Дисертації з теми "Glacier mass balance estimation"
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Podsiadło, Iwona Katarzyna. "Methods for the analysis of time series of multispectral remote sensing images and application to climate change variable estimations." Doctoral thesis, Università degli studi di Trento, 2021. http://hdl.handle.net/11572/322351.
Повний текст джерелаHuss, Matthias. "Past and future changes in glacier mass balance /." Zürich : ETH, 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000256345.
Повний текст джерелаWiklund, Sara. "Long-term glacier mass balance of Nordenskiöldbreen, Svalbard." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-295789.
Повний текст джерелаDen globala uppvärmningen som sker just nu har en påverkan över hela jorden och glaciärer på Svalbard genomgår snabba förändringar som följd. På Svalbard har den årliga medeltemperaturen stigit sedan början av 1900-talet och i en klimatprojicering förväntas temperaturen att fortsätta stiga. Den glaciala massbalansen är viktig för att övervaka glaciärers respons till klimatförändringar. I detta arbete modelleras Nordenskiöldbreens massbalans från 1957 till 2016 med hjälp av en temperaturindex modell. Den meteorologiska data som används i modellen, nederbörd och temperatur, har mätts vid en väderstation i Longyearbyen sedan 1957. Med den långa tidsperioden i modellen blir långsiktiga trender i massbalans, nederbörd och temperatur tydliga. Massbalansen kan även korreleras mot temperatur och nederbörd, vilket ger viktig information om hur dessa påverkar glaciärers beteenden. De resultat som framkommer kan användas för att förutspå hur glaciärer förändras i framtiden med en klimatändring. I simuleringen har Nordenskiöldbreens massbalans en negativ trend, nederbörd har ingen trend och temperatur har en positiv trend. Det är temperatur som styr den långsiktiga massbalansen och den kortsiktiga mellanårs-massbalansen styrs av nederbörds fluktuationer.
Huss, Matthias Boes Robert. "Past and future changes in glacier mass balance /." Zürich : Versuchsanstalt für Wasserbau, Hydrologie und Glaziologie, ETH Zürich, 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000263371.
Повний текст джерелаFujita, Koji, and 耕史 藤田. "Effect of precipitation seasonality on climatic sensitivity of glacier mass balance." Elsevier, 2008. http://hdl.handle.net/2237/11360.
Повний текст джерелаRye, Cameron James. "Spatially distributed modelling of regional glacier mass balance : a Svalbard case study." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609569.
Повний текст джерелаHerdes, Emilie. "Evolution of Seasonal Variations in Motion of the Kaskawulsh Glacier, Yukon Territory." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31835.
Повний текст джерелаKilic, Lise. "Estimation des paramètres de surface des océans et de la banquise à partir d’observations micro-ondes basses fréquences." Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS167.
Повний текст джерелаThe oceans and sea ice play an important role in the climate and weather system. A future low-frequency passive microwave satellite mission designed to observe the polar regions is currently under study at the European Space Agency for the expansion of the Copernicus programme. Passive microwave satellite observations provide all-weather observation of the Earth surface, both day and night. In this thesis, we are interested in estimating ocean and ice surface parameters from low-frequency passive microwave satellite observations. The objective is to develop new methods for estimating these parameters that are more efficient and adapted to the future passive microwave satellite mission CIMR (Copernicus Imaging Microwave Radiometer). The first part of the thesis deals with the estimation of ocean parameters such as sea surface temperature, salinity and ocean wind speed. The second part deals with the estimation of sea ice parameters such as sea ice concentration, snow depth and snow-ice interface temperature. Finally, with the methods developed in this thesis, the performances of the CIMR mission are evaluated and compared with the current missions
Bergman, Ottar. "A Regional Analysis of Changing Climate Conditions and Glacier Mass Balance in Svalbard." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-383930.
Повний текст джерелаGustavsson, Maja. "Mass Balance of the High-Arctic Glacier Nordenskiöldbreen, Svalbard, in a Changing Climate." Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-388495.
Повний текст джерелаGlaciärer som smälter är en av de största bidragen till den förhöjda havsnivån. Det är därför viktigt att studera Svalbards glaciärer för att kunna svara på hur den arktiska uppvärmningen påverkar issystemen. En tidsserie över massbalansen för glaciären Nordenskiöldbreen skapades genom höjdobservationer från stavmätningar befintliga på glaciären. I nästa steg analyserades kopplingen mellan glaciärmassbalansen och väderparametrarna som observerats vid närliggande meteorologiska stationer. Den totala netbalansen på glaciären Nordenskiöldbreen visade sig vara negativ (-0.09 m w.e. per år) mellan år 2005 och 2017. Massbalansen under sommarsäsongen korrelerade starkast med maximal lufttemperatur medan vinterbalansen var mest påverkad av molntäcke och temperatur, snarare än nederbörd. Resultaten visar att nederbörd observerad vid närliggande väderstationer inte är representativ för nederbördsmängder observerade på glaciären.
Tinder, Phaedra C. "Ocean-Ice Interactions at Breiðamerkurjökull Glacier, Southeast Iceland." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1339663923.
Повний текст джерелаWright, Andrew Philip. "The impact of meltwater refreezing on the mass balance of a high Arctic glacier." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435704.
Повний текст джерелаDavid, Höglin. "Regional and Local Factors Influencing the Mass Balance of the Scandinavian Glaciers." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-311152.
Повний текст джерелаEnligt klimatmodeller kommer en ökning av växthusgaser i atmosfären leda till en ökning av temperaturen på jorden, den ökningen kommer främst att ske på höga latituder. Glaciärer är bra indikation på förändrat klimat på grund av deras korta responstid när klimatet ändrar sig. För tillfället finns det ca 1900 glaciärer utspridda i de Skandinaviska bergen. Eftersom Skandinavien är så avlångt är det en skillnad i meterologiska och klimatiska förhållanden, både i en nord-syd riktning men även i en öst-väst riktning med kontinentala glaciärer i öst och mer marina i väst. Klimat och glaciärdata för 13 olika glaciärer i Skandinavien, 5 från Sverige och 8 ifrån Norge har samlats in och en statistisk analys, principle component analysis (PCA) har gjorts för att se vad som påverkar massbalansen för glaciärerna. De klimat parametrar som har undersökts är Nordatlantsika oscillationen (NAO), Arktiska oscillationen (AO) och solfläckar tillsammans med massbalans, equilibrium line altitude (ELA) och area för glaciärerna. Tre grupperingar har hittats som kan kopplas till olika klimatvariabler och PCA visar extremår för NAO och AO samt en glaciär som har den största arean. PCA analysen visade att alla variabler korrelerade till NAO och AO med omkring 40 % och vi kan dra slutsatsen att det finns en drivande regional och lokal kraft inom vårat dataset där NAO och AO är viktigast för massbalansen.
Thomson, Laura Irene. "Connections Between the Mass Balance, Ice Dynamics, and Hypsometry of White Glacier, Axel Heiberg Island, Nunavut." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35106.
Повний текст джерелаPalmgren, Rikard. "Reconstructing the Long-Term Mass Balance of Brewster Glacier, New Zealand, Using a Degree-Day Approach." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-324325.
Повний текст джерелаWarmer climate is something that is continuously affecting glaciers across the planet and has during the last century gained a global increase in negative mass balances. This trend has contributed to sea-level rise and had other impacts on water resources. Monitoring and observing the worlds glaciers is therefore very important and by creating models that allows insight in the glacier response to atmospheric fluctuation, it is possible to obtain deeper knowledge on how the global warming will develop. In this project, the mass balance of Brewster Glacier, New Zealand, is reconstructed for the period 2005 – 2015 using a degree-day approach. The input for the model has been obtained from a recent downscaling project that has produced atmospheric data over the period 1979 – 2015 that allows the model to run at a daily temporal resolution. The results presented are going to contribute to a greater insight in the degree-day model as to whether the approach of using simple air temperature and precipitation data are reliable to portray the mass balance of glaciers.
McLay, Nicholas Ross. "Ice Velocity and Mass Balance Study of the Skelton Glacier, Antarctica, Using Remote Sensing and GIS Techniques." Thesis, University of Canterbury. Gateway Antarctica, 2013. http://hdl.handle.net/10092/7883.
Повний текст джерелаEriksson, Rehn Ida. "Mass balance and local characteristics of three glaciers in southern Norway, between 1980 and 2018 : An analysis of the mass balance and the local characteristics of Ålfotbreen, Storbreen and Gråsubreen." Thesis, Stockholms universitet, Institutionen för naturgeografi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-184671.
Повний текст джерелаMOSCONI, BORIS. "SOME EXAMPLES OF MODELLING GLACIER MASS BALANCE AND RESULTS FROM SNOW MELT MITIGATION STRATEGIES IN THE ITALIAN ALPS." Doctoral thesis, Università degli Studi di Milano, 2013. http://hdl.handle.net/2434/216123.
Повний текст джерелаSpiess, Marinka [Verfasser], Frank [Akademischer Betreuer] Lehmkuhl, Christoph [Akademischer Betreuer] Schneider, and Dieter [Akademischer Betreuer] Scherer. "Remote sensing derived spatial patterns of glacier mass balance in Tibet / Marinka Spiess ; Frank Lehmkuhl, Christoph Schneider, Dieter Scherer." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1130402800/34.
Повний текст джерелаYoung, Emma Victoria. "Determining the ability of terrestrial time-lapse microgravity surveying on a glacier to find summer mass balance using gravitational modeling." Master's thesis, Temple University Libraries, 2017. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/473458.
Повний текст джерелаM.S.
Mass loss of alpine glaciers presently account for about half of the cryospheric contribution to the global sea-level rise. Mass balance of alpine glaciers has predominantly been monitored by; (1) glaciological and hydrological methods, and (2) satellite gravimetric methods using data from NASA’s Gravity Recovery and Climate Experiment (GRACE) satellite mission. However, the former can be logistically costly and have large extrapolation errors: measurements taken at monthly temporal scales are expensive and have a spatial resolution of roughly one kilometer. The latter provides monthly mass-balance estimates of aggregates of alpine glaciers, although the spatial resolution (~300 km) is far too coarse for assessing individual glaciers’ mass balance. Ground-based, time-lapse microgravity measurements can potentially overcome some of the disadvantages of the glaciological, hydrological, and satellite gravitational methods for assessing mass changes and their spatial distribution on a single glacier. Gravity models were utilized to predict the gravity signals of the summer-time mass balance, changes in the seasonal snow cover outside of the glacier, and the vertical gravity gradient (VGG) needed for the free-air correction on Wolverine Glacier, AK. The modeled gravity signal of the summer-time mass balance (average of -0.237 mGal) is more than an order of magnitude larger than the uncertainty of conventional relative gravimeters (±0.007 mGal). Therefore, modeling predict that the time-lapse gravitational method could detect the summer-time mass balance on Wolverine Glacier. The seasonal snow effect was shown to have the greatest influence (~ -0.15 mGal) on the outer 100 m boundary of the glacier and minimal effect (~ -0.02 mGal) towards the center, both larger than the uncertainty of relative gravimeters. The VGG has a positive deviation, about -0.1 to -0.2 mGal/m, from the normal VGG (-0.309 mGal/m). Thus, seasonal snow effect and VGG need to be correctly accounted for when processing gravity measurements to derive the residual gravity signal of the glacier mass balance. Accurate measurements of elevation changes, seasonal snow depth, and the VGG should be performed in future gravity surveys of glaciers.
Temple University--Theses
Honsaker, William M. "Late-Holocene Chronology of the Istorvet Ice Cap, Liverpool Land, East Greenland." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1307320783.
Повний текст джерелаMORETTI, MASSIMILIANO. "Development and climate interpretation of mass balance and future assessment about Alpine glaciers, through theoretical models, included in Project of Interest NextData." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2016. http://hdl.handle.net/10281/104534.
Повний текст джерелаWagnon, Patrick. "Analyse du bilan d'énergie d'un glacier tropical : application à la relation glacier-climat." Phd thesis, Université Joseph Fourier (Grenoble ; 1971-2015), 1999. http://www.theses.fr/1999GRE10067.
Повний текст джерелаWagnon, Patrick. "Analyse du bilan d'énergie d'un glacier tropical : application à la relation glacier-climat." Phd thesis, Grenoble 1, 1999. http://tel.archives-ouvertes.fr/tel-00693949.
Повний текст джерелаMacdonald, Oliver George. "Coupling glacier mass balance and meltwater yield in the European Alps with future climate change : downscaling from integrations of the HADCM model." Thesis, University of Salford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402055.
Повний текст джерелаWeidemann, Stephanie Suzanne. "Glacier response to climate variability and climate change across the Southern Andes." Doctoral thesis, Humboldt-Universität zu Berlin, 2021. http://dx.doi.org/10.18452/22954.
Повний текст джерелаGlacier mass loss of the Southern Andes contributes largely to sea-level rise during recent decades and also affects the regional water availability. Despite the overall glacier retreat of most glaciers in Patagonia and Tierra del Fuego, a recent increase in mass loss of individual glaciers has been observed. The recent variability of climate and climatic mass balance for selected glaciated study sites in Patagonia and Tierra del Fuego are investigated in this thesis. Improving our understanding on the spatial and temporal variations of climatic mass balance processes, its atmospheric drivers, and their impact on the recently observed individual glacier behavior are further important aims. Since climate variability is the key driver of local changes in the cryosphere in the Southern Andes, a unique record of meteorological observations across the Gran Campo Nevado Ice Cap in Southernmost Patagonia was analyzed with regard to main climate features and the relationship between the in-situ observations, large-scale climate modes and mesoscale weather patterns. Furthermore, recent climatic mass balance variability was simulated for selected glaciers in Southern Patagonia and Tierra del Fuego by implementing the ’COupled Snow and Ice energy and MAss balance model’ COSIMA. Contrasting patterns of positive simulated annual climatic mass balance and clearly negative geodetic mass balance were found for two neighboring glaciers of the Southern Patagonia Icefield between 2000 and 2014. This highlights the importance of understanding of both, the climatic mass balance, and the ice-dynamical processes. Climatic mass balance simulations were further used to derive glacier steady-state conditions for recent and past glacier extents of Schiaparelli Glacier, aiming for a model-based approximation of climate conditions during the Little Ice Age.
Klingbjer, Per. "Glaciers and climate in northern Sweden during the 19th and 20th century." Doctoral thesis, Stockholm : Institutionen för naturgeografi och kvartärgeologi, Stockholms universitet, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-92.
Повний текст джерелаMohd, Farooq Azam. "Relation climat-glacier dans la zone de transition entre climat aride et mousson indienne : un cas d'étude dans l'Himachal Pradesh Inde." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENU032/document.
Повний текст джерелаThe Hindu-Kush Karakoram Himalayan (HKH) region is the largest snow and ice reservoir on the planet outside the Polar Regions. In the HKH region the mass balance and meteorological observations are sparse and the historical knowledge is mainly concentrated on snout fluctuation records. Hitherto, the understanding of glacier-climate relationship is poor in the HKH region. Therefore, the goal of the present work is to improve the understanding of glacier-climate relationship on a representative glacier ‘Chhota Shigri' in the western Himalaya. A number of in-situ measurements concerning mass balances, surface velocity, ice thickness and meteorology have been collected during and before the present PhD work since 2002. These data sets were first analyzed to understand the glacier behaviour and then used in the models to understand the glacier relationship with climatic variables. Between 2002 and 2013, glacier showed a mass wastage/unsteady-state conditions with a cumulative mass loss of –6.45 m w.e. Further, the ice flux analysis over 2002-2010 suggested that the glacier has experienced a period of steady-state or slightly positive mass balance during the 1990s. We first reconstructed the annual and seasonal mass balances using a degree day model from simple meteorological variables, precipitation and temperature. This reconstruction allowed us to examine the mass balances between 1969 and 2012. Since 1969, Chhota Shigri showed a moderate mean mass wastage at a rate of −0.30 m w.e. a-1. A period of steady-state between 1986 and 2000, already suggested by ice flux analysis and geodetic measurements, was confirmed. The mass balance evolution of this glacier revealed that the mass wastage is recent and provide a very different pattern than that of usually found in the literature on western Himalayan glaciers. The analysis of decadal time scale mass balances with meteorological variables suggested that winter precipitation and summer temperature are almost equally important drivers controlling the mass balance pattern of this glacier. Second, in order to understand the detailed physical basis of climatic drivers, a surface energy balance study was also performed using the in-situ meteorological data from the ablation area of Chhota Shigri Glacier. Net all-wave radiation was the main heat flux towards surface with 80% contribution while sensible, latent heat and conductive heat fluxes shared 13%, 5% and 2% of total heat flux, respectively. Our study showed that the intensity of snowfall events during the summer-monsoon is among the most important drivers responsible for glacier-wide mass balance evolution of Chhota Shigri Glacier. However, due to the lack of precipitation measurements and the strong precipitation gradient in this region, the distribution of precipitation on the glacier remains unknown and needs further detailed investigations
McCoy, Kurt J. "Estimation of vertical infiltration into deep Pittsburgh coal mines of WV-PA a fluid mass balance approach /." Morgantown, W. Va. : [West Virginia University Libraries], 2002. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=2745.
Повний текст джерелаTitle from document title page. Document formatted into pages; contains x, 150 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 87-90).
Runeskog, Henrik. "Continuous Balance Evaluation by Image Analysis of Live Video : Fall Prevention Through Pose Estimation." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-297541.
Повний текст джерелаDjupinlärningstekniken Kroppshållningsestimation är ett lovande medel gällande att följa en person och identifiera dess kroppshållning. Eftersom kroppshållning och balans är två närliggande koncept, kan användning av kroppshållningsestimation appliceras till fallprevention. Genom att härleda läget för en persons tyngdpunkt och därefter läget för dess tryckcentrum, kan utvärdering en persons balans genomföras utan att använda kraftplattor eller sensorer och att enbart använda kameror. I denna studie har en kroppshållningsestimationmodell tillsammans med en fördefinierad kroppsviktfördelning använts för att extrahera läget för en persons tryckcentrum i realtid. Den föreslagna metoden använder två olika metoder för att utvinna djupseende av bilderna från kameror - stereoskopi genom användning av två RGB-kameror eller genom användning av en RGB-djupseende kamera. Det estimerade läget av tryckcentrat jämfördes med läget av samma parameter utvunnet genom användning av tryckplattan Wii Balance Board. Eftersom den föreslagna metoden var ämnad att fungera i realtid och utan hjälp av en GPU, blev valet av kroppshållningsestimationsmodellen inriktat på att maximera mjukvaruhastighet. Därför användes tre olika modeller - en mindre och snabbare modell vid namn Lightweight Pose Network, en större och mer träffsäker modell vid namn High-Resolution Network och en model som placerar sig någonstans mitt emellan de två andra modellerna gällande snabbhet och träffsäkerhet vid namn Pose Resolution Network. Den föreslagna metoden visade lovande resultat för utvinning av balansparametrar i realtid, fastän den största felfaktorn visade sig vara djupseendetekniken. Resultaten visade att användning av en mindre och snabbare kroppshållningsestimationsmodellen påvisar att hålla måttet i jämförelse med större och mer träffsäkra modeller vid användning i realtid och utan användning av externa dataprocessorer.
FUGAZZA, DAVIDE. "ALL EYES ON GLACIERS: REMOTE SENSING OF THE CRYOSPHERE." Doctoral thesis, Università degli Studi di Milano, 2019. http://hdl.handle.net/2434/623598.
Повний текст джерелаDumont, Marie. "Détermination de l'albédo des surfaces enneigées par télédétection : application à la reconstruction du bilan de masse du glacier de Saint Sorlin." Phd thesis, Université Paris-Est, 2010. http://tel.archives-ouvertes.fr/tel-00582925.
Повний текст джерелаRiger-Kusk, Mette. "Ice dynamics of the Darwin-Hatherton glacial system, Transantarctic Mountains, Antarctica." Thesis, University of Canterbury. Geography, 2011. http://hdl.handle.net/10092/6602.
Повний текст джерелаHedfors, Jim. "Force Budget Analysis of Glacier Flow : Ice Dynamical Studies on Storglaciären, Sweden, and Ice Flow Investigations of Outlet Glaciers in Dronning Maud Land, Antarctica." Doctoral thesis, Uppsala University, Department of Earth Sciences, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4219.
Повний текст джерелаThis thesis contributes to the understanding of glacier response to climate change by ice dynamical studies on Storglaciären, Sweden, and Bonnevie-Svendsenbreen, Kibergbreen and Plogbreen in Dronning Maud Land, Antarctica. Ice surface velocities, ice geometry and temperature information is fed through a force budget model to calculate ice mass outflux of these glacial systems via three-dimensional stress distributions for a flux-gate.
Field data were collected through repeated DGPS and GPR observations on Storglaciären between July 2000 to September 2001 and on Kibergbreen and Plobreen during the SWEDARP 2002/03 expedition to Antarctica. The work was strongly supported by remotely-sensed information.
The results from Storglaciären show a strength in the force budget model to discern both spatial and temporal variability in ice dynamical patterns. It highlights the influence of seasonality and bedrock topography upon glacier flow. A modeling experiment on Bonnevie-Svendsenbreen suggested that ice temperature increases substantially under conditions of high stress (≥0.4 MPa) due to strain-heating. This provides a positive feedback loop, increasing ice deformation, as long as it overcomes the advection of cool ice from the surface. These results explain, to some extent, the mechanism behind fast flowing ice streams. Mass flux caclulations from Bonnevie-Svendsenbreen suggest that the outflux given from force budget calculations can be used as a gauge for influx assuming steady state conditions. Plogbreen receives an influx of 0.48±0.1 km3 a-1 and expedites a discharge volume of 0.55±0.05 km3 a-1. This indicative negative mass balance is explained by a falling trend in upstream accumulation and the recent rise in global sea level, as it is likely to induce glacier acceleration due to a reduction in resistive forces at the site of the gate. This result is comparable with other Antarctic studies reporting negative mass balances, e.g. from WAIS, as caused by changes in the global atmospheric circulation pattern.
Muñoz-Cobo, Belart Joaquín. "Bilan de masse des glaciers islandais depuis 1945 : reconstruction et relation avec la variabilité climatique." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30236.
Повний текст джерелаThe mass balance of a glacier is strongly connected to climate. At high latitudes, mass balance is typically controlled by snow accumulation during the winter and the glacier ablation during the summer. In Iceland, direct mass balance observations have been mostly focused on the three largest ice caps (~600 to ~8000 km2), measured in situ for the last 25 years. There are, however, glaciers and ice caps distributed over all quarters of the country that lack mass balance observations. Remote sensing data with the capability to retrieve the glacier surface geometry through Digital Elevation Models (DEMs) are valuable tools to measure mass balance using the geodetic method. For a typical Icelandic glacier (with an area between 1 km2 and hundreds of km2), this can be optimally achieved from optical stereoscopic imagery, emplaced in airborne or spaceborne sensors, and from airborne lidar. This thesis focuses on remote sensing techniques to accurately measure geodetic mass balance from seasonal to decadal time spans and the relationship of mass balance to climate. As an example of seasonal mass balance, the winter mass balance of Drangajökull was measured from satellite sub-meter stereo images at the beginning, middle and end of the 2014-2015 winter using data from the Pléiades and WorldView-2 satellites. The results were complemented with in situ snow density measurements and validated with snow thickness measurements. The study concludes that images from the sensors mentioned above may often be used to monitor seasonal mass balance without tedious field logistics. A vast archive of aerial photographs exists for Iceland extending back to 1945. Since then, most glaciers were surveyed every 5 to 20 years. In addition, a wealth of modern satellite stereo images is available since the early 2000s as well as airborne lidar data in 2008-2013. This creates a unique dataset to construct a 70-year time series of geodetic mass balances.[...]
Davaze, Lucas. "Quantification du bilan de masse des glaciers de montagne à l'échelle régionale par télédétection spatiale optique." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAU022/document.
Повний текст джерелаBeyond their iconic role of climate change, mountain glaciers can be considered as Earth’ essential component and natural “climate-meter”. Despite their small spatial coverage (0.5% of emerged land), mountain glaciers contribute as high as 30% of the observed sea-level rise. In some regions, they are considered as essential issues because of their importance in terms of potable water, agriculture, hydroelectricity or natural hazards. A small share is however monitored in situ (<0.0025%) and their fluctuations at regional scale are poorly known.Thanks to the development of high spatial resolution satellite sensors (metric to decametric), new methods are today available to significantly increase the number of monitored glaciers. After a state of the art of the existing methods and an identification of the limitations, we focused our attention on the development of two methods.The first one is based on the automatic detection of the snow/ice interface altitude (i.e. snowline) at the glacier surface from optical satellite images. This altitude, when estimated at the end of summer, is a proxy of the annual glacier-wide mass change at the glacier surface (called surface mass balance, SMB). Using this approach, we estimated the annual SMBs of 239 glaciers in the European Alps and 82 glaciers in the tropical Andes for the period 2000-2016 and 2000-2018, respectively. The mean mass loss are -0.74 and -1.29 m water equivalent per year for the two regions, respectively. This approach allowed to derive the first dataset of annual SMBs for individual glaciers at regional scale from optical remote sensing. We found significant relationships between the computed SMBs and the glacier morpho-topographic features (e.g. slope, median altitude, …), with steeper and higher glaciers, experiencing less mass losses. Comparison with in situ monitored SMBs revealed an overestimation of mass losses from in situ estimates, due to a low representativeness of steep glaciers (>20°) in the in situ datasets. Our study also revealed heterogeneous inter-annual variability across the European Alps, partially explained by the climatic context of the studied sub-regions, thanks to the analysis of climate reanalysis data.We developed a second method to derive the annual and summer SMBs from albedo maps, computed from MODIS images. With an application on 30 glaciers in the French Alps, this work opened the way toward a regional application of this method, in order to estimate both annual and summer SMBs.By performing regional applications on different glacierized regions, we developed and validated methods capable of deriving the annual and summer SMBs of individual mountain glaciers at regional scale, from optical remote sensing data. These data could then be used to (1) assess the impact of peculiar climatic conditions onto mountain glaciers; (2) investigate possible meteorological conditions driving the documented glacier fluctuations; (3) calibrate and validate glacio-hydrological models used to estimate the current and future contributions of mountain glaciers to the hydrological functioning of mountain catchments and to sea level rise
Dussaillant, Inés. "Contribution récente des glaciers des Andes à la ressource en eau et à la hausse du niveau marin : apport des observations satellitaires." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30161.
Повний текст джерелаAndean glaciers are amongst the fastest shrinking and the largest contributors to sea level rise in the world. They also represent crucial water resources in the vast semi-arid portions of this large Andes Cordillera (10°N-56°S), sustaining river runoff during dry periods and buffering the effects of droughts. Despite the widespread shrinkage of these glaciers, direct measurement of glacier fluctuations in the Andes are sparse, short-termed and in many cases incomplete, preventing the accurate quantification of recent ice loss for the entire mountain range. Comprehensively quantifying the magnitude of this loss at different special scales is crucial to better constrain future economical, ecological and social impacts. First, we evaluated the performance of a methodology to calculate glacier mass changes on Andean glaciers using time series of digital elevation models (DEMs) derived from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) stereo images. Over our validation zone, the Northern Patagonian Icefield, we found strongly negative icefield-wide mass balance rates of -1.06 ± 0.14 m w.e. yr-1 for the period 2000-2012, in good agreement with estimates from earlier studies and with a second independent estimate (-1.02 ± 0.21 m w.e. yr-1) obtained by differencing the better resolved Shuttle Radar Topography Mission (SRTM) DEM with a Satellite pour l'Observation de la Terre 5 (SPOT5) DEM. Importantly, this work permitted us to (i) validate "ASTER monitoring Ice towards eXtinction" (ASTERIX) method over the Andes; (ii) confirm the lack of penetration of the C-band SRTM radar signal into the NPI snow and firn except for a small high altitude region (above 2900 m a.s.l.) with negligible effects on NPI-wide mass balance; and (iii) provide the basis for an analysis of NPI mass balance changes during different sub-periods between 1975 and 2016 using additional DEMs. Then, we processed more than 30000 ASTER DEMs to calculate the integrated volume of ice lost by Andean glaciers during the past two decades. Andes-wide mass loss amounts to -22.9 ± 5.9 Gt yr-1 (-0.72 ± 0.22 m w.e. yr-1) for the entire period (or -26.0 ± 6.0 Gt yr-1 including subaqueous losses). All regions show consistent glacier wastage, with the most negative mass balance rates in the Patagonian Andes (-0.78 ± 0.25 m w.e. yr-1) and Tropical Andes (-0.42 ± 0.24 m w.e. yr-1). Relatively moderate loss (-0.28 ± 0.18 m w.e. yr-1) is measured in the intermediate regions of the Dry Andes. The inter-decadal patterns of glacier mass loss is an important contribution of this work, observed for the first time at an Andes-wide scale. We observe steady thinning rates in the Tropics and south of 45°S. Conversely, glaciers from the Dry Andes were stable during the 2000s, shifting to drastic thinning rates during the 2010s, coinciding with conditions of sustained drought since 2010. The evaluation of the imbalanced glacier contribution to river discharge during these two decades revealed that glaciers partially helped to mitigate the negative impacts of this sustained drought in the Dry Andes. The results obtained in this thesis contribute to the understanding of recent Andean glacier evolution at a local, regional and Andes-wide scale. We provide a high-quality, multi-decadal dataset that will be useful to constrain the diversity of present 21st century Andes-wide mass loss estimates, in the pursuit of the good calibration of glaciological and hydrological models intended to project future glacier changes and to improve water resource management in the Andes
Khedekar, Mayur. "Temperature Based Estimation of the Time-Resolved Massflux of ICE Exhaust Gas Flow." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-300050.
Повний текст джерелаSyftet med studien var att tillhandahålla information och erfarenhet från fina trådtermoelement (TC) eller motståndstrådstermometrar (RWT) temperatursignaler för att uppskatta den tidsupplösta värmeöverföringskoefficienten. Metoden med konstant flöde antogs i studien och mediet som användes i denna studie var luft. Här har värmebalansekvationen beskrivits, olika Nu-korrelationer och diskuterat ytterligare potentiella hinder och svårigheter man kan stöta på vid beräkning av värmeöverföringskoefficienten. Som en lösning föreslogs användning av en lämplig värmebalansekvation och lågpassfilter eftersom detta ger en mer exaktpassform. Undersökningen genomfördes för Reynoldsnummer (Re) 103 till 107 och Prandlt nummer (Pr) 0,734. Effekten av Re och Pr på Nusselts-numret (Nu) runt en cylinder representerades och alla resultat jämfördes med GT-POWER-motorns simuleringsprogram.
Viani, Alessandra. "Fonctionnement hydro-glaciologique du bassin versant de l'Arve dans les Alpes françaises : variabilité climatique et sur la disponibilité de la ressource en eau." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAU015/document.
Повний текст джерелаGlacier recession and the anticipation of spring snow melt driven by a warming climate could lead to changes in the hydrological cycle affecting not only the headwater catchments but also the areas downstream. In order to correctly predict the magnitude of future possible changes and to consider appropriate strategies of water management, a good understanding of the interaction between glaciers, climate and hydrology is needed. The aim of this study is to assess the effect of climate variability on the hydro-glaciological behaviour and its consequence on water availability in the Arve River catchment (French Alps) since 1960. It covers 1958 km2 and is composed by five nested catchments (Arveyron d’Argentière, Arveyron de la Mer de Glace, Arve at Pont des Favrands, Arve at Sallanches and Arve at Bout du Monde), all influenced by glacier and snow melt but characterized by various percentages of glacier cover ranging from 5 to 53%. This research is based on a long dataset of in situ or remote sensing glaciological, meteorological, hydrological and snow cover area data.Trend analyses are performed on the hydrological and meteorological data at all the considered sites. The seasonal cycle of each catchment is fitted using a mathematical function, namely the asymmetric peak model, and changes in the discharge are related to observed changes in the meteorological variables and the glaciers’ evolution. Results point out a contrasting behaviour among the catchments characterized by different glacier covers, showing an increasing trend on the discharge values in highly glacierized catchments (with a glacier cover >30%) and a decrease in the low glacierized ones. The sensitivity of the seasonal cycle to the future climate is evaluated. In the mid-21st century the annual runoff would be reduced by 16% for Arveyron d’Argentière and 31% for Arveyron de la Mer de Glace. Over the summer season, a detailed quantification of each term of the hydrological balance equation, as well as their uncertainties, on the Argentière and Mer de Glace-Leschaux drainage basins allows to underline the importance of considering the groundwater transfers to represent and predict the hydro-glaciological behaviour of a considered catchment. Two different distributed temperature index melt models coupled with a linear reservoir discharge model are used on the Arveron d’Argentière catchment over the 1960–2009 period. The calibration is carried out against discharge only and with a multi- criteria approach considering the discharge, the snow cover area and the glacier-wide annual mass balance values at daily time step. Results demonstrate the suitability of the use of a classical degree day model in simulating the hydro-glaciological behaviour and the subglacial water production of a highly glacierized catchment. A KGE of 0.85 is obtained between the observed and simulate discharge values over the 1960–2004 period. The use of a multi-criteria approach seems to reduce the simulation uncertainties
Reznichenko, Natalya. "Rock Avalanches on Glaciers: Processes and Implications." Thesis, University of Canterbury. Geological Sciences, 2012. http://hdl.handle.net/10092/6524.
Повний текст джерелаBalland, Laurent. "Contribution à l'estimation des paramètres cinétiques et énergétiques de systèmes chimiques en milieux homogène et hétérogène dans un réacteur calorimétrique." Rouen, 1997. http://www.theses.fr/1997ROUES054.
Повний текст джерелаGardner, Alex Sandy. "Surface mass balance of Arctic glaciers: Climate influences and modeling approaches." Phd thesis, 2010. http://hdl.handle.net/10048/1250.
Повний текст джерелаChi, Zhaohui 1982. "Investigation of Glacial Dynamics in the Lambert Glacier-Amery Ice Shelf System (LAS) Using Remote Sensing." Thesis, 2012. http://hdl.handle.net/1969.1/148137.
Повний текст джерелаWohlleben, Trudy Monique Heidi. "Ice-atmosphere interactions in the Canadian high Arctic: implications for the thermo-mechanical evolution of terrestrial ice masses." Phd thesis, 2009. http://hdl.handle.net/10048/415.
Повний текст джерелаDonoghue, SL. "Changes in the morphology, mass balance, and dynamics of Brown Glacier, Heard Island, with comparison to the surrounding sub-Antarctic islands." Thesis, 2009. https://eprints.utas.edu.au/19886/1/whole_DonoghueShavawnLesley2009_thesis.pdf.
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