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Abstract
The Arctic’s winter water cycle is rapidly changing, with implications for snow moisture sources and transport processes. Stable isotope values (δ18O, δ2H, d-excess) of the Arctic snowpack have potential to provide proxy records of these processes, yet it is unclear how well the isotope values of individual snowfall events are preserved within snow profiles. Here, we present water isotope data from multiple taiga and tundra snow profiles sampled in Arctic Alaska and Finland, respectively, during winter 2018–2019. We compare the snowpack isotope stratigraphy with meteoric water isotopes (vapor and precipitation) during snowfall days, and combine our measurements with satellite observations and reanalysis data. Our analyses indicate that synoptic-scale atmospheric circulation and regional sea ice coverage are key drivers of the source, amount, and isotopic composition of Arctic snowpacks. We find that the western Arctic tundra snowpack profiles in Alaska preserved the isotope values for the most recent storm; however, post depositional processes modified the remaining isotope profiles. The overall seasonal evolution in the vapor isotope values were better preserved in taiga snow isotope profiles in the eastern Arctic, where there is significantly less wind-driven redistribution than in the open Alaskan tundra. We demonstrate the potential of the seasonal snowpack to provide a useful proxy for Arctic winter-time moisture sources and propose future analyses.
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2
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Madsen MV, Steen‐Larsen HC, Hörhold M, Box J, Berben SMP, Capron E, Faber A, Hubbard A, Jensen MF, Jones TR, Kipfstuhl S, Koldtoft I, Pillar HR, Vaughn BH, Vladimirova D, Dahl‐Jensen D. Evidence of Isotopic Fractionation During Vapor Exchange Between the Atmosphere and the Snow Surface in Greenland. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2019; 124:2932-2945. [PMID: 31218150 PMCID: PMC6559289 DOI: 10.1029/2018jd029619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 01/21/2019] [Accepted: 02/09/2019] [Indexed: 06/09/2023]
Abstract
Several recent studies from both Greenland and Antarctica have reported significant changes in the water isotopic composition of near-surface snow between precipitation events. These changes have been linked to isotopic exchange with atmospheric water vapor and sublimation-induced fractionation, but the processes are poorly constrained by observations. Understanding and quantifying these processes are crucial to both the interpretation of ice core climate proxies and the formulation of isotope-enabled general circulation models. Here, we present continuous measurements of the water isotopic composition in surface snow and atmospheric vapor together with near-surface atmospheric turbulence and snow-air latent and sensible heat fluxes, obtained at the East Greenland Ice-Core Project drilling site in summer 2016. For two 4-day-long time periods, significant diurnal variations in atmospheric water isotopologues are observed. A model is developed to explore the impact of this variability on the surface snow isotopic composition. Our model suggests that the snow isotopic composition in the upper subcentimeter of the snow exhibits a diurnal variation with amplitudes in δ18O and δD of ~2.5‰ and ~13‰, respectively. As comparison, such changes correspond to 10-20% of the magnitude of seasonal changes in interior Greenland snow pack isotopes and of the change across a glacial-interglacial transition. Importantly, our observation and model results suggest, that sublimation-induced fractionation needs to be included in simulations of exchanges between the vapor and the snow surface on diurnal timescales during summer cloud-free conditions in northeast Greenland.
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Affiliation(s)
- M. V. Madsen
- Centre for Ice and ClimateUniversity of CopenhagenCopenhagenDenmark
| | - H. C. Steen‐Larsen
- Centre for Ice and ClimateUniversity of CopenhagenCopenhagenDenmark
- Geophysical Institute and Bjerknes Centre for Climate ResearchUniversity of BergenBergenNorway
| | - M. Hörhold
- Alfred‐Wegener‐InstituteBremerhavenGermany
| | | | - S. M. P. Berben
- Department of Earth ScienceUniversity of Bergen and Bjerknes Centre for Climate ResearchBergenNorway
| | - E. Capron
- Centre for Ice and ClimateUniversity of CopenhagenCopenhagenDenmark
- British Antarctic SurveyCambridgeUK
| | - A.‐K. Faber
- Geophysical Institute and Bjerknes Centre for Climate ResearchUniversity of BergenBergenNorway
- Department of Earth ScienceUniversity of Bergen and Bjerknes Centre for Climate ResearchBergenNorway
| | - A. Hubbard
- Centre for Glaciology, Department of Geography and Earth SciencesAberystwyth UniversityAberystwythUK
- Centre for Arctic Gas Hydrate, Environment and Climate, Department of GeologyUiT‐The Arctic University of NorwayTromsøNorway
| | - M. F. Jensen
- Department of Earth ScienceUniversity of Bergen and Bjerknes Centre for Climate ResearchBergenNorway
| | - T. R. Jones
- INSTAARUniversity of Colorado BoulderBoulderCOUSA
| | | | - I. Koldtoft
- Centre for Ice and ClimateUniversity of CopenhagenCopenhagenDenmark
| | - H. R. Pillar
- Oden Institute for Computational Engineering and SciencesUniversity of Texas at AustinAustinTXUSA
| | - B. H. Vaughn
- INSTAARUniversity of Colorado BoulderBoulderCOUSA
| | - D. Vladimirova
- Centre for Ice and ClimateUniversity of CopenhagenCopenhagenDenmark
| | - D. Dahl‐Jensen
- Centre for Ice and ClimateUniversity of CopenhagenCopenhagenDenmark
- Centre for Earth Observation ScienceUniversity of ManitobaWinnipegManitobaCanada
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3
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Wang X, Meijer HAJ. Ice-liquid isotope fractionation factors for 18O and 2H deduced from the isotopic correction constants for the triple point of water. ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2018; 54:304-311. [PMID: 29448822 DOI: 10.1080/10256016.2018.1435533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/17/2018] [Indexed: 06/08/2023]
Abstract
The stable isotopes of water are extensively used as tracers in many fields of research. For this use, it is essential to know the isotope fractionation factors connected to various processes, the most important of which being phase changes. Many experimental studies have been performed on phase change fractionation over the last decades. Whereas liquid-vapour fractionation measurements are relatively straightforward, vapour-solid and liquid-solid fractionation measurements are more complicated, as maintaining equilibrium conditions when a solid is involved is difficult. In this work, we determine the ice-liquid isotope fractionation factors in an indirect way, by applying the Van't Hoff equation. This equation describes the relationship of the fractionation factors with isotope-dependent temperature changes. We apply it to the recently experimentally determined isotope dependences of the triple point temperature of water [Faghihi V, Peruzzi A, Aerts-Bijma AT, et al. Accurate experimental determination of the isotope effects on the triple point temperature of water. I. Dependence on the 2H abundance. Metrologia. 2015;52:819-826; Faghihi V, Kozicki M, Aerts-Bijma AT, et al. Accurate experimental determination of the isotope effects on the triple point temperature of water. II. Combined dependence on the 18O and 17O abundances. Metrologia. 2015;52:827-834]. This results in new values for the 2H (deuterium) and 18O fractionation factors for the liquid-solid phase change of water, which agree well with existing, direct experimental data [Lehmann M, Siegenthaler U. Equilibrium oxygen- and hydrogen-isotope fractionation between ice and water. J Glaciol. 1991;37:23-26]. For 2H, the uncertainty is improved by a factor of 3, whereas for 18O the uncertainty is similar. Our final results are αS-L (2H/1H) = 1.02093(13), and αS-L (18O/16O) = 1.002909(25), where the latter is the weighted average of the previous experimental study and this work.
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Affiliation(s)
- Xing Wang
- a Centre for Isotope Research (CIO), Energy and Sustainability Research Institute Groningen , University of Groningen , Groningen , The Netherlands
| | - Harro A J Meijer
- a Centre for Isotope Research (CIO), Energy and Sustainability Research Institute Groningen , University of Groningen , Groningen , The Netherlands
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Ala‐aho P, Tetzlaff D, McNamara JP, Laudon H, Kormos P, Soulsby C. Modeling the isotopic evolution of snowpack and snowmelt: Testing a spatially distributed parsimonious approach. WATER RESOURCES RESEARCH 2017; 53:5813-5830. [PMID: 28983132 PMCID: PMC5601190 DOI: 10.1002/2017wr020650] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 06/18/2017] [Indexed: 06/07/2023]
Abstract
Use of stable water isotopes has become increasingly popular in quantifying water flow paths and travel times in hydrological systems using tracer-aided modeling. In snow-influenced catchments, snowmelt produces a traceable isotopic signal, which differs from original snowfall isotopic composition because of isotopic fractionation in the snowpack. These fractionation processes in snow are relatively well understood, but representing their spatiotemporal variability in tracer-aided studies remains a challenge. We present a novel, parsimonious modeling method to account for the snowpack isotope fractionation and estimate isotope ratios in snowmelt water in a fully spatially distributed manner. Our model introduces two calibration parameters that alone account for the isotopic fractionation caused by sublimation from interception and ground snow storage, and snowmelt fractionation progressively enriching the snowmelt runoff. The isotope routines are linked to a generic process-based snow interception-accumulation-melt model facilitating simulation of spatially distributed snowmelt runoff. We use a synthetic modeling experiment to demonstrate the functionality of the model algorithms in different landscape locations and under different canopy characteristics. We also provide a proof-of-concept model test and successfully reproduce isotopic ratios in snowmelt runoff sampled with snowmelt lysimeters in two long-term experimental catchment with contrasting winter conditions. To our knowledge, the method is the first such tool to allow estimation of the spatially distributed nature of isotopic fractionation in snowpacks and the resulting isotope ratios in snowmelt runoff. The method can thus provide a useful tool for tracer-aided modeling to better understand the integrated nature of flow, mixing, and transport processes in snow-influenced catchments.
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Affiliation(s)
- Pertti Ala‐aho
- Northern Rivers Institute, School of GeosciencesUniversity of AberdeenAberdeenUK
| | - Doerthe Tetzlaff
- Northern Rivers Institute, School of GeosciencesUniversity of AberdeenAberdeenUK
| | | | - Hjalmar Laudon
- Department of Forest, Ecology and ManagementSwedish University of Agricultural SciencesUmeåSweden
| | - Patrick Kormos
- United States Department of AgricultureAgricultural Research ServiceBoiseIdahoUSA
| | - Chris Soulsby
- Northern Rivers Institute, School of GeosciencesUniversity of AberdeenAberdeenUK
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5
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Laboratory measurements of HDO/H 2O isotopic fractionation during ice deposition in simulated cirrus clouds. Proc Natl Acad Sci U S A 2017; 114:5612-5617. [PMID: 28495968 DOI: 10.1073/pnas.1618374114] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The stable isotopologues of water have been used in atmospheric and climate studies for over 50 years, because their strong temperature-dependent preferential condensation makes them useful diagnostics of the hydrological cycle. However, the degree of preferential condensation between vapor and ice has never been directly measured at temperatures below 233 K (-40 °C), conditions necessary to form cirrus clouds in the Earth's atmosphere, routinely observed in polar regions, and typical for the near-surface atmospheric layers of Mars. Models generally assume an extrapolation from the warmer experiments of Merlivat and Nief [Merlivat L, Nief G (1967) Tellus 19:122-127]. Nonequilibrium kinetic effects that should alter preferential partitioning have also not been well characterized experimentally. We present here direct measurements of HDO/H2O equilibrium fractionation between vapor and ice ([Formula: see text]) at cirrus-relevant temperatures, using in situ spectroscopic measurements of the evolving isotopic composition of water vapor during cirrus formation experiments in a cloud chamber. We rule out the recent proposed upward modification of [Formula: see text], and find values slightly lower than Merlivat and Nief. These experiments also allow us to make a quantitative validation of the kinetic modification expected to occur in supersaturated conditions in the ice-vapor system. In a subset of diffusion-limited experiments, we show that kinetic isotope effects are indeed consistent with published models, including allowing for small surface effects. These results are fundamental for inferring processes on Earth and other planets from water isotopic measurements. They also demonstrate the utility of dynamic in situ experiments for studying fractionation in geochemical systems.
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Galewsky J, Steen-Larsen HC, Field RD, Worden J, Risi C, Schneider M. Stable isotopes in atmospheric water vapor and applications to the hydrologic cycle. REVIEWS OF GEOPHYSICS (WASHINGTON, D.C. : 1985) 2016; 54:809-865. [PMID: 32661517 PMCID: PMC7357203 DOI: 10.1002/2015rg000512] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The measurement and simulation of water vapor isotopic composition has matured rapidly over the last decade, with long-term datasets and comprehensive modeling capabilities now available. Theories for water vapor isotopic composition have been developed by extending the theories that have been used for the isotopic composition of precipitation to include a more nuanced understanding of evaporation, large-scale mixing, deep convection, and kinetic fractionation. The technologies for in-situ and remote sensing measurements of water vapor isotopic composition have developed especially rapidly over the last decade, with discrete water vapor sampling methods, based on mass spectroscopy, giving way to laser spectroscopic methods and satellite- and ground-based infrared absorption techniques. The simulation of water vapor isotopic composition has evolved from General Circulation Model (GCM) methods for simulating precipitation isotopic composition to sophisticated isotope-enabled microphysics schemes using higher-order moments for water- and ice-size distributions. The incorporation of isotopes into GCMs has enabled more detailed diagnostics of the water cycle and has led to improvements in its simulation. The combination of improved measurement and modeling of water vapor isotopic composition opens the door to new advances in our understanding of the atmospheric water cycle, in processes ranging from the marine boundary layer, through deep convection and tropospheric mixing, and into the water cycle of the stratosphere. Finally, studies of the processes governing modern water vapor isotopic composition provide an improved framework for the interpretation of paleoclimate proxy records of the hydrological cycle.
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Affiliation(s)
- Joseph Galewsky
- Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico, USA
| | | | - Robert D Field
- NASA Goddard Institute for Space Studies, New York, New York, USA
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York, USA
| | - John Worden
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Camille Risi
- Laboratoire de Meteorologie Dynamique, Institut Pierre Simon Laplace, Centre National de la Recherche Scientifique, Paris, France
| | - Matthias Schneider
- Institute for Meteorology and Climate Research (IMK-ASF), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
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Cheng B, Behler J, Ceriotti M. Nuclear Quantum Effects in Water at the Triple Point: Using Theory as a Link Between Experiments. J Phys Chem Lett 2016; 7:2210-2215. [PMID: 27203358 DOI: 10.1021/acs.jpclett.6b00729] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
One of the most prominent consequences of the quantum nature of light atomic nuclei is that their kinetic energy does not follow a Maxwell-Boltzmann distribution. Deep inelastic neutron scattering (DINS) experiments can measure this effect. Thus, the nuclear quantum kinetic energy can be probed directly in both ordered and disordered samples. However, the relation between the quantum kinetic energy and the atomic environment is a very indirect one, and cross-validation with theoretical modeling is therefore urgently needed. Here, we use state of the art path integral molecular dynamics techniques to compute the kinetic energy of hydrogen and oxygen nuclei in liquid, solid, and gas-phase water close to the triple point, comparing three different interatomic potentials and validating our results against equilibrium isotope fractionation measurements. We will then show how accurate simulations can draw a link between extremely precise fractionation experiments and DINS, therefore establishing a reliable benchmark for future measurements and providing key insights to increase further the accuracy of interatomic potentials for water.
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Affiliation(s)
- Bingqing Cheng
- Laboratory of Computational Science and Modelling, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Jörg Behler
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum , 44801 Bochum, Germany
| | - Michele Ceriotti
- Laboratory of Computational Science and Modelling, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
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Berkelhammer M, Noone DC, Steen-Larsen HC, Bailey A, Cox CJ, O'Neill MS, Schneider D, Steffen K, White JWC. Surface-atmosphere decoupling limits accumulation at Summit, Greenland. SCIENCE ADVANCES 2016; 2:e1501704. [PMID: 27386509 PMCID: PMC4928998 DOI: 10.1126/sciadv.1501704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 03/31/2016] [Indexed: 06/06/2023]
Abstract
Despite rapid melting in the coastal regions of the Greenland Ice Sheet, a significant area (~40%) of the ice sheet rarely experiences surface melting. In these regions, the controls on annual accumulation are poorly constrained owing to surface conditions (for example, surface clouds, blowing snow, and surface inversions), which render moisture flux estimates from myriad approaches (that is, eddy covariance, remote sensing, and direct observations) highly uncertain. Accumulation is partially determined by the temperature dependence of saturation vapor pressure, which influences the maximum humidity of air parcels reaching the ice sheet interior. However, independent proxies for surface temperature and accumulation from ice cores show that the response of accumulation to temperature is variable and not generally consistent with a purely thermodynamic control. Using three years of stable water vapor isotope profiles from a high altitude site on the Greenland Ice Sheet, we show that as the boundary layer becomes increasingly stable, a decoupling between the ice sheet and atmosphere occurs. The limited interaction between the ice sheet surface and free tropospheric air reduces the capacity for surface condensation to achieve the rate set by the humidity of the air parcels reaching interior Greenland. The isolation of the surface also acts to recycle sublimated moisture by recondensing it onto fog particles, which returns the moisture back to the surface through gravitational settling. The observations highlight a unique mechanism by which ice sheet mass is conserved, which has implications for understanding both past and future changes in accumulation rate and the isotopic signal in ice cores from Greenland.
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Affiliation(s)
- Max Berkelhammer
- Department of Earth and Environmental Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA.; Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.; Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO 80309, USA
| | - David C Noone
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.; Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO 80309, USA.; College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Hans Christian Steen-Larsen
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.; Laboratoire des Sciences du Climat et de l'Environnement, UMR CEA-CNRS-UVSQ/IPSL 8212, Gif-sur-Yvette, France.; Center for Ice and Climate, University of Copenhagen, Copenhagen, Denmark
| | - Adriana Bailey
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.; Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO 80309, USA.; Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, Seattle, WA 98195, USA
| | - Christopher J Cox
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.; Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO 80309, USA.; National Oceanic and Atmospheric Administration, Boulder, CO 80305, USA
| | - Michael S O'Neill
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.; National Oceanic and Atmospheric Administration, Boulder, CO 80305, USA
| | - David Schneider
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.; National Center for Atmospheric Research, Boulder, CO 80305, USA
| | - Konrad Steffen
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.; Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - James W C White
- Department of Geological Sciences, University of Colorado, Boulder, CO 80309, USA.; Environmental Studies Program, University of Colorado, Boulder, CO 80309, USA.; Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, USA
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