A multicomponent coupled model of glacier hydrology 2. A distinctive fungal community inhabiting cryoconite holes. Rapid accelerations of antarctic peninsula outlet glaciers. 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. Links between shortterm velocity variations and the subglacial hydrology of a predominantly cold polythermal glacier. 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. Coupling between glacier hydrology and ice flow may hasten glacier melting. Icecored moraine degradation mapped and quantified using.
The whole mass of any glacier is at zero centigrade or below cryotic, except for nonice inclusions at the glacier surface. Two different types of polythermal svalbard glaciers were chosen. Polythermal glacier regimes are a common, characteristic response in regions with protracted subfreezing winter air temperatures where. The first models of glacier hydrology were developed to quantify glacier. A large body of glacial ice astride a mountain, mountain range, or volcano is termed an ice cap or ice field. Recent progress in understanding marineterminating arctic. The hydrology of mountain glaciers has direct implications for water resources, flood risks, hydropower, ice dynamics and. Structure and changing dynamics of a polythermal valley. 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. Hodgkins, r 1997 glacier hydrology in svalbard, norwegian high. A thermal regime model for polythermal glaciers written by olivier gagliardini.
Polythermal some parts of the glacier are cold, some temperate. Polythermal glaciers, svalbard department of geography. Pdf the hydrology of glaciers concerns the transfer of meltwater through an ice mass. Thermal structure of svalbard glaciers and implications. Application of a polythermal threedimensional ice sheet. A separate trajectory of model development was motivated by the recognition that the retention, evacuation and. Murray t, glasser nf, hubbard a, hubbard b, stuart g, et al. 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. Mapping thermal and hydrological conditions beneath a polythermal glacier with radioecho sounding.
The ice is polythermal, hence below the melting point. The department carries out research and development activities, as well as commissioned work, and is also responsible for. Role of discrete water recharge from supraglacial drainage. A glacier that fills a valley is called a valley glacier, or alternatively an alpine glacier or mountain glacier. Glaciers act as natural reservoirs for snow, ice, and meltwater. 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. Polythermal glacier hydrology and ice flow dynamics. The department carries out research and development activities, as well as commissioned work, and is also responsible for the national flood warning service. Thermodynamics of glaciers mccarthy summer school 2012 andyaschwanden universityofalaskafairbanks,usa. Seasonal variation of drainage system in the lower ablation area. 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. Mechanics and thermodynamics of polythermal glaciers a dissertation submitted to the eth zurich for the degree of doctor of sciences. Therefore, if glacial ice is considered a monomineral rock, then any glacier constitutes a perennially cryotic ground i.
Subglacial drainage system evolution of some mountain glaciers is. Polim also implements the schoofhewitt water transportation scheme in temperate ice and a cavitysheet subglacial hydrology model. The coupling between polar glacier hydrology and dynamics has the potential. Vertical distribution of water within the polythermal. 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 melting of snow and ice creates networks of meltwater streams and ponds on glacier and icesheet surfaces 1,2,3. 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. The thermal regime of the glacier was polythermal in 2010 based on our interpretation of gpr groundpenetrating radar profiles presented by saintenoy et al. 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. Two different types of polythermal svalbard glaciers were. These observations have invigorated the development of new subglacial drainage models. However, the interplay of factors governing its spatial and temporal variations such as. Surface meltwater is known to influence the dynamics of many glaciers 4,5,6,7.
The surface of a glacier consists of seasonal snow, multiyear firn, and glacial ice. Sphy spatial processes in hydrology futurewater pdf. Glacier hydrology is the study of the flow of water through glaciers. Mechanics and thermodynamics of polythermal glaciers. On seasonal time scales, ice melt and temporary meltwater storage within a glacier lead to large amounts of latesummer discharge.
This commentary critically evaluates concepts of extending the term permafrost to any parts of an active glacier. Us environmental protection agency storm water management software the saint. 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. However, much of the contemporary knowledge relating to glacier hydrology has been based upon, and conditioned by, understanding gleaned from temperate valley glaciers. If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. 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. An englacial hydrologic system of brine within a cold.
Polim implements an enthalpybased thermal model which is particularly convenient to simulate the dynamics of polythermal glaciers. On many glaciers, water flowing from the glaciers surface is the main source of supply. In this work, two discontinuities are investigated in more detail. Thermodynamical and hydrological discontinuities in. Study site john evans glacier is a polythermal valley glacier on the east coast of ellesmere island, nunavut, canada 7940n, 743ow. Modelling water flow under glaciers and ice sheets. Structure and changing dynamics of a polythermal valley glacier on a centennial timescale.
Firn is present in the upper accumulation area, where it can be tens of metres thick. The glacier in our study area has a 20 m thick cold, water. An integrated lightweight icepenetrating radar system. Mapping thermal and hydrological conditions beneat h a polythe rmal glacier with radioecho sounding article pdf available in journal of glaciology 47157. Glaciologists believe that many glaciers in svalbard are polythermal, i. Pdf mapping thermal and hydrological conditions beneath. Possible interactions between bacterial diversity, microbial activity and supraglacial hydrology of cryoconite holes in svalbard. The polythermal structure has major implications for glacier hydrology, ice. In theory, firn can be found everywhere above the glaciers equilibrium line altitude ela, increasing in thickness with altitude.
It is considered to be polythermal because the upper portion of the glacier is below the freezing. Coreh2o a dual frequency radar satellite for cold regions pdf. Evidence for seasonal subglacial outburst events at a polythermal glacier. Abstract polythermal glaciers exhibit various thermodynamical and hydrological discontinuities. Modelling water flow under glaciers and ice sheets ncbi. Globally, a significant proportion of glaciers and ice sheets exhibit nontemperate thermal. Drainagesystem development in consecutive melt seasons at. Environmental control of thermal regime on polythermal. Regine hock computed the digital slope and aspect models and provided generous support along with her software. Pdf contribution of snow and glacier melt to discharge for pdf. Environmental control of thermal regime on polythermal glaciers in changing climate earth sciences bibliographies in harvard style. Ice caps have an area less than 50,000 km 2 19,000 sq mi by definition. Theme glaciers and ice sheets store vast quantities of fresh water, and their hydrology is of wideranging importance. Polythermal glacier studies in svalbard determined by.
Mapping and interpretation of bedreflection power from a surgetype polythermal glacier, yukon, canada. The hydrology department at nve has more than 100 employees and is responsible for collecting, storing and analysing data. Measurements at polythermal john evans glacier, ellesmere island, indicate strong links between spatial and temporal variations in subglacial hydrology and changes in surface velocity. Hydrology and dynamics of a polythermal mostly cold high arctic. Mapping and interpretation of bedreflection power from a. The search for seismic signatures of movement at the.
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