Ninth International Conference on Permafrost ... - IARC Research

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Phase Changes of Water as a Basis of the Water and Energy Exchange Function ofthe CryosphereV.V. ShepelevMelnikov Permafrost Institute, SB RAS, Yakutsk, RussiaWater exists on our planet in all three of its phases withinthe temperature and pressure ranges found on Earth, resultingin very high activity and extent of phase transitions of water.This involves intensive phase interaction of water, that is,water transfer from the liquid state to the gaseous state andback, from the solid state to the gaseous or liquid state, etc.Many authors emphasized the importance of the interphaseform of water movement. Priklonsky (1958), in his generalcharacterization of groundwater formation, consideredsuch phase changes as evaporation and freezing to be themain types of water movement in the ground. Khodkov &Valukonis (1968), in their discussion of the main types ofmovement of natural waters, ranked the phase transition ofwater above other forms of water movement or migration.It is this form of water movement that Vernadsky (1960)had in mind, suggesting the existence of the phase field ofthe Earth, which encompasses the upper lithosphere andthe near-surface atmosphere. The necessity of applying thetheoretical knowledge on water physics to investigations ofglobal water cycles was underlined by Sokolov (1966). Henoted, in particular, that the role of the cryosphere as a waterexchangesystem is very high, though remains little studied.Research on interphase interactions of water is complicatedby the fact that all the basic states of water are not phasehomogeneous,but phase-heterogeneous. In other words, thephase mixing effect is inherent in water. In the atmosphere,water is present in liquid, solid, and gaseous states. Similarly,surface ice and ice-rich permafrost contain some amounts ofthe liquid and gas forms of water. The phase heterogeneityof the basic states of water can be explained by the fact thatin nature, there exists no absolutely pure water in either ofthe states—liquid, solid, or gas. Water in any macroscopicvolume is, above all, a dispersion medium in whichvarious microscopic impurities, such as mineral, organicand other solid particles and compounds, are dispersed.The high surface energy of these microscopic particlescauses the formation of water microphases on their surface,which intensively exchange water with the surroundingmacroscopic medium, determining to a large measure itswater- and energy-exchange function.In the ground, the microscopic phase dispersion of wateris boosted, so to say, by the mechanical dispersion of thesoil. For example, pellicular water in the zone of aerationis a liquid microphase of water, which actively exchangeswater and interacts with the surrounding pore air medium.Similarly, unfrozen interfacial water in ice-rich permafrostcan be considered a liquid microphase of water which is indynamic equilibrium with the pore ice medium. This explains,among other factors, the well-known concept of equilibriumunfrozen water content in frozen ground (Tsytovich 1945,1959). This concept implies that the unfrozen water contentin frozen ground varies with changes in temperature andexternal pressure of soil or rock. Phase changes of unfrozenwater to ice and back occur even under very slight changesin ground temperature or external pressure.Hence the basic physical states of water reflect onlyits macroscopic phase homogeneity, characterizing oneor another phase of bulk water as a continuum. From themicroscopic point of view, the main physical states ofwater are phase heterogeneous, and this drives the waterand energy exchange and other important processes in theEarth’s atmosphere, hydrosphere, lithosphere, and, certainly,cryosphere.Considering the crucial role the phase changes andphase interactions of water play in the cryosphere, and inorder to quantify the water and energy exchange functionof the cryosphere, it is proposed that the global cyclesin climatic circulation of water are distinguished asfollows: cryoatmogenic, cryohydrogenic, atmolithogenic,glaciogenic, and cryolithogenic (Table 1).The cryoatmogenic cycle is related to sublimation of watervapour in the atmosphere, that is, the phase changes of waterfrom gas to solid and back, and subsequent falling on theearth surface as large snow and ice formations.The cryohydrogenic cycle is driven by the formation ofseasonal river ice, lake ice, icings, and ground ice in theactive layer of permafrost and the subsequent melting ofthese seasonal ice forms, as well as snow cover.The atmolithogenic cycle involves evaporation,condensation and sublimation of water in the zone ofaeration, which can be viewed as subsurface atmosphereand where intensive moisture transfer occurs, linking theatmosphere and the lithosphere.The glaciogenic and cryolithogenic cycles are caused bylong-term, rather than seasonal, climatic fluctuations. In coldperiods, the solid phase of water in glaciers and permafrostincreases in volume and mass. Conversely, in warm periods,liquid water resources increase due to melting of glaciers andground ice. Hence the glaciogenic and cryolithogenic cyclesTable 1. Characteristics of the cryosphere as a water and energyexchange system.Main water andenergy cyclesMass of waterinvolved in annualwater cycle, kgEnergy released (+)or taken up (-), WtCryoatmogenic 1.0 · 10 13 ± 0.9 · 10 12Cryohydrogenic 2.6 · 10 16 ± 2.75 · 10 14Atmolithogenic 0.2 · 10 11 ± 0.18 · 10 10Glaciogenic 0.25 · 10 16 - 2.6 · 10 14Cryolithogenic 2.5 · 10 13 - 0.26 · 10 12283
Ni n t h In t e r n at i o n a l Co n f e r e n c e o n Pe r m a f r o s thave a trend effect on the annual balance of the liquid phaseof natural waters, causing a long-term decrease or increasein their volume and sea level.For quantitative comparison of the cycles identified above,the mass of water involved annually in each water-exchangecycle and the thermal energy released or taken up duringthe changes in state of water have been estimated based onavailable information (see Table 1). It should be noted that thewater-exchange functions of some of these cycles are as yetlittle understood and poorly quantified. This is particularlytrue for the cryoatmogenic and atmolithogenic cycles, thusrequiring the establishment of special-purpose research andobservation programs to obtain more reliable estimates. Asfor the rest of the cycles, the quantitative characterization oftheir water- and energy-exchange function has been basedon the analysis of relatively representative data.The values presented in the table indicate the crucial roleof the cryosphere in the global water and energy budget,allowing us to call it a fluctuating cryogenic phase shell ofour planet. Further investigations of the water- and energyexchange function of the cryosphere in this perspectivewill contribute to a better understanding of the role of thecryosphere in total global exchange of energy and matter,and help detect the changes in these processes due to naturalfactors and human impacts.AcknowledgmentsThe author would like to thank Larisa Fedorova and LiliaProkopieva, Melnikov Permafrost Institute, for assistance inpreparation of this manuscript.ReferencesKhodkov, A.E. & Valukonis, G.Y. 1968. The Formation andGeological Role of Groundwater. Leningrad: Izd-voLeningradskogo Universiteta, 216 pp.Priklonsky, V.A. 1958. Basic experimental issues ingroundwater formation research. In: Transactions ofthe Laboratory of Hydrogeological Problems, Vol.XVI. Moscow: Izd-vo AN SSSR, 86-105.Sokolov, B.L. 1996. New results of experimental investigationon the lithogenic component of river runoff. VodnyeResursy 23(3): 278-287.Tsytovich, N.A. 1945. On the theory of equilibrium stateof water in frozen ground. Izvestia AN SSSR, SeriaGeograficheskaya 5–6: 61-67.Tsytovich, N.A. 1959. Physical processes and phenomenain freezing, frozen and thawing soils. In: ThePrinciples of Geocryology (Permafrost Studies). PartI. Permafrost Science. Moscow: Izd-vo AN SSSR,108-152.Vernadsky, V.I. 1960. Selected Papers. Vol. 4, Book 2.Moscow: Izd-vo AN SSSR, 651 pp.284
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ContentsPreface ...................
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Mapping and Modeling the Distributi
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Satellite Observations of Frozen Gr
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xiiIce Wedge Thermal Regime in Nort
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xivPermafrost Response to Dynamics
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NICOP SponsorsUniversitiesUniversit
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Deep Permafrost Studies at the Lupi
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Effect of Fire on Pond Dynamics in
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Cryological Status of Russian Soils
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Acoustical Surveys of Methane Plume
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Permafrost Delineation Near Fairban
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Preparatory Work for a Permanent Ge
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A Provisional Soil Map of the Trans
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Martian Permafrost Depths from Orbi
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Time Series Analyses of Active Micr
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Impact of Permafrost Degradation on
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DC Resistivity Soundings Across a P
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Modeling Thermal and Moisture Regim
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A Provisional Permafrost Map of the
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Alpine Permafrost Distribution at M
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Cryogenic Formations of the Caucasu
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Modeling Potential Climatic Change
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A Hypothesis: A Condition of Growth
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Modeled Continual Surface Water Sto
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Freeze/Thaw Properties of Tundra So
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Discontinuous Permafrost Distributi
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Thermal Regime Within an Arctic Was
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Seasonal and Interannual Variabilit
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Twelve-Year Thaw Progression Data f
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Continued Permafrost Warming in Nor
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Landsliding Following Forest Fire o
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A Permafrost Model Incorporating Dy
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Seasonal Sources of Soil Respiratio
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Greenland Permafrost Temperature Si
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The Importance of Snow Cover Evolut
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The Account of Long-Term Air Temper
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The Combined Isotopic Analysis of L
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Adaptating and Managing Nunavik’s
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Human Experience of Cryospheric Cha
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HiRISE Observations of Fractured Mo
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A Soil Freeze-Thaw Model Through th
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Mapping and Modeling the Distributi
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First Results of Ground Surface Tem
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Historical Changes in the Seasonall
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Rock Glaciers in the Kåfjord Area,
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Snowpack Evolution on Permafrost, N
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Climate Change in Permafrost Region
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Maximizing Construction Season in a
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Pleistocene Sand-Wedge, Composite-W
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370Huang, B. 339Hugelius, G. 105, 1
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