Ice caps have an area less than 50,000 km 2 19,000 sq mi by definition. If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Hodgkins, r 1997 glacier hydrology in svalbard, norwegian high. Vertical distribution of water within the polythermal.
Possible interactions between bacterial diversity, microbial activity and supraglacial hydrology of cryoconite holes in svalbard. On seasonal time scales, ice melt and temporary meltwater storage within a glacier lead to large amounts of latesummer discharge. Analysis of the thermal and mechanical response of high altitude glaciers to climate change is crucial to assess future glacier hazards associated with thermal regime changes. A glacier that fills a valley is called a valley glacier, or alternatively an alpine glacier or mountain glacier. In this work, two discontinuities are investigated in more detail. Structure and changing dynamics of a polythermal valley glacier on a centennial timescale. Glaciers act as natural reservoirs for snow, ice, and meltwater. Drainagesystem development in consecutive melt seasons at.
Recent progress in understanding marineterminating arctic. Study site john evans glacier is a polythermal valley glacier on the east coast of ellesmere island, nunavut, canada 7940n, 743ow. Pdf mapping thermal and hydrological conditions beneath. Thermal structure of svalbard glaciers and implications. Glacier hydrology is the study of the flow of water through glaciers. Glacier volume changes since the little ice age maximum and consequences for stream flow by integrating models of glacier flow and hydrology in the cordillera blanca, peruvian. The search for seismic signatures of movement at the.
Mapping and interpretation of bedreflection power from a surgetype polythermal glacier, yukon, canada. Two different types of polythermal svalbard glaciers were. Environmental control of thermal regime on polythermal glaciers in changing climate earth sciences bibliographies in harvard style. It is a mysterious world, where water running on the surface of the glacier disappears through cracks and holes in the glaciers, and powerful rivers emerge from the glacier snout1. The coupling between polar glacier hydrology and dynamics has the potential. The glacier in our study area has a 20 m thick cold, water. Application of a polythermal threedimensional ice sheet. The distinctive feature of this model is the detailed consideration of the basal temperate ice layer, in which the water content and its impact on the ice viscosity are. Mapping and interpretation of bedreflection power from a. Pdf the hydrology of glaciers concerns the transfer of meltwater through an ice mass. Structure and changing dynamics of a polythermal valley.
On many glaciers, water flowing from the glaciers surface is the main source of supply. The search for seismic signatures of movement at the glacier bed in a polythermal valley glacier joseph pomeroy, 1 alex brisbourne, 2 jeffrey evans, 1 david graham 1 1 polar and alpine research centre, department of geography, loughborough university, loughborough, uk email. The hydrology department at nve has more than 100 employees and is responsible for collecting, storing and analysing data. Mechanics and thermodynamics of polythermal glaciers. Evidence for seasonal subglacial outburst events at a polythermal glacier.
However, the interplay of factors governing its spatial and temporal variations such as. That is, it is mostly composed of temperate ice with the exception of a cold surface layer in the ablation zone and lower accumulation zone. These observations have invigorated the development of new subglacial drainage models. However, much of the contemporary knowledge relating to glacier hydrology has been based upon, and conditioned by, understanding gleaned from temperate valley glaciers. Role of discrete water recharge from supraglacial drainage. Surface meltwater is known to influence the dynamics of many glaciers 4,5,6,7. Links between shortterm velocity variations and the subglacial hydrology of a predominantly cold polythermal glacier. Coreh2o a dual frequency radar satellite for cold regions pdf.
We collected three groups of res transects, a group proximal to blood falls within 80 m, a mid group farther upglacier 100160 m, and a distal group 800 m upglacier from blood falls, in order to constrain the full extent and geometry of the bed and any englacial brine. Glaciologists believe that many glaciers in svalbard are polythermal, i. Environmental control of thermal regime on polythermal. In theory, firn can be found everywhere above the glaciers equilibrium line altitude ela, increasing in thickness with altitude. Polythermal glacier regimes are a common, characteristic response in regions with protracted subfreezing winter air temperatures where. Firn is present in the upper accumulation area, where it can be tens of metres thick. Seasonal variation of drainage system in the lower ablation area. It is considered to be polythermal because the upper portion of the glacier is below the freezing. Pdf contribution of snow and glacier melt to discharge for pdf. The thermal regime of the glacier was polythermal in 2010 based on our interpretation of gpr groundpenetrating radar profiles presented by saintenoy et al. The surface of a glacier consists of seasonal snow, multiyear firn, and glacial ice. Modelling water flow under glaciers and ice sheets. Through the upsurge in interest in polythermal glacier hydrology, coupled with the recent developments in data acquisition and theoretical developments, and similarities alluded to here, sharp et al. Modelling water flow under glaciers and ice sheets ncbi.
A thermal regime model for polythermal glaciers written by olivier gagliardini. Globally, a significant proportion of glaciers and ice sheets exhibit nontemperate thermal. Us environmental protection agency storm water management software the saint. The diversity of highly active bacterial communities in cryoconite holes on three arctic glaciers in svalbard was investigated using terminal restriction fragment length polymorphism trflp of. Rapid accelerations of antarctic peninsula outlet glaciers. Murray t, glasser nf, hubbard a, hubbard b, stuart g, et al.
The department carries out research and development activities, as well as commissioned work, and is also responsible for the national flood warning service. Theme glaciers and ice sheets store vast quantities of fresh water, and their hydrology is of wideranging importance. Therefore, if glacial ice is considered a monomineral rock, then any glacier constitutes a perennially cryotic ground i. A multicomponent coupled model of glacier hydrology 2. Measurements at polythermal john evans glacier, ellesmere island, indicate strong links between spatial and temporal variations in subglacial hydrology and changes in surface velocity. The hydrology of mountain glaciers has direct implications for water resources, flood risks, hydropower, ice dynamics and. The polythermal structure has major implications for glacier hydrology, ice.
Box 3000, fin90014 university of oulu, finland oulu, finland 2003 abstract the overall aim of this thesis is to emphasise how ground penetrating radar gpr can be used in. In contrast with the ml and vb glaciers both of which are polythermal, containing ice both below and at the pressure melting point, ab is a cold glacier comprising only ice below the pressure melting point and the resulting ice dynamics may have a role in dictating surface slopes and icesurface hydrology. Polythermal glacier hydrology and ice flow dynamics. The first models of glacier hydrology were developed to quantify glacier. Occurs with warmbased glaciers and portions of polythermal glaciers underlain by a soft bed strain response of sediment beneath glacier to stress of overlying ice. Coupling between glacier hydrology and ice flow may hasten glacier melting. A separate trajectory of model development was motivated by the recognition that the retention, evacuation and. This commentary critically evaluates concepts of extending the term permafrost to any parts of an active glacier. Polythermal glacier studies in svalbard determined by.
Icecored moraine degradation mapped and quantified using. An englacial hydrologic system of brine within a cold. Yet there is a need to improve understanding of polythermal glacier hydrology in particular, since nontemperate ice ice below the pressuremelting temperature, lacking interstitial water is commonly encountered in highlatitude ice masses irvinefynn et al. Regine hock computed the digital slope and aspect models and provided generous support along with her software. An integrated lightweight icepenetrating radar system. The department carries out research and development activities, as well as commissioned work, and is also responsible for. Abstract polythermal glaciers exhibit various thermodynamical and hydrological discontinuities.
The melting of snow and ice creates networks of meltwater streams and ponds on glacier and icesheet surfaces 1,2,3. Polim implements an enthalpybased thermal model which is particularly convenient to simulate the dynamics of polythermal glaciers. Polim also implements the schoofhewitt water transportation scheme in temperate ice and a cavitysheet subglacial hydrology model. The whole mass of any glacier is at zero centigrade or below cryotic, except for nonice inclusions at the glacier surface. Mapping thermal and hydrological conditions beneath a polythermal glacier with radioecho sounding. Polythermal glaciers, svalbard department of geography. Sphy spatial processes in hydrology futurewater pdf. Mapping thermal and hydrological conditions beneat h a polythe rmal glacier with radioecho sounding article pdf available in journal of glaciology 47157. A large body of glacial ice astride a mountain, mountain range, or volcano is termed an ice cap or ice field. Abstract steadystate and transient climatechange computations are performed with the authors threedimensional polythermal ice sheet model simulation code for polythermal ice sheets for the greenland ice sheet. Subglacial drainage system evolution of some mountain glaciers is. Mechanics and thermodynamics of polythermal glaciers a dissertation submitted to the eth zurich for the degree of doctor of sciences.
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