslag på kontrollpaneler. Ett genomgående tema i alla förslag var enkelhet och intuitiva symboler. Därefter togs en hierarkikarta fram för att på ett logiskt sätt gruppera de olika funktionerna i underkategorier. Under projektets utvecklingsfas beslutades att den nya kontrollpanelen skulle bestå av en touch screen. En touch screen möjliggör för en mer flexibel design av gränssnitt samt ger hela glassmaskinen ett lyft och får den att kännas mer exklusiv. För att visa hur den tänkta touch screenen med dess gränssnitt, funktioner och grafik är tänkt att se ut har en prototyp tagits fram. Prototypen programmerades för ett Android operativsystem för att sedan kunna testas på en Android touch pad. På det viset kan användaren få en realistisk bild av hur gränssnittet är tänkt att se ut och fungera.
19
Javan-Mashmool, Mandana. "Theoretical and experimental investigations for measuring interfacial bonding strength between ice and substrate". Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2005. http://theses.uqac.ca.
Testo completo
20
Khamis, Kieran. "Climate change and glacier retreat in the French Pyrénées : implications for Alpine river ecosystems". Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/4927/.
Testo completoAbstract (sommario):
Climate change disproportionately threatens alpine river ecosystems due to the strong connections between cryosphere, hydrology and physicochemical habitat. Our general understanding of how these systems will respond to warming is, however, based on conceptual models derived from studies undertaken at relatively small spatial scales. This research utilizes: (i) field data collected from five glacierized river basins in the French Pyrénées; (ii) field based experimentation; and (iii) climate/hydrological modelling, to improve understanding of alpine river ecosystem change. Despite a linear, harsh-begin, physicochemical habitat gradient running from high to low meltwater (snow and ice) contribution, observed benthic macroinvertebrate community level metrics were unimodal (i.e. mid-meltwater peak). Community assembly processes shifted from niche filtering/stochastic (trait convergence) at high meltwater sites, to limiting similarity/stochastic (trait divergence) at low meltwater sites. Benthic macroinvertebrate community structure, feeding interactions and body size spectra were altered when invertebrate predator range expansion was experimentally simulated. Empirical observation (space for time substitution) and statistical modelling both suggest an increase in reach scale diversity (alpha) is likely as glacier cover is lost. However, a reduction in habitat heterogeneity is likely to lead to biotic homogenization (reduced beta diversity) as a specialist high meltwater community is replaced by a more generalist community. The need to consolidate monitoring strategies is highlighted and functional trait profiles are suggested as useful bio-monitoring tools for detecting future change.
21
Smart, Martin James. "Deglaciation dynamics of the Feegletscher Nord, Switzerland : implications for glacio-fluvial sediment transfer". Thesis, University of Hertfordshire, 2015. http://hdl.handle.net/2299/17094.
Testo completoAbstract (sommario):
Understanding of the processes of sediment transfer within, and from, glaciated catchments is of fundamental importance in order to establish rates of sediment transfer and resultant landscape evolution. Rates of glacio-fluvial sediment transfer are strongly controlled by glacier meltwater runoff and the availability of sediments for entrainment. However, it is becoming apparent that recently deglaciated forefields can modify the patterns of suspended sediment transfer. Glacier shrinkage exposes areas of unstable glacigenic sediments that can be subject to reworking and redistribution, and, as these environments become ice-free, heightened levels of geomorphological activity (so-called 'paraglacial' activity) are also likely to have a significant impact on both sediment and water yields from deglaciating catchments. Consequently, questions are raised as to the impacts of deglaciation upon contemporary and future rates of suspended sediment transfer, and the resultant fluvial sediments loads and rates of landscape adjustment. Therefore, the aim of this research was to present an integrated study of how sediment transfer in a glaciated catchment functions during, and is responding to, deglaciation. A variety of techniques were employed to examine the hydrological functioning of an Alpine glacier, the Feegletscher Nord, Switzerland, and the resultant temporal and spatial patterns of sediment transfer in light of catchment hydrology, ablation processes and forefield geomorphology. Data was collected over two field campaigns in 2010 and 2012 to capture the inputs, throughputs and outputs of meltwater and sediment. This research found that patterns of sediment transfer were modified within the proglacial zone, reinforcing previous findings that the location of proglacial monitoring is important in determining the observed patterns of sediment transfer. These patterns of sediment transfer were attributed to variations in forefield sediment availability, which appeared to demonstrate marked spatial variability. This variability was hypothesised to be influenced by the geomorphological characteristics of the forefield, including rock fall debris that appeared to limit sediment availability, and glacigenic sediment deposits that enhanced the availability of in-channel and channel-marginal sediments. These findings suggest that the investigation of rates of sediment transfer and paraglacial sedimentation may be complicated in catchments that have experienced complex geomorphological responses to deglaciation. In addition, the investigation of sediment transfer processes and the development of a glacier runoff model enabled the exploration of future suspended sediment loads with progressive deglaciation and a changing climate. Suspended sediment loads were predicted to experience rapid declines until the end of the 21st Century due to reductions in meltwater runoff as glacier extent is reduced. However, it is suggested that uncertainties in future sediment availability limit the usefulness of such forecasts. Consequently, this research highlights how the understanding of both sedimentary and hydrological processes in glaciated catchments may be enhanced by consideration of the changes that can occur in these environments associated with glacier shrinkage and a changing climate.
22
Rootes, Camilla M. "The nature and use of trimlines for analysing 3-dimensional glacier change in rugged terrain". Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/22341/.
Testo completo
23
Araujo-Cabarcas, Juan Carlos. "Numerical methods for glacial isostatic adjustment models". Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-193856.
Testo completoAbstract (sommario):
Nordic countries experience post-glacial rebound, a movement where geographical contours slowly change elevation with respect to the mean sea level. The glacial isostatic adjustment (GIA) model aims to explain the phenomena, which combined with seismic data allows geoscientists to reconstruct elastic coefficients and viscosities of the Earth's lithosphere and upper mantle. The use of standard commercial codes are not adequate for GIA simulations and result in significant errors in the displacement field. This negative outcome suggests the development of GIA codes that include advection of pre-stress in the model. The problem set up consists on a solid 2D elastic layer under a flat Earth approximation, described by three different models suggested by current studies in geophysics. For space discretization the mixed finite element method (mFEM) is used and efficient preconditioners are built for the resulting algebraic system in saddle point form. A three level GMRES iterative solution strategy is proposed, based on Schur Complement preconditioners coupled with Multigrid techniques. The implementation is presented as a ready-to-use toolbox that easily deals with problem parameters, geometries, compressible and fully incompressible materials and provides higher accuracy for the displacement field compared with the previously existent codes. It also can be easily extended to 3D geometries and allows the implementation of a viscoelastic mantle. The code is written in C++ using the deal.II library designed for FEM, permitting the use of readily-made software packages, such as Trilinos that are straightforwardly parallelizable.
24
Trenbirth, Hazel Elizabeth. "Direct lichenometry in southern Norway : lichen growth rates, environmental controls and implications for lichenometric dating". Thesis, Swansea University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678291.
Testo completo
25
Dux, Andrew Martin. "Distribution and population characteristics of lake trout in Lake McDonald, Glacier National Park implications for suppression /". Thesis, Connect to this title online, 2005. http://etd.lib.montana.edu/etd/2005/dux/DuxA1205.pdf.
Testo completoAbstract (sommario):
Thesis (M.S.)--Montana State University--Bozeman, 2005.Title from PDF t.p. (viewed on Mar. 30, 2008). Chairperson, Graduate Committee: Christopher S. Guy. Includes bibliographical references (p. 67-76).
26
Wood, Chris, e Dan Smith. "Dendroglaciological Evidence for a Neoglacial Advance of the Saskatchewan Glacier, Banff National Park, Canadian Rocky Mountains". Tree-Ring Society, 2004. http://hdl.handle.net/10150/262633.
Testo completoAbstract (sommario):
Seventeen glacially sheared stumps in growth position and abundant detrital wood fragments were exposed by stream avulsion at the terminus of the Saskatchewan Glacier in 1999. The stumps lay buried beneath the glacier and over 5 m of glacial sediment until historical recession and stream incision exposed the 225- to 262-year-old stand of subalpine fir, Englemann spruce and whitebark pine trees. Crossdating and construction of two radiocarbon-controlled floating tree-ring chronologies showed that all the subfossil stumps and boles exposed at this location were killed during a Neoglacial advance of the Saskatchewan Glacier 2,910 ± 60 to 2,730 ± 60 ¹⁴C years B.P. These findings support the Peyto Advance as a regional glaciological response to changing mass balance conditions.
27
Fox, A. M. "A distributed, physically based snow melt and runoff model for alpine glaciers". Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599154.
Testo completoAbstract (sommario):
This thesis describes the development, testing and use of a distributed, physically based model of snow melt and runoff for alpine glaciers. A distributed version of a one-dimensional energy and mass balance snowpack model, SNTHERM, is coupled to a two-dimensional saturated flow model, MODFLOW, and is used to simulate meltwater production, vertical and lateral routing, storage and runoff across the temperate Haut Glacier d’Arolla, Switzerland at the beginning of the 2000 melt season. SNTHERM was first modified to incorporate an albedo scheme parameterised for this glacier, and to stimulate melt and runoff from glacier ice in additional to the seasonal snowpack. The performance of this 1-D model was tested against a suite of observations made on the glacier during spring 2000. It was found to reproduce observed rates of snowpack ablation and unsaturated meltwater movement through the snowpack well. The model was then used to investigate the relative contribution of the surface energy balance components to surface melt, and the delay in runoff and short-term storage of meltwater caused by unsaturated flow. A distributed version of SNTHERM was developed for use across the glacier. A digital elevation model (DEM) of the glacier surface and surrounding topography, together with data from a weather station located on the glacier, were used to calculate input variables of slope angle, aspect, shading and meteorological conditions across the glacier surface on a grid with a spatial resolution of 50 m. Initial snowpack depths and densities at the start of melt were determined from a snow survey conducted around the time of peak accumulation, with snow depth measurements interpolated onto a grid with the same resolution as the meteorological variables. SNTHERM was then run for each grid cell at an hourly resolution. Model performance was shown to be good when tested against repeat measurements of snow depth and albedo made along a glacier centreline stake network.
28
Davis, Andrew D. (Andrew Donaldson). "Prediction under uncertainty : from models for marine-terminating glaciers to Bayesian computation". Thesis, Massachusetts Institute of Technology, 2018. https://hdl.handle.net/1721.1/121812.
Testo completoAbstract (sommario):
Thesis: Ph. D. in Computational Science and Engineering, Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2018Cataloged from PDF version of thesis.
Includes bibliographical references (pages 255-266).
The polar ice sheets have enormous potential impact on future global mean sea level rise. Recent observations suggest they are losing mass to the ocean at an accelerated rate. Skillful prediction of the ice sheets' future mass loss remains difficult, however; observations of key variables are insufficient and physical processes are poorly understood. Even when a relatively accurate dynamical model is available, computational limitations make it difficult to characterize uncertainties associated with the model's predictions. To address this prediction challenge, this thesis presents complementary developments in glaciology and in Bayesian computation.
In particular, (i) we develop new models of marine-terminating glaciers whose dynamics are controlled by an extended set of physical processes and geometric constraints; and (ii) we develop new sampling algorithms to efficiently characterize selected marginals of a high-dimensional probability distribution describing uncertain parameters. The latter algorithms have broader utility in Bayesian modeling and inference with computationally intensive models. We begin by studying laterally confined ice streams that terminate in the ocean, where they may form floating ice shelves. Such marine-terminating outlet glaciers are the main conduits by which Greenland and Antarctica drain their ice mass into the ocean. Ice shelves play an important role in buttressing the grounded inland ice. The seaward ice flow is typically accompanied by acceleration and thinning. Increased thinning eventually leads to flotation of the ice supported by buoyant forces from the ocean.
The transition region from grounded to floating ice is referred to as the grounding line (or zone), and the mass transport across the grounding line as the output flux. Previous work by Weertman (1974) and Schoof (2007) considers laterally unconfined ice streams, showing that their output flux is a monotonically increasing function of the bedrock rock depth at the grounding line. This scenario leads to the marine ice sheet instability (MISI): retreating into deeper water increases the output flux, and retreat accelerates. Therefore, stable steady states cannot exist on downward sloping beds. We extend this analysis to laterally confined glaciers and investigate when side-wall drag is sufficient to stabilize glaciers on downward sloping beds. Additionally, we include a parameterization of sub-shelf melt. We find that, whereas lateral drag can stabilize glaciers that would otherwise be subject to the MISI, sub-shelf melt can destabilize them.
Our ultimate goal is to predict future ice sheet volume and to quantify its uncertainty. We do so in the Bayesian statistical setting, conditioning our prediction on available observations. Yet characterizing a posterior distribution-using, for example, Markov chain Monte Carlo (MCMC)-involves repeated evaluations of an ice stream model, which are prohibitively expensive. Furthermore, the model parameters that need to be inferred are high dimensional, even though we are primarily interested in a low dimensional quantity: the future ice volume. We address this computational challenge by developing new structure-exploiting Monte Carlo methods that combine marginalization with surrogate modeling. Given a high-dimensional (posterior) distribution on the model parameters, whose density evaluations are computationally intensive, we construct an MCMC chain that directly targets a particular low-dimensional marginal of interest. In general, the marginal density is not available analytically.
Instead, we can compute unbiased noisy estimates of this density. Our MCMC algorithm incrementally constructs a local regression approximation of the target marginal density using these estimates. Continual refinement of the approximation, as MCMC sampling proceeds, leads to an asymptotically exact characterization of the desired marginal distribution. Analysis of the bias-variance tradeoff guides an ideal refinement strategy that balances the decay rates of different components of the error. Our approach exploits regularity in the marginal density to significantly reduce computational expense relative to both full-dimensional and pseudo-marginal MCMC.
by Andrew D. Davis.
Ph. D. in Computational Science and Engineering
Ph.D.inComputationalScienceandEngineering Massachusetts Institute of Technology, Department of Aeronautics and Astronautics
29
Petrenko, Vasilii Victorovich. "A study of carbon-14 of paleoatmospheric methane for the last glacial termination from ancient glacial ice". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3291947.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of California, San Diego, 2008.Title from first page of PDF file (viewed March 18, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
30
Hekkers, Michael Leslie. "Climatic and Spatial Variations of Mount Rainier's Glaciers for the Last 12,000 Years". PDXScholar, 2010. https://pdxscholar.library.pdx.edu/open_access_etds/4951.
Testo completoAbstract (sommario):
Regional paleoclimatic proxies and current local climate variables and were analyzed to reconstruct paleoglaciers in an effort to assess glacier change On Mount Rainier. Despite the dry and generally warm conditions (sea surface temperatures (SST) -0.15°C to +1.8°C relative to current temperatures), the previously documented McNeeley II advance (10,900 - 9,950 cal yr B.P.) was likely produced by air temperature fluctuations. The average SST record and the terrestrial climate proxies show cooling temperatures with continued dryness between McNeeley II and the Burroughs Mountain advance (3,442 - 2,153 cal yr B.P.). The paleoclimate during the Burroughs Mountain advance was both cool and warm (SST temperatures -0.55°C to +0.5°C) and was the wettest of the Holocene.
A combination of statistical and deterministic equilibrium line altitude (ELA) models was used to produce Holocene ELAs between 1,735 -2,980 m. Glacial advances were predicted 10,990, 10,170, 9,260, 8,200, 6,490, 3,450 and 550 - 160 cal yr. B.P. Two glacier flow models were produced simultaneously to constrain glacial extent through the Holocene. Model I is based on current mass balance parameters and produced lengths for the Nisqually and Emmons glaciers 3.7 - 14.2 km and 4.2 - 17.1 km respectively. Glaciated area ranged from 26 to 327 km2. Model 2 is tuned to the Garda advance and produced lengths 2.6-10.6 km and 2.3-13.9 km. Glaciated area ranged from 11 to 303 km2. The first two advances were similar in elevation and GIS-modeled extent to McNeely II moraines. The following three advances were not detected in the geologic record. The 3,450 cal yr. B.P. advance was the largest of the late-Holocene (ELA 1,800 - 1,817 m) and was ~200 m lower than the geologic record. The ELAs of the Garda advance were modeled (1,944 - 1,983 m) and are similar to previous reconstructions. North-south spatial variations in glacial extent increase during periods of recession as the southern glaciers receive more ablation than northern glaciers.
Early humans could have accessed the alpine environments as high as 1,730-2,980 m. The early Holocene glacial extent allowed the highest (2,980 m) 11,150 cal yr. B.P. and lowest (1,730 m) 10,990 cal yr. B.P. alpine access. Glacial retreat (2,727 m 10,400 cal yr. B.P.) was followed by an advance (1,929 m 10,170 cal yr. B.P.) and another retreat (2,951 m 10,050 cal yr. B.P.). Ice gradually descended and limited access to 1,820 m 6,490 cal yr. B.P. Glacial extents remained largely unchanged until the historic era when paleohumans would have had access to alpine environments at 2,000 m.
31
Degenhardt, John Jerome. "A model for the development of a lobate alpine rock glacier in southwest Colorado, USA implications for water on Mars /". Texas A&M University, 2002. http://hdl.handle.net/1969/320.
Testo completo
32
Dhanasekaran, Deepananthan. "A Locally Adaptive Spatial Interpolation Technique for the Generation of High-Resolution DEMs". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306112037.
Testo completo
33
Sen, Gupta Avirup. "Improving the Physical Processes and Model Integration Functionality of an Energy Balance Model for Snow and Glacier Melt". DigitalCommons@USU, 2014. https://digitalcommons.usu.edu/etd/3875.
Testo completoAbstract (sommario):
The Hindu-Kush Himalayan region possesses a large resource of snow and ice, which acts as a freshwater reservoir for irrigation, domestic water consumption or hydroelectric power for billions of people in South Asia. Monitoring hydrologic resources in this region is challenging because of the difficulty of installing and maintaining a climate and hydrologic monitoring network, limited transportation and communication infrastructure and difficult access to glaciers. As a result of the high, rugged topographic relief, ground observations in the region are extremely sparse. Reanalysis data offer the potential to compensate for the data scarcity, which is a barrier in hydrological modeling and analysis for improving water resources management. Reanalysis weather data products integrate observations with atmospheric model physics to produce a spatially and temporally complete weather record in the post-satellite era. This dissertation creates an integrated hydrologic modeling system that tests whether streamflow prediction can be improved by taking advantage of the National Aeronautics and Space Administration (NASA) remote sensing and reanalysis weather data products in physically based energy balance snow melt and hydrologic models. This study also enhances the energy balance snowmelt model by adding capability to quantify glacier melt. The novelty of this integrated modeling tool resides in allowing the user to isolate various components of surface water inputs (rainfall, snow and glacier ice melt) in a cost-free, open source graphical-user interface-based system that can be used for government and institutional decision-making. Direct, physically based validation of this system is challenging due to the data scarcity in this region, but, to the extent possible, the model was validated through comparison to observed streamflow and to point measurements at locations in the United States having available data
34
Maier, Monika E. "Clark's Nutcracker Seed Harvest Patterns in Glacier National Park and a Novel Method for Monitoring Whitebark Pine Cones". DigitalCommons@USU, 2012. https://digitalcommons.usu.edu/etd/1275.
Testo completoAbstract (sommario):
Clark's Nutcracker (Nucifraga columbiana) is the primary seed disperser of whitebark pine (Pinus albicaulis), which is in decline throughout its range. There is concern that a decline in whitebark pine will lead to a subsequent decline in local populations of Clark's Nutcracker. Because natural regeneration depends on the presence of Clark's Nutcracker, the process of harvesting whitebark pine seeds needs to be fully understood. In addition, resource managers need a cost-effective method for monitoring nutcracker occurrence in whitebark pine stands during the seed harvest season. I visited eleven study sites in Glacier National Park, Montana, where I searched for Clark's Nutcracker and surveyed whitebark pine cones for seed harvesting scars, the presence of which indicated that nutcrackers harvested seeds. I documented cone use patterns of Clark's Nutcracker and the major cone predator, red squirrel (Tamiasciurus hudsonicus), at five sites. To identify factors that influence cone use, I ran a correlation analysis with nutcracker and red squirrel seed harvesting variables with physical, compositional, and whitebark pine-related factors. I found that nutcrackers harvested seed at every site that had cones available. Nutcrackers harvested seed from a greater proportion of whitebark pine cones in stands where they started intensively harvesting seeds earlier. Nutcrackers began intensively harvesting seeds earlier in stands with higher relative dominance of whitebark pine. Red squirrels depleted the cone source more rapidly in stands with greater whitebark pine mortality, and at one site depleted the cone source completely before nutcrackers began intensively harvesting seeds from that site. The results of this study suggest that Clark's Nutcracker will continue to harvest seeds even as whitebark pine declines, but the decline in whitebark pine may lead to decreased seed dispersal due to greater pre-dispersal cone predation by red squirrels. Finally, I evaluated direct and indirect monitoring methods to identify a cost-effective method to accurately monitor Clark's Nutcracker occurrence in whitebark pine stands during the seed harvest season. I found that surveying scars made by seed-harvesting nutcrackers on whitebark pine cones was the most accurate and economical method of monitoring Clark's Nutcracker occurrence in an area with a low population of Clark's Nutcracker.
35
Zhou, Hao Bevis Michael. "Layered cartesian half-space models for earth's elastic response to contemporary surface loading phenomena". Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1204657482.
Testo completo
36
Stroup, Justin Sirico. "Glacial Lake Ojibway, lacustrine stratigraphy and implications for drainage". Cincinnati, Ohio : University of Cincinnati, 2009. http://rave.ohiolink.edu/etdc/view.cgi?acc_num=ucin1243303456.
Testo completoAbstract (sommario):
Thesis (M.S.)--University of Cincinnati, 2009.Advisor: Thomas V. Lowell. Title from electronic thesis title page (viewed Aug. 18, 2009). Includes abstract. Keywords: Lake Ojibway; lacustrine; 8,200 year event; lake cores; XRF chemistry; stratigraphy; Laurentide; Ice proximal; varves; drainage; Canada. Includes bibliographical references.
37
Nicholson, Lindsey. "Modelling melt beneath supraglacial debris : implications for the climatic response of debris-covered glaciers". Thesis, University of St Andrews, 2005. http://hdl.handle.net/10023/10264.
Testo completoAbstract (sommario):
Understanding how debris-covered glaciers respond to climate is necessary in order to evaluate future water resources and glacier flood hazard potential, and to make sense of the glacier chronology in mountain regions, In order achieve this, it is necessary to improve the current understanding of how surface debris affects glacier ablation rate, and to develop methods by which the ablation of debris-covered glaciers can be predicted under various climatic scenarios. This thesis develops a numerical surface energy balance model that uses simple meteorological data to calculate melt beneath a debris layer of given thickness and thermal characteristics. Field data from three contrasting sites demonstrate that the assumptions made within the model concerning the thermal properties of supraglacial debris are valid during most ablation conditions and that model performance is considerably better than previous models. Model results indicate that the effect of debris on melt rate is highly dependent on meteorological conditions. Under colder climates, thin debris can accelerate ice melt by extending the ablation period at both diurnal and seasonal scales. However, in milder mid- summer conditions, even a very thin debris cover inhibits melt rate compared to that of exposed ice. The new melt model is applied to produce the first quantified ablation gradients for debris- covered glaciers, and to model the evolution of ice surfaces under a debris layer of variable thickness. Modelled ablation gradients are qualitatively similar to hypothetical ones outlined previously, and quantitatively similar to those measured in the field. The ablation gradients are used to explore the factors affecting the response of debris-covered glaciers to climate change. Beneath a debris layer of variable thickness, the melt model produced ablation topography, as observed in the field, which underwent topographic inversion over time in response to debris redistribution. Debris thickness variability was found to cause calculated ablation rate to increase compared to that calculated using a mean debris thickness by one to two orders of magnitude, suggesting that melt calculations made on the basis of spatially averaged debris thickness may be inaccurate.
38
Williams, Stephen Vincent. "Visual arctic navigation: techniques for autonomous agents in glacial environments". Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41135.
Testo completoAbstract (sommario):
Arctic regions are thought to be more sensitive to climate change fluctuations, making weather data from these regions more valuable for climate modeling. Scientists have expressed an interest in deploying a robotic sensor network in these areas, minimizing the exposure of human researchers to the harsh environment, while allowing dense, targeted data collection to commence. For any such robotic system to be successful, a certain set of base navigational functionality must be developed. Further, these navigational algorithms must rely on the types of low-cost sensors that would be viable for use in a multi-agent system. A set of vision-based processing techniques have been proposed, which augment current robotic technologies for use in glacial terrains. Specifically, algorithms for estimating terrain traversability, robot localization, and terrain reconstruction have been developed which use data collected exclusively from a single camera and other low-cost robotic sensors. For traversability assessment, a custom algorithm was developed that uses local scale surface texture to estimate the terrain slope. Additionally, a horizon line estimation system has been proposed that is capable of coping with low-contrast, ambiguous horizons. For localization, a monocular simultaneous localization and mapping (SLAM) filter has been fused with consumer-grade GPS measurements to produce full robot pose estimates that do not drift over long traverses. Finally, a terrain reconstruction methodology has been proposed that uses a Gaussian process framework to incorporate sparse SLAM landmarks with dense slope estimates to produce a single, consistent terrain model. These algorithms have been tested within a custom glacial terrain computer simulation and against multiple data sets acquired during glacial field trials. The results of these tests indicate that vision is a viable sensing modality for autonomous glacial robotics, despite the obvious challenges presented by low-contrast glacial scenery. The findings of this work are discussed within the context of the larger arctic sensor network project, and a direction for future work is recommended.
39
Loving, Jolene LaVal. "Physical mechanisms for climate variability during glacial and interglacial periods /". Diss., Digital Dissertations Database. Restricted to UC campuses, 2004. http://uclibs.org/PID/11984.
Testo completo
40
Stutz, James Edward II. "Reconstruction of LGM and Post LGM Glacial Environment of McMurdo Sound: Implications for Ice Dynamics, Depositional Systems and Glacial Isostatic Adjustment". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1324595182.
Testo completo
41
Favey, Etienne. "Investigation and improvement of airborne laser scanning technique for monitoring surface elevation changes of glaciers /". Zürich, 2000. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=14045.
Testo completo
42
Chase, Geneva Erin. "Late-Glacial Climate as Inferred fom Chironomid Assemblages in Lake Sediments from Aroostook County, Northeastern Maine". Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/ChaseGE2004.pdf.
Testo completo
43
Barrett, Brian Edward. "Ground penetrating radar techniques for quantifying water distribution in glacial ice". Thesis, University of Leeds, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441173.
Testo completo
44
Dix, Justin K. "The use of high resolution geophysics for the investigation of submerged palaeo-glaciomarine environments". Thesis, University of St Andrews, 1996. http://hdl.handle.net/10023/15271.
Testo completoAbstract (sommario):
A multi-disciplinary, high resolution, geophysical investigation of a Scottish Sea loch has facilitated both the reconstruction of a detailed late Quaternary para-stratigraphic model and the critical assessment of the acquisition and analytical methodologies most appropriate for the study of submerged palaeo-glaciomarine environments. Loch Ainort, situated on the eastern coast of the Isle of Skye, has been surveyed using a 192 kHz echosounder, a 400 kHz side scan sonar and a 3.5 kHz sub-bottom profiler. Lithological calibration was provided by the analysis of both in situ core data and extant terrestrial data sets. It is proposed that for the effective reconstruction of these and any other nearshore palaeo-environments a multi-disciplinary geophysical approach is essential. The critical control on success is the adherence, during interpretation, to a single unifying seismo-analytical framework. The seismo-stratigraphical analysis technique has been adapted for high- resolution work in order to provide this rigid framework. Objective descriptive analysis of the seismic traces provides a "seismic para-stratigraphy" which when combined with lithological data is used to construct a "composite para-stratigraphy". This is a process based, litho-stratigraphic interpretation that, by virtue of the detailed spatial extent afforded it by geophysical data, can be placed in a wider environmental context. The composite para-stratigraphy for the Loch Ainort basin is dominated by Loch Lomond Stadial glacial activity. Terminal and readvance limits are identified at several localities within the basin. Variable morphological styles of the glacial sequences show that deglaciation occurred in two distinct, climatically controlled, phases. The first marked by a fluctuating ice margin and the second by uninterrupted retreat and in situ ice stagnation. Sub-aerially induced debris flows occur during the initial paraglacial phase but stabilisation of exposed slopes restricts this input and rapid sedimentation of fines from sediment-rich meltwaters becomes dominant. Modern fjordic sedimentation develops after the disappearance of glacier ice.
45
Roesch, Mike J. "IDENTIFYING WILDLIFE CROSSING ZONES FOR THE PRIORITIZATION OF HIGHWAY MITIGATION MEASURES ALONG U.S. HIGHWAY 2: WEST GLACIER, MT TO MILEPOST 193". The University of Montana, 2010. http://etd.lib.umt.edu/theses/available/etd-06092010-100319/.
Testo completoAbstract (sommario):
Highways have been shown to fragment wildlife habitats and populations. In order to mitigate the effects that highways have on wildlife, it is important to assess where wildlife appear to be moving in close proximity to the highway. I surveyed for wildlife trails that approached either side of a ~64 km stretch U.S. Highway 2 (US-2) and monitored these trails with remote cameras. Ungulates, especially deer, were the most commonly photographed animals on trails. A limited number of photographs were also taken of coyote, black bear, snowshoe hare, wolf, and cougar. Camera images showed that wildlife tended to use roadside trails during hours of lower traffic volumes. I used multiple logistic regression at three scales (50 m, 250 m, and 500 m) followed by model selection with Akaikes Information Criterion to assess the impacts of certain landscape features on the location of wildlife trails (used) versus randomly generated points (unused). I examined the clustering of wildlife trails and found them to be clustered at all distance scales less than 39 kmwith the strongest clustering occurring at the 5-8 km scales. The 5 km segment of highway with the highest density of trails was located from Milepost (MP) 181-184. Crossing zones were delineated based on a combination of the number of trails, previously identified wildlife crossings, camera incidents-per-day, potential parcels of land for conservation, and highway and railroad structures in a given area (usually a 5 km segment). The results of this study may serve as useful baseline information to the Great Northern Environmental Stewardship Area working group (GNESA) and its partners to help guide future research and mitigation projects in the US-2 corridor.
46
Guarino, Thomas. "Symphonic Poem (for Orchestra)". University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1429641512.
Testo completo
47
Gessese, Alelign Fekade. "Algorithms for Bed Topography Reconstruction in Geophysical Flows". Thesis, University of Canterbury. Mechanical Engineering, 2013. http://hdl.handle.net/10092/8673.
Testo completoAbstract (sommario):
Bed topography identification in open channel and glacier flows is of paramount importance for the study of the respective flows. In the former, the knowledge of the channel bed topography is required for modelling the hydrodynamics of open channel flows, fluvial hydraulics, flood propagation, and river flow monitoring. Indeed, flow models based on the Shallow Water Approximation require prior information on the channel bed topography to accurately capture the flow features. While in the latter, usable bedrock topographic information is very important for glacier flow modellers to accurately predict the flow characteristics. Experimental techniques to infer the bed topography are usually used but are mostly time consuming, costly, and sometimes not possible due to geographical restrictions. However, the measurement of free surface elevation is relatively easy. Alternative to experimental techniques, it is therefore important to develop fast, easy-to-implement, and cost-effective numerical methods.
The inverse of the classical hydrodynamic problem corresponds to the determination of hydraulic parameters from measurable quantities. The forward problem uses model parameters to determine measurable quantities. New one-shot and direct pseudo-analytical and numerical approaches for reconstructing the channel bed topography from known free surface elevation data is developed for one-dimensional shallow water flows. It is shown in this work that instead of treating this inverse problem in the traditional partial differential equation (PDE)-constrained optimization framework, the governing equations of the direct problem can be conveniently rearranged to obtain an explicit PDE for the inverse problem. This leads to a direct solution of the inverse problem which is successfully tested on a range of benchmark problems and experimental data for noisy and noiseless free surface data. It was found that this solution approach creates very little amplification of noise.
A numerical technique which uses the measured free surface velocity to infer the channel bed topography is also developed. The one-dimensional shallow water equations along with an empirical relationship between the free surface and the depth averaged velocities are used for the inverse problem analysis. It is shown that after a series of algebraic manipulation and integration, the equation governing the inverse problem simplifies to a simple integral equation. The proposed method is tested on a range of analytical and experimental benchmark test cases and the results confirm that, it is possible to reconstruct the channel bed topography from a known free surface velocity distribution of one-dimensional open channel flows.
Following the analysis of the case of one-dimensional shallow water flows, a numerical technique for reconstructing the channel bed topography from known free surface elevation data for steep open channel flows is developed using a modified set of equations for which the zero-inertia shallow water approximation holds. In this context, the shallow water equations are modified by neglecting inertia terms while retaining the effects of the bed slope and friction terms. The governing equations are recast into a single first-order partial differential equation which describes the inverse problem. Interestingly, the analysis shows that the inverse problem does not require the knowledge of the bed roughness. The forward problem is solved using MacCormack’s explicit numerical scheme by considering unsteady modified shallow water equations. However, the inverse problem is solved using the method of characteristics. The results of the inverse and the forward problem are successfully tested against each other.
In the framework of full two-dimensional shallow water equations, an easy-to-implement and fast to solve direct numerical technique is developed to solve the inverse problem of shallow open channel flows. The main underlying idea is analogous to the idea implemented for the case of one-dimensional reconstruction. The technique described is a “one-shot technique” in the sense that the solution of the partial differential equation provides the solution to the inverse problem directly. The idea is tested on a set of artificial data obtained by first solving the forward problem.
Glaciers are very important as an indicator of future climate change or to trace past climate. They respond quickly compared to the Antarctica and Greenland ice sheets which make them ideal to predict climate changes. Glacier bedrock topography is an important parameter in glacier flow modelling to accurately capture its flow dynamics. Thus, a mathematical technique to infer this parameter from measured free surface data is invaluable. Analogous to the approaches implemented for open channel flows, easy-to-implement direct numerical and analytical algorithms are developed to infer the bedrock topography from the knowledge of the free surface elevation in one space dimension. The numerical and analytical methods are both based on the Shallow Ice Approximation and require the time series of the ablation/accumulation rate distribution. Moreover, the analytical method requires the knowledge of a non-zero glacier thickness at an arbitrary location. Numerical benchmark test cases are used to verify the suitability and applicability of the algorithms.
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Wallin, Åsa. "Investigating methods for identifying paleo surge-type glaciers or highly dynamical ice flows in Trygghamn, west Spitsbergen". Thesis, Stockholms universitet, Institutionen för naturgeografi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-131801.
Testo completoAbstract (sommario):
Surge-type glaciers exhibit a cyclic behaviour with an ice mass increase in the reservoir area during the inactive, quiescent phase and a rapid transportation of ice during the active, surge phase. In order to interpret the effects of climate change correctly it is important to distinguish between advances of surge-type glaciers and those of ‘normal’ glaciers, caused by climatic fluctuations. This is particularly important for the Arctic, which is predicted to experience the highest increase in temperature on the planet. The dynamic and mechanism of surge-type glaciers can be used for understanding both modern and past ice sheet dynamic instabilities, threshold behavior and contribution to sea level rise. They are also suggested to be analogues for land-terminating paleo ice streams and surging ice sheet lobes, which makes them highly valuable as research objects. Though in order to understand their behavior, it is important to be able to identify them. In literature the number for surge-type glaciers on Svalbard varies between 13 and 90 %, thus it is important to work out methods, other than physical observations, for identification. Aerial photographs are a powerful tool for the identification and mapping of landforms and ice structures and for reconstructing glacier distribution. Though for mapping of ice facies and structures within the glaciers, which provide important information regarding the glaciers past dynamics, and is an important part of the identification, fieldwork is essential. Fieldwork is also much needed in order to interpret the landforms and their genesis correctly. It is suggested that the use of multiple methods for identifying surges, or highly dynamical ice flows, will improve the result and the reliability will increase. In this thesis two different methods, structural glaciology and glacial geomorphology, have been used for interpreting the past behaviour of the four glaciers in Trygghamna, west Spitsbergen. Structural glaciology provides a way to determine the dynamic of surge-type glaciers for both the quiescent- and surge phase. By using glacial geomorphology it is possible to reconstruct former extent and thickness of small valley glaciers. The glaciers of Trygghamna exhibit evidence of a dynamic past, of which Harrietbreen and Kjerulfbreen bear enough evidence to be considered as surge-type glaciers. The lack of landforms on the forelands of Kiærbreen and Protektorbreen makes the interpretation difficult, though the ice facies and structures within the ice cave on Protektor-breen provide additional information and thus this glacier should at least be classified as a highly dynamical ice flow. Thus it is considered to not be suitable to only use one data type to determine whether a glacier is of surge-type or not. By use multiple methods the result will improve and the reliability will increase. The two methods used for this thesis are considered to be the least amount of methods needed in order to establish whether a glacier is of surge-type or not.
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Mountain, Keith Richard. "A clear sky net radiation model for the high elevation glacial environment /". The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487681148542966.
Testo completo
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Stokes, Christopher Richard. "The geomorphology of palaeo-ice streams : identification, characterisation and implications for ice stream functioning". Thesis, University of Sheffield, 2001. http://etheses.whiterose.ac.uk/14815/.
Testo completoAbstract (sommario):
Ice streams are the dominant drainage pathways of contemporary ice sheets and their location and behaviour are viewed as key controls on ice sheet stability. Identifying palaeo-ice streams is of paramount importance if we are to produce accurate reconstructions of former ice sheets and examine their critical role in the oceanclimate system. Many workers have invoked palaeo-ice streams from a variety of former ice sheets, despite a limited understanding of their glacial geomorphology. This thesis addresses the problem by predicting several diagnostic geomorphological criteria indicative of ice stream activity. These are developed objectively from the known characteristics of contemporary ice streams and can be summarised as: large flow-set dimensions (>20 km wide and >150 km long), highly convergent flow patterns, highly attenuated subglacial bedforms (length:width >10: 1), Boothia-type dispersal plumes, abrupt lateral margins «2 km), ice stream marginal moraines, evidence of pervasively deformed till, and submarine sediment accumulations (marine-terminating ice streams only). Collectively, the criteria are used to construct conceptual landsystems of palaeo-ice stream tracks. Using satellite imagery and aerial photography to map glacial geomorphology, identification of the criteria is used to validate the location of a previously hypothesised ice stream and identify a hitherto undetected palaeo-ice stream from the former Laurentide Ice Sheet. Implications for ice stream basal processes are explored and their ice sheet-wide significance is assessed. On Victoria Island (Arctic Canada) five of the geomorphological criteria are identified and the extent of the marine-based M'Clintock Channel Ice Stream is reconstructed at 720 km in length and 140 km in width. The ice stream (operating between 10,400 and 10,000 yr BP) was located within a broad topographic trough, but internal glaciological processes, rather than properties of the bed controlled the margin locations. It eroded into pre-existing unconsolidated sediments and left a spectacular pattern of subglacially-produced landforms, recording a snapshot view of the bed prior to ice stream shut-down. Sediment availability appears critical to its functioning (deformable bed?) and the debris flux of the ice stream is inferred to have been high. Frictional shut-down occurred once down-cutting through sediments reached hard bedrock close to the terminus. The presence of four of the geomorphological criteria are used to identify a terrestrial ice stream which drained the Keewatin Sector of the Laurentide Ice Sheet between ca. 10,000 and 8,500 yr BP. Its size is reconstructed at over 450 km in length and 140 km in width, and it left behind a subglacial bedform pattern consisting of highly attenuated drumlins (length:width ratios up to 48: 1) displaying exceptional parallel conformity. This represents an isochronous bedform pattern and variations in lineament elongation ratio are thought to be a useful proxy for ice velocity. Highest elongation ratios occur immediately downstream of a topographic step where the ice stream entered a sedimentary basin. It is inferred that the ice stream was triggered by climatic warming which altered the ice sheet configuration and the thermal state of the bed. A switch from cold to warm-based conditions probably triggered rapid basal sliding. The ice stream (and a tributary) shut down when it ran out of ice, causing widespread thinning of the ice sheet and subsequent deglaciation. These ice streams denote considerable ice sheet instability over both hard and soft (deformable) beds and emphasise the enormous effects that ice streams had in controlling the deglaciation of the Laurentide Ice Sheet.