Modelling the Impact of Surface Melt on the Hydrology and Dynamics of the Greenland Ice Sheet

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (16 download)

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Book Synopsis Modelling the Impact of Surface Melt on the Hydrology and Dynamics of the Greenland Ice Sheet by : Conrad Pawel Koziol

Download or read book Modelling the Impact of Surface Melt on the Hydrology and Dynamics of the Greenland Ice Sheet written by Conrad Pawel Koziol and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Melt Water Retention Processes in Snow and Firn on Ice Sheets and Glaciers: Observations and Modeling

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Publisher : Frontiers Media SA
ISBN 13 : 2889456196
Total Pages : 160 pages
Book Rating : 4.8/5 (894 download)

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Book Synopsis Melt Water Retention Processes in Snow and Firn on Ice Sheets and Glaciers: Observations and Modeling by : W. Tad Pfeffer

Download or read book Melt Water Retention Processes in Snow and Firn on Ice Sheets and Glaciers: Observations and Modeling written by W. Tad Pfeffer and published by Frontiers Media SA. This book was released on 2018-11-08 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Melt takes place where the surface of glaciers or ice sheets interacts with the atmosphere. While the processes governing surface melt are fairly well understood, the pathways of the meltwater, from its origin to the moment it leaves a glacier system, remain enigmatic. It is not even guaranteed that meltwater leaves a glacier or ice sheet. On Greenland, for example, only slightly more than 50% of the meltwater runs off. The remainder mostly refreezes within the so-called firn cover of the ice sheet. This eBook contains 11 studies which tackle the challenge of understanding meltwater retention in snow and firn from various angles. The studies focus both on mountain glaciers and on the Greenland ice sheet and address challenges such as measuring firn properties, quantifying their influence on meltwater retention, modelling firn processes and meltwater refreezing as well as unravelling the mechanisms within the recently discovered Greenland firn aquifers.

Fundamentals of Glacier Dynamics, Second Edition

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Publisher : CRC Press
ISBN 13 : 1439835667
Total Pages : 407 pages
Book Rating : 4.4/5 (398 download)

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Book Synopsis Fundamentals of Glacier Dynamics, Second Edition by : C.J. van der Veen

Download or read book Fundamentals of Glacier Dynamics, Second Edition written by C.J. van der Veen and published by CRC Press. This book was released on 2013-03-26 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measuring, monitoring, and modeling technologies and methods changed the field of glaciology significantly in the 14 years since the publication of the first edition of Fundamentals of Glacier Dynamics. Designed to help readers achieve the basic level of understanding required to describe and model the flow and dynamics of glaciers, this second edition provides a theoretical framework for quantitatively interpreting glacier changes and for developing models of glacier flow. See What’s New in the Second Edition: Streamlined organization focusing on theory, model development, and data interpretation Introductory chapter reviews the most important mathematical tools used throughout the remainder of the book New chapter on fracture mechanics and iceberg calving Consolidated chapter covers applications of the force-budget technique using measurements of surface velocity to locate mechanical controls on glacier flow The latest developments in theory and modeling, including the addition of a discussion of exact time-dependent similarity solutions that can be used for verification of numerical models The book emphasizes developing procedures and presents derivations leading to frequently used equations step by step to allow readers to grasp the mathematical details as well as physical approximations involved without having to consult the original works. As a result, readers will have gained the understanding needed to apply similar techniques to somewhat different applications. Extensively updated with new material and focusing more on presenting the theoretical foundations of glacier flow, the book provides the tools for model validation in the form of analytical steady-state and time-evolving solutions. It provides the necessary background and theoretical foundation for developing more realistic ice-sheet models, which is essential for better integration of data and observations as well as for better model development.

Influence of Meltwater on Greenland Ice Sheet Dynamics

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ISBN 13 :
Total Pages : 220 pages
Book Rating : 4.:/5 (1 download)

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Book Synopsis Influence of Meltwater on Greenland Ice Sheet Dynamics by : Laura A. Stevens

Download or read book Influence of Meltwater on Greenland Ice Sheet Dynamics written by Laura A. Stevens and published by . This book was released on 2017 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seasonal fluxes of meltwater control ice-flow processes across the Greenland Ice Sheet ablation zone and subglacial discharge at marine-terminating outlet glaciers. With the increase in annual ice sheet meltwater production observed over recent decades and predicted into future decades, understanding mechanisms driving the hourly to decadal impact of meltwater on ice flow is critical for predicting Greenland Ice Sheet dynamic mass loss. This thesis investigates a wide range of meltwater-driven processes using empirical and theoretical methods for a region of the western margin of the Greenland Ice Sheet. I begin with an examination of the seasonal and annual ice flow record for the region using in situ observations of ice flow from a network of Global Positioning System (GPS) stations. Annual velocities decrease over the seven-year time-series at a rate consistent with the negative trend in annual velocities observed in neighboring regions. Using observations from the same GPS network, I next determine the trigger mechanism for rapid drainage of a supraglacial lake. In three consecutive years, I find precursory basal slip and uplift in the lake basin generates tensile stresses that promote hydrofracture beneath the lake. As these precursors are likely associated with the introduction of meltwater to the bed through neighboring moulin systems, our results imply that lakes may be less able to drain in the less crevassed, interior regions of the ice sheet. Expanding spatial scales to the full ablation zone, I then use a numerical model of subglacial hydrology to test whether model-derived effective pressures exhibit the theorized inverse relationship with melt-season ice sheet surface velocities. Finally, I pair near-ice fjord hydrographic observations with modeled and observed subglacial discharge for the Saqqardliup sermia–Sarqardleq Fjord system. I find evidence of two types of glacially modified waters whose distinct properties and locations in the fjord align with subglacial discharge from two prominent subcatchments beneath Saqqardliup sermia. Continued observational and theoretical work reaching across discipline boundaries is required to further narrow our gap in understanding the forcing mechanisms and magnitude of Greenland Ice Sheet dynamic mass loss.

The Impact of Melting Ice on the Ecosystems in Greenland Sea

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Publisher : Springer
ISBN 13 : 3642544983
Total Pages : 93 pages
Book Rating : 4.6/5 (425 download)

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Book Synopsis The Impact of Melting Ice on the Ecosystems in Greenland Sea by : Bo Qu

Download or read book The Impact of Melting Ice on the Ecosystems in Greenland Sea written by Bo Qu and published by Springer. This book was released on 2014-10-09 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: Arctic marine ecosystems are largely impacted by changes associated with global warming. The sea ice in Greenland Sea plays an important role in regional and global climate system. The book investigate the relationships between phytoplankton biomass, measured using remotely sensed chlorophyll-a (CHL), aerosol optical depth (AOD) and sea-ice cover (ICE) in the Greenland Sea (20°W-10°E, 65-85°N) over the period 2003-2012. First hand Satellite data was used to do correlation analysis. Enhanced statistics methods, such as lag regression method and cointegration analysis method are used for correlation and regression analysis between 2 variables (up to 3 variables). ARMA model was used to prediction time series in the future 3 years. The book not only gives outline of ecosystem in Greenland Sea, how the ice impact to the local ecosystems, but also provides valuable statistical methods on analysis correlations and predicting the future ecosystems.

Hydrologic Dynamics of the Greenland Ice Sheet from Remote Sensing and Field Measurements

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ISBN 13 :
Total Pages : 221 pages
Book Rating : 4.:/5 (926 download)

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Book Synopsis Hydrologic Dynamics of the Greenland Ice Sheet from Remote Sensing and Field Measurements by : Vena Chu

Download or read book Hydrologic Dynamics of the Greenland Ice Sheet from Remote Sensing and Field Measurements written by Vena Chu and published by . This book was released on 2015 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: The current need for forecasting Greenland Ice Sheet contributions to global sea level rise is complicated by the lack of understanding of ice sheet hydrology. The proportion of meltwater contributing to sea level rise, as well as the pathways transporting meltwater on, through, and out of the ice sheet, are not well understood. Remote sensing of hydrologic dynamics in combination with small-scale fieldwork allows examination of broad spatial and temporal trends in the Greenland hydrologic system responding to a changing climate. This dissertation reviews the current state of knowledge on Greenland Ice Sheet hydrology, and examines three components of the Greenland hydrologic system: (1) fjord sediment plumes as an indicator of meltwater output, (2) supraglacial streamflow as an indicator of meltwater input to the ice sheet, and (3) moulin distribution and formation as a mechanism diverting meltwater from the surface of the ice sheet to the bed. Buoyant sediment plumes that develop in fjords downstream of outlet glaciers are controlled by numerous factors, including meltwater runoff. MODIS retrievals of sediment plume concentration show a strong regional and seasonal response to meltwater production on the ice sheet surface, despite limitations in fjords with rapidly calving glaciers, providing a tool for tracking meltwater release to the ocean. Summertime field observations and high-resolution satellite imagery reveal extensive supraglacial river networks across the southwestern ablation zone transporting large volumes of meltwater to moulins, yet these features remain poorly mapped and their discharges unquantified. A GIS modeling framework is developed to spatially adapt Manning's equation for use with high-resolution WorldView-2 imagery to map supraglacial river discharge. Moulins represent connections between surface meltwater on the Greenland ice sheet and subglacial drainage networks, where increased meltwater can enhance ice sliding dynamics. A new high-resolution moulin dataset in western Greenland created from WorldView-1/2 imagery in the 2012 record melt year is used to assess moulin distribution and formation. Moulin locations show a significantly different distribution compared to geospatial variables in the entire study area, with moulins forming in areas of thinner ice, higher velocity and extensional strain rate, as well as lower surface elevation and slope, and higher bed elevation and slope.

Greenland Ice Sheet Hydrology and Dynamics

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (19 download)

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Book Synopsis Greenland Ice Sheet Hydrology and Dynamics by : Adam Igneczi

Download or read book Greenland Ice Sheet Hydrology and Dynamics written by Adam Igneczi and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

The Influence of Meltwater on the Thermal Structure and Flow of the Greenland Ice Sheet

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ISBN 13 :
Total Pages : 152 pages
Book Rating : 4.:/5 (945 download)

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Book Synopsis The Influence of Meltwater on the Thermal Structure and Flow of the Greenland Ice Sheet by : Kristin Poinar

Download or read book The Influence of Meltwater on the Thermal Structure and Flow of the Greenland Ice Sheet written by Kristin Poinar and published by . This book was released on 2015 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the climate has warmed over the past decades, the amount of melt on the Greenland Ice Sheet has increased, and areas higher on the ice sheet have begun to melt regularly. This increase in melt has been hypothesized to enhance ice flow in myriad ways, including through basal lubrication and englacial refreezing. By developing and interpreting thermal ice-sheet models and analyzing remote sensing data, I evaluate the effect of these processes on ice flow and sea-level rise from the Greenland Ice Sheet. I first develop a thermal ice sheet model that is applicable to western Greenland. Key components of this model are its treatment of multiple phases (solid ice and liquid water) and its viscosity-dependent velocity field. I apply the model to Jakobshavn Isbræ, a fast-flowing outlet glacier. This is an important benchmark for my model, which I next apply to the topics outlined above. I use the thermal model to calculate the effect of englacial latent-heat transfer (meltwater refreezing within englacial features such as firn and crevasses) on ice dynamics in western Greenland. I find that in slow-moving areas, this can significantly warm the ice, but that englacial latent heat transfer has only a minimal effect on ice motion (10%). By contrast, in fast-flowing regions, which contribute most (60%) of the ice flux into the ocean, evidence of deep englacial warming is virtually absent. Thus, the effects of englacial latent heat transfer on ice motion are likely limited to slow-moving regions, which limits its importance to ice-sheet mass balance. Next, I couple a model for ice fracture to a modified version of my thermal model to calculate the depth and shape evolution of water-filled crevasses that form in crevasse fields. At most elevations and for typical water input volumes, crevasses penetrate to the top ~200–300 meters depth, warm the ice there by ~10°C, and may persist englacially, in a liquid state, for multiple decades. The surface hydrological network limits the amount of water that can reach most crevasses. We find that the depth and longevity of such crevasses is relatively robust to realistic increases in melt volumes over the coming century, so that we should not expect large changes in the englacial hydrological system under near-future climate regimes. These inferences put important constraints on the timescales of the Greenland supraglacial-to-subglacial water cycle. Finally, I assess the likelihood that higher-elevation surface melt could deliver water to regions where the bed is currently frozen. This hypothetical process is important because it could potentially greatly accelerate the seaward motion of the ice sheet. By analyzing surface strain rates and comparing them to my modeled basal temperature field, I find that this scenario is unlikely to occur: the conditions necessary to form surface-to-bed conduits are rarely found at higher elevations (~1600 meters) that may overlie frozen beds.

Greenland Ice Sheet Change: Surface Climate Variability and Glacier Dynamics

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ISBN 13 :
Total Pages : 160 pages
Book Rating : 4.:/5 (637 download)

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Book Synopsis Greenland Ice Sheet Change: Surface Climate Variability and Glacier Dynamics by : Lei Yang

Download or read book Greenland Ice Sheet Change: Surface Climate Variability and Glacier Dynamics written by Lei Yang and published by . This book was released on 2007 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: The co-variability of glacier ice discharges and climate variability is also examined by using Polar MM5 V1 modeled summer temperature and April-September Positive Degree Day (PDD) anomalies. Ice discharges from south Greenland glaciers are found to be sensitive to temperature change. Based on sensitivities of ice discharge to melt index anomalies, time series of total ice discharge from 28 major glaciers since 1958 are modeled. The global sea level rise contribution from Greenland ice sheet during past 50 years is estimated be ∼0.6 mm yr-1 in average.

Modeling and Measuring Water Level Fluctuations in the Greenland Ice Sheet

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ISBN 13 :
Total Pages : 344 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Modeling and Measuring Water Level Fluctuations in the Greenland Ice Sheet by : Celia Trunz

Download or read book Modeling and Measuring Water Level Fluctuations in the Greenland Ice Sheet written by Celia Trunz and published by . This book was released on 2021 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the ablation zone of land terminating sectors of the Greenland Ice Sheet (GrIS), water pressures at the bed control ice motion variability on diurnal and seasonal timescales. During the melt season, large volumes of surface meltwater access the ice-bed interface through moulins.Moulins are large vertical shafts that connect the supraglacial and subglacial drainage systems. Moulins form when a crevasse intersects a surface meltwater source that can drive hydrofracture to the bed of the ice sheet. Upon reaching the bed, meltwater can establish and sustain an efficient, channelized drainage system. Due to the technical impossibility of physically exploring underwater passages beneath the GrIS, the subglacial drainage system must be studied through geophysical methods. To date, measurements of water level variability within moulins and boreholes have proved to be critical for constraining models. However, direct hydrologic measurements from the GrIS are sparse, due to the remoteness and harsh conditions of the ice sheet. The work presented in this dissertation combines simple physically based mathematical models with direct measurements from the ablation portion of Sermeq Avannarleq, in west Greenland to advance our understanding of the influence of moulin geometry and life span on glacier dynamics. In Chapter 2, I investigate the moulin life cycle within several neighboring surface catchments within the GrIS ablation zone. A combination of remote sensing and ground observations of moulin locations over two to three years reveals an annual pattern of systematic formation and abandonment of moulins after they are advected down-glacier.In Chapter 3, I use a modified single conduit model to explore the role of moulin shape and size on hydraulic head variability within moulins. This model shows that only the englacial storage capacity within the range of water level fluctuations affects the oscillation range of moulin hydraulic head, which controls subglacial channel water pressure dynamics. Further, the model shows that depth-varying changes in englacial water storage control the temporal shape of the head oscillations. Finally, in Chapter 4, I simulate the moulin water level variability in a moulin we instrumented in 2017-2018 using the recently developed Moulin Shape (MouSh) model. The MouSh model requires additional subglacial baseflow to simulate an accurate diurnal range of head oscillation. We hypothesize that this additional baseflow is the result of strong network connectivity with other moulins through a channelized subglacial drainage system, potentially supplemented by basal or non-local, upstream inputs. Additional work is necessary to accurately characterize moulin positions and life cycles, and to determine whether the observed annual formation and abandonment is widespread. Such characterization would improve the simulation of moulin inputs in models. In addition, further knowledge of the shape of moulins around the equilibrium head elevation would improve englacial storage parameterization in subglacial hydrological models and aid predictions of coupling between meltwater and ice motion under future melt scenarios. Finally, this work suggests that the connectivity of the subglacial network needs further study, to improve our understanding on how local and non-local drivers influence subglacial water pressures and ice sliding.

Vogel, Manfred, 1946-

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Publisher :
ISBN 13 :
Total Pages : 236 pages
Book Rating : 4.:/5 (735 download)

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Book Synopsis Vogel, Manfred, 1946- by :

Download or read book Vogel, Manfred, 1946- written by and published by . This book was released on 1961 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: The folder may include clippings, announcements, small exhibition catalogs, and other ephemeral items.

Fundamentals of Glacier Dynamics

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Publisher : CRC Press
ISBN 13 : 9789054104704
Total Pages : 472 pages
Book Rating : 4.1/5 (47 download)

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Book Synopsis Fundamentals of Glacier Dynamics by : C.J.van der Veen

Download or read book Fundamentals of Glacier Dynamics written by C.J.van der Veen and published by CRC Press. This book was released on 1999-01-01 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals of Glacier Dynamics presents an introduction to modelling the flow and dynamics of glaciers. The emphasis is more on developing and outlining procedures than on providing a complete overview of all aspects of glacier dynamics. Derivations leading to frequently-used equations are presented step-by-step to allow the reader to grasp the mathematical details and approximations involved and gain the understanding needed to apply similar concepts to different applications. The first four chapters discuss the background and theory needed for glacier modelling. The central part of the book discusses simple analytical solutions and time-evolving numerical models that are used to study general aspects of glacier dynamics and important feedback mechanisms. The final three chapters discuss applications specific to smaller mountain glaciers, the Greenland Ice Sheet, and the Antarctic Ice Sheet, respectively. This book will be suitable for graduate courses in geophysics and will also serve as a reference volume for scientists active in all aspects of glaciology and related research. Standard undergraduate mathematics and physics are sufficient background for studying the text.

Satellite Investigations of Ice Dynamics and Supraglacial Lake Development in Greenland

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ISBN 13 :
Total Pages : 174 pages
Book Rating : 4.:/5 (827 download)

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Book Synopsis Satellite Investigations of Ice Dynamics and Supraglacial Lake Development in Greenland by : Kate Hannah Briggs

Download or read book Satellite Investigations of Ice Dynamics and Supraglacial Lake Development in Greenland written by Kate Hannah Briggs and published by . This book was released on 2012 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis aims to improve the current understanding of the processes which control the flow variability of Greenland Ice Sheet (GrIS) outlet glaciers. The most recent Intergovernmental Governmental Panel on Climate Change (IPCC) report (Meehl et al., 2007) identifies that a critical limitation to forecasts of sea-level rise are uncertainties in modelling the ice dynamics of the GrIS. Using Synthetic Aperture Radar (SAR) feature tracking, seasonal velocities of land- and marine- terminating glaciers in a region in the northeast of Greenland are measured. Records of air temperature in conjunction with seasonal observations of supraglacial lake development, sea ice conditions and ice front positions, derived from SAR imagery, are used to investigate the controls on the observed variations in ice velocity. A clear link between ice velocities and glacier hydrology is found. These findings are consistent with observations from other glaciers in Greenland and are suggestive of a universal hydrological forcing of ice velocity for the whole of the GrIS ablation zone. Lake drainage events have been identified as a key factor in linking atmospheric changes, glacier hydrology and ice velocities in Greenland. For modelling purposes, a means of parameterising the distribution and evolution of supraglacial lakes is therefore needed. Assuming that water will pond in surface depressions, this thesis assesses the ability of using Digital Elevation Models (DEMs) for this purpose. High resolution DEMs are created using Interferometric SAR (InSAR) for two, separate regions of the GrIS. The positions and areal extent of surface depressions are compared with those of lakes observed in optical satellite imagery. The level of correspondence between the two datasets is found to be poor as a result of the resolution of the DEMs and the physical differences between surface depressions and lakes (e.g. lakes may not fill the capacity of the depression). An alternative method for parameterising the seasonal distribution of supra-glacial lakes, by extrapolating trends observed in current lake distributions, is investigated. The locations and evolution of lakes in the west of Greenland during the summer of 2003 are mapped using 47 Moderate Resolution Imaging Spectroradiometer (MODIS) images. Clear trends are identified in the distributions of lakes with elevation and are linked to the seasonal melt-cycle and to changes in ice thickness and its influence on surface depressions, tensile stresses and hydrofracturing. It may be possible to extrapolate these trends to other regions and higher elevations on the ice sheet, thereby enabling the distribution of lakes to be parameterised in ice sheet models. The findings of this thesis help to contribute to the understanding of the interaction between climate and ice dynamics in the context of the GrIS.

Mapping Greenland Supraglacial Melt Lakes and the Role of Local- and Synoptic-scale Climates in Their Variations

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (915 download)

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Book Synopsis Mapping Greenland Supraglacial Melt Lakes and the Role of Local- and Synoptic-scale Climates in Their Variations by : Nathan Amador

Download or read book Mapping Greenland Supraglacial Melt Lakes and the Role of Local- and Synoptic-scale Climates in Their Variations written by Nathan Amador and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: My doctoral research utilizes remote sensing and GIS techniques to evaluate the influence of climate on the surface hydrology of the Greenland Ice Sheet. Specifically, I assess changes in supraglacial melt lake spatial and temporal patterns in the ablation zone (or melt zone) along the ice sheet margin around Jakobshavn Isbræ. Supraglacial melt lakes play a significant role in ice sheet hydrology and mass balance as they have the propensity to catastrophically drain. Such episodic drainage events inject surface meltwater to the ice sheet--bedrock interface, lubricating the bed, and provide a mechanism for a dynamic response in ice flow. The contribution of Greenland's outlet glaciers to sea level rise has doubled over the last two decades due to this increased calving.I introduce a novel tool, FoveaPro (a plug-in to Adobe Photoshop), for mapping supraglacial melt lakes in the ablation zone from satellite imagery. FoveaPro allows the user to semi-automate supraglacial lake mapping, making lake identification more time efficient, and to generate more-precise spatial statistics (such as melt lake area and shape) on these lakes than current manual methods. I identify atmospheric circulation patterns coincident with anomalously high and low melt periods in the context of a 13-year climatology. I utilize depth-reflectancealgorithms that have been previously developed for this region, to calculate melt lake volume. To ensure accuracy of the melt lake volume calculations, the results were compared with estimates from a degree-day model that utilizes data from a nearby weather station in the ablation zone, and with satellite-derived digital elevation models (DEMs). A more thorough understanding of the amount of surface meltwater stored in supraglacial lakes, and its atmospheric drivers, better constrains its impacts on ice sheet hydrology and consequent ice sheet contribution to global sea level rise.

The Ocean and Cryosphere in a Changing Climate

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Publisher : Cambridge University Press
ISBN 13 : 1009178466
Total Pages : 1807 pages
Book Rating : 4.0/5 (91 download)

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Book Synopsis The Ocean and Cryosphere in a Changing Climate by : Intergovernmental Panel on Climate Change (IPCC)

Download or read book The Ocean and Cryosphere in a Changing Climate written by Intergovernmental Panel on Climate Change (IPCC) and published by Cambridge University Press. This book was released on 2022-05-19 with total page 1807 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for assessing the science related to climate change. It provides policymakers with regular assessments of the scientific basis of human-induced climate change, its impacts and future risks, and options for adaptation and mitigation. This IPCC Special Report on the Ocean and Cryosphere in a Changing Climate is the most comprehensive and up-to-date assessment of the observed and projected changes to the ocean and cryosphere and their associated impacts and risks, with a focus on resilience, risk management response options, and adaptation measures, considering both their potential and limitations. It brings together knowledge on physical and biogeochemical changes, the interplay with ecosystem changes, and the implications for human communities. It serves policymakers, decision makers, stakeholders, and all interested parties with unbiased, up-to-date, policy-relevant information. This title is also available as Open Access on Cambridge Core.

Bare Ice Hydrologic Processes on the Greenland Ice Sheet Ablation Zone

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Publisher :
ISBN 13 :
Total Pages : 230 pages
Book Rating : 4.:/5 (119 download)

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Book Synopsis Bare Ice Hydrologic Processes on the Greenland Ice Sheet Ablation Zone by : Matthew Cooper

Download or read book Bare Ice Hydrologic Processes on the Greenland Ice Sheet Ablation Zone written by Matthew Cooper and published by . This book was released on 2020 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Greenland Ice Sheet is a major contributor to global sea level rise, with recent mass loss dominated by meltwater runoff from the ablation zone, i.e. areas of the ice sheet where annual mass losses exceed gains. In this zone, the winter snowpack melts entirely each summer exposing bare glacier ice. Observations of Greenland's ablation zone suggest the exposed bare ice surface is comprised of low-density ice termed "weathering crust" that may store meltwater, potentially reducing meltwater runoff export to surrounding oceans. Climate models are the primary tools used to forecast future Greenland mass loss, but these models treat the ablation zone as impermeable high-density ice with no meltwater retention capacity. Recent evidence suggests that climate models overpredict meltwater runoff from the ablation zone, which may be linked to weathering crust presence, but diagnosing climate model predictions is difficult because observations of meltwater runoff on the ice sheet surface are extremely rare and weathering crust presence is undocumented. This dissertation presents the results of four investigations that address this problem by pairing field observations of hydrologic and radiative properties of bare ice collected in Greenland's ablation zone with numerical modeling and analysis of climate model output. The results of these investigations reveal the presence of low-density weathering crust on Greenland's bare ice ablation zone surface and the potential for non-trivial meltwater runoff retention within weathering crust on Greenland's bare ice ablation zone surface. New estimates of spectral radiation attenuation coefficients are quantified and directly applied to a numerical model of spectral and thermodynamic heat transfer in bare ice. This model successfully simulates meltwater runoff from a supraglacial catchment on Greenland's southwest ablation zone surface. Model results suggest that nocturnal refreezing of meltwater stored within weathering crust occurs in Greenland's ablation zone, potentially reducing runoff up to 32% on annual timescales. These findings imply a reinterpretation of refreezing on bare ice as an important control on Greenland's ablation zone surface mass balance and the need to represent this process in climate model predictions of future Greenland mass loss.

Ice Sheets and Climate

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Publisher : Springer
ISBN 13 : 9789027717092
Total Pages : 232 pages
Book Rating : 4.7/5 (17 download)

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Book Synopsis Ice Sheets and Climate by : Johannes Oerlemans

Download or read book Ice Sheets and Climate written by Johannes Oerlemans and published by Springer. This book was released on 1984-02-29 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discusses the specific role ice sheets play in the climate system, at a level suitable for post-graduate courses. Includes mathematical models.