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Zannoni D, Steen‐Larsen HC, Peters AJ, Wahl S, Sodemann H, Sveinbjörnsdóttir AE. Non-Equilibrium Fractionation Factors for D/H and 18O/ 16O During Oceanic Evaporation in the North-West Atlantic Region. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2022; 127:e2022JD037076. [PMID: 36582456 PMCID: PMC9786641 DOI: 10.1029/2022jd037076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 10/12/2022] [Accepted: 10/25/2022] [Indexed: 06/17/2023]
Abstract
Ocean isotopic evaporation models, such as the Craig-Gordon model, rely on the description of nonequilibrium fractionation factors that are, in general, poorly constrained. To date, only a few gradient-diffusion type measurements have been performed in ocean settings to test the validity of the commonly used parametrization of nonequilibrium isotopic fractionation during ocean evaporation. In this work, we present 6 months of water vapor isotopic observations collected from a meteorological tower located in the northwest Atlantic Ocean (Bermuda) with the objective of estimating nonequilibrium fractionation factors (k, ‰) for ocean evaporation and their wind speed dependency. The Keeling Plot method and Craig-Gordon model combination were sensitive enough to resolve nonequilibrium fractionation factors during evaporation resulting into mean values of k 18 = 5.2 ± 0.6‰ and k 2 = 4.3 ± 3.4‰. Furthermore, we evaluate the relationship between k and 10-m wind speed over the ocean. Such a relationship is expected from current evaporation theory and from laboratory experiments made in the 1970s, but observational evidence is lacking. We show that (a) in the observed wind speed range [0-10 m s-1], the sensitivity of k to wind speed is small, in the order of -0.2‰ m-1 s for k 18, and (b) there is no empirical evidence for the presence of a discontinuity between smooth and rough wind speed regime during isotopic fractionation, as proposed in earlier studies. The water vapor d-excess variability predicted under the closure assumption using the k values estimated in this study is in agreement with observations over the Atlantic Ocean.
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Affiliation(s)
- D. Zannoni
- Geophysical InstituteUniversity of Bergen and Bjerknes Centre for Climate ResearchBergenNorway
| | - H. C. Steen‐Larsen
- Geophysical InstituteUniversity of Bergen and Bjerknes Centre for Climate ResearchBergenNorway
| | - A. J. Peters
- Bermuda Institute of Ocean SciencesSt. George’sBermuda
| | - S. Wahl
- Geophysical InstituteUniversity of Bergen and Bjerknes Centre for Climate ResearchBergenNorway
| | - H. Sodemann
- Geophysical InstituteUniversity of Bergen and Bjerknes Centre for Climate ResearchBergenNorway
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2
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Kang JH, Hwang H, Lee SJ, Choi SD, Kim JS, Hong S, Hur SD, Baek JH. Record of North American boreal forest fires in northwest Greenland snow. CHEMOSPHERE 2021; 276:130187. [PMID: 33740646 DOI: 10.1016/j.chemosphere.2021.130187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/24/2021] [Accepted: 03/02/2021] [Indexed: 05/16/2023]
Abstract
We present boreal forest fire proxies in a northwest Greenland snowpit spanning a period of six years, from spring 2003 to summer 2009. Levoglucosan (C6H10O5) is a specific organic molecular marker of biomass burning caused by boreal forest fires. In this study, levoglucosan was determined via liquid chromatography/negative ion electrospray ionization-tandem mass spectrometry, wherein isotope-dilution and multiple reaction monitoring methods are employed. Ammonium (NH4+) and oxalate (C2O42-), traditional biomass burning proxies, were determined using two-channel ion chromatography. In the northwest Greenland snowpit, peaks in levoglucosan, ammonium, and oxalate were observed in snow layers corresponding to the summer-fall seasons of 2004 and 2005. Considered together, these spikes are a marker for large boreal forest fires. The levoglucosan deposited in the Greenland snow was strongly dependent on long-range atmospheric transportation. A 10-day backward air mass trajectory analysis supports that the major contributors were air masses from North America. In addition, satellite-derived carbon monoxide (CO) and ammonia (NH3) concentrations suggest that chemicals from North American boreal forest fires during the summer-fall of 2004 and 2005 were transported to Greenland. However, large boreal fires in Siberia in 2003 and 2008 were not recorded in the snowpit. The sub-annual resolution measurements of levoglucosan and ammonium can distinguish between the contributions of past boreal forest fires and soil emissions from anthropogenic activity to Greenland snow and ice.
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Affiliation(s)
- Jung-Ho Kang
- Division of Glacial Environment Research, Korea Polar Research Institute, Incheon, 21990, Republic of Korea.
| | - Heejin Hwang
- Division of Glacial Environment Research, Korea Polar Research Institute, Incheon, 21990, Republic of Korea
| | - Sang-Jin Lee
- School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Sung-Deuk Choi
- School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Jin-Soo Kim
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Sangbum Hong
- Division of Glacial Environment Research, Korea Polar Research Institute, Incheon, 21990, Republic of Korea
| | - Soon Do Hur
- Division of Glacial Environment Research, Korea Polar Research Institute, Incheon, 21990, Republic of Korea
| | - Je-Hyun Baek
- Analysis Service Center, Diatech Korea Co., Ltd., Seoul, 05808, Republic of Korea
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3
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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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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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5
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Global patterns of declining temperature variability from the Last Glacial Maximum to the Holocene. Nature 2018; 554:356-359. [PMID: 29400701 DOI: 10.1038/nature25454] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 12/12/2017] [Indexed: 11/08/2022]
Abstract
Changes in climate variability are as important for society to address as are changes in mean climate. Contrasting temperature variability during the Last Glacial Maximum and the Holocene can provide insights into the relationship between the mean state of the climate and its variability. However, although glacial-interglacial changes in variability have been quantified for Greenland, a global view remains elusive. Here we use a network of marine and terrestrial temperature proxies to show that temperature variability decreased globally by a factor of four as the climate warmed by 3-8 degrees Celsius from the Last Glacial Maximum (around 21,000 years ago) to the Holocene epoch (the past 11,500 years). This decrease had a clear zonal pattern, with little change in the tropics (by a factor of only 1.6-2.8) and greater change in the mid-latitudes of both hemispheres (by a factor of 3.3-14). By contrast, Greenland ice-core records show a reduction in temperature variability by a factor of 73, suggesting influences beyond local temperature or a decoupling of atmospheric and global surface temperature variability for Greenland. The overall pattern of reduced variability can be explained by changes in the meridional temperature gradient, a mechanism that points to further decreases in temperature variability in a warmer future.
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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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Liu J, Xiao C, Ding M, Ren J. Variations in stable hydrogen and oxygen isotopes in atmospheric water vapor in the marine boundary layer across a wide latitude range. J Environ Sci (China) 2014; 26:2266-2276. [PMID: 25458681 DOI: 10.1016/j.jes.2014.09.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 03/31/2014] [Accepted: 04/11/2014] [Indexed: 06/04/2023]
Abstract
The newly-developed cavity ring-down laser absorption spectroscopy analyzer with special calibration protocols has enabled the direct measurement of atmospheric vapor isotopes at high spatial and temporal resolution. This paper presents real-time hydrogen and oxygen stable isotope data for atmospheric water vapor above the sea surface, over a wide range of latitudes spanning from 38°N to 69°S. Our results showed relatively higher values of δ(18)O and δ(2)H in the subtropical regions than those in the tropical and high latitude regions, and also a notable decreasing trend in the Antarctic coastal region. By combining the hydrogen and oxygen isotope data with meteoric water line and backward trajectory model analysis, we explored the kinetic fractionation caused by subsiding air masses and related saturated vapor pressure in the subtropics, and the evaporation-driven kinetic fractionation in the Antarctic region. Simultaneous observations of meteorological and marine variables were used to interpret the isotopic composition characteristics and influential factors, indicating that d-excess is negatively correlated with humidity across a wide range of latitudes and weather conditions worldwide. Coincident with previous studies, d-excess is also positively correlated with sea surface temperature and air temperature (Tair), with greater sensitivity to Tair. Thus, atmospheric vapor isotopes measured with high accuracy and good spatial-temporal resolution could act as informative tracers for exploring the water cycle at different regional scales. Such monitoring efforts should be undertaken over a longer time period and in different regions of the world.
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Affiliation(s)
- Jingfeng Liu
- State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Cunde Xiao
- State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China; Chinese Academy of Meteorological Sciences, Beijing 100081, China
| | - Minghu Ding
- State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China; Chinese Academy of Meteorological Sciences, Beijing 100081, China
| | - Jiawen Ren
- State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
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Buizert C, Gkinis V, Severinghaus JP, He F, Lecavalier BS, Kindler P, Leuenberger M, Carlson AE, Vinther B, Masson-Delmotte V, White JWC, Liu Z, Otto-Bliesner B, Brook EJ. Greenland temperature response to climate forcing during the last deglaciation. Science 2014; 345:1177-80. [PMID: 25190795 DOI: 10.1126/science.1254961] [Citation(s) in RCA: 180] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Greenland ice core water isotopic composition (δ(18)O) provides detailed evidence for abrupt climate changes but is by itself insufficient for quantitative reconstruction of past temperatures and their spatial patterns. We investigate Greenland temperature evolution during the last deglaciation using independent reconstructions from three ice cores and simulations with a coupled ocean-atmosphere climate model. Contrary to the traditional δ(18)O interpretation, the Younger Dryas period was 4.5° ± 2°C warmer than the Oldest Dryas, due to increased carbon dioxide forcing and summer insolation. The magnitude of abrupt temperature changes is larger in central Greenland (9° to 14°C) than in the northwest (5° to 9°C), fingerprinting a North Atlantic origin. Simulated changes in temperature seasonality closely track changes in the Atlantic overturning strength and support the hypothesis that abrupt climate change is mostly a winter phenomenon.
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Affiliation(s)
- Christo Buizert
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA.
| | - Vasileios Gkinis
- Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Denmark. Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, USA
| | - Jeffrey P Severinghaus
- Scripps Institution of Oceanography, University of California-San Diego, La Jolla, CA 92093, USA
| | - Feng He
- Center for Climatic Research, Nelson Institute for Environmental Studies, University of Wisconsin, Madison, WI 53706, USA
| | - Benoit S Lecavalier
- Department of Physics and Physical Oceanography, Memorial University, St. John's, Canada
| | - Philippe Kindler
- Division of Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - Markus Leuenberger
- Division of Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - Anders E Carlson
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Bo Vinther
- Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Denmark
| | - Valérie Masson-Delmotte
- Laboratoire des Sciences du Climat et de l'Environnement, Institut Pierre Simon Laplace (UMR CEA-CNRS-UVSQ 8212), Gif-sur-Yvette, France
| | - James W C White
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, USA
| | - Zhengyu Liu
- Center for Climatic Research, Nelson Institute for Environmental Studies, University of Wisconsin, Madison, WI 53706, USA. Laboratory for Climate and Ocean-Atmosphere Studies, Peking University, Beijing 100871, China
| | - Bette Otto-Bliesner
- Climate and Global Dynamics Division, National Center for Atmospheric Research, Boulder, CO 80307, USA
| | - Edward J Brook
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
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Ellehoj MD, Steen-Larsen HC, Johnsen SJ, Madsen MB. Ice-vapor equilibrium fractionation factor of hydrogen and oxygen isotopes: experimental investigations and implications for stable water isotope studies. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2013; 27:2149-2158. [PMID: 23996388 DOI: 10.1002/rcm.6668] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 06/18/2013] [Accepted: 06/23/2013] [Indexed: 06/02/2023]
Abstract
RATIONALE The equilibrium fractionation factors govern the relative change in the isotopic composition during phase transitions of water. The commonly used results, which were published more than 40 years ago, are limited to a minimum temperature of -33°C. This limits the reliability in cold regions. With recent instrumental developments it is now possible to test the accuracy of the earlier results as well as extend the temperature range. METHODS Novel measurements were made of the ice-vapor equilibrium fractionation factor α between 0°C and -40°C, from a unique experimental setup using both a Picarro cavity ringdown spectrometer and a TC/EA IRMS system. Using both systems allows for continuous monitoring of the equilibrium state of the system as well as testing for reproducibility. RESULTS The results of the experiments show fractionation factors for δ(2) H and δ(18) O values, with a temperature dependency in accordance with theory for equilibrium fractionation. We obtain the following expressions for the temperature dependency of the fractionation coefficients: ln(αδ2H)=0.2133-(203.10/T+(48888/T2 ln(αδ18O)=0.0831-(49.192/T)+(8312.5/T2). Compared with previous experimental work, a significantly larger α for δ(2) H is obtained while, for δ(18) O, α is larger for temperatures below -20°C and slightly lower for temperatures above this. CONCLUSIONS Using the new values for α, a Rayleigh distillation model shows significant changes in both magnitude and shape of an annual deuterium excess signal in Greenland. This emphasizes the importance of a well-defined value of α for accurate studies of the processes in the hydrological cycle and underlines the significance of the differences between the results of this work and earlier work.
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Affiliation(s)
- M D Ellehoj
- Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
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10
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Eemian interglacial reconstructed from a Greenland folded ice core. Nature 2013; 493:489-94. [PMID: 23344358 DOI: 10.1038/nature11789] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 11/13/2012] [Indexed: 11/08/2022]
Abstract
Efforts to extract a Greenland ice core with a complete record of the Eemian interglacial (130,000 to 115,000 years ago) have until now been unsuccessful. The response of the Greenland ice sheet to the warmer-than-present climate of the Eemian has thus remained unclear. Here we present the new North Greenland Eemian Ice Drilling ('NEEM') ice core and show only a modest ice-sheet response to the strong warming in the early Eemian. We reconstructed the Eemian record from folded ice using globally homogeneous parameters known from dated Greenland and Antarctic ice-core records. On the basis of water stable isotopes, NEEM surface temperatures after the onset of the Eemian (126,000 years ago) peaked at 8 ± 4 degrees Celsius above the mean of the past millennium, followed by a gradual cooling that was probably driven by the decreasing summer insolation. Between 128,000 and 122,000 years ago, the thickness of the northwest Greenland ice sheet decreased by 400 ± 250 metres, reaching surface elevations 122,000 years ago of 130 ± 300 metres lower than the present. Extensive surface melt occurred at the NEEM site during the Eemian, a phenomenon witnessed when melt layers formed again at NEEM during the exceptional heat of July 2012. With additional warming, surface melt might become more common in the future.
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11
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Persson A, Langen PL, Ditlevsen P, Vinther BM. The influence of precipitation weighting on interannual variability of stable water isotopes in Greenland. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jd015517] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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12
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Sime LC, Lang N, Thomas ER, Benton AK, Mulvaney R. On high-resolution sampling of short ice cores: Dating and temperature information recovery from Antarctic Peninsula virtual cores. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jd015894] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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Sjolte J, Hoffmann G, Johnsen SJ, Vinther BM, Masson-Delmotte V, Sturm C. Modeling the water isotopes in Greenland precipitation 1959–2001 with the meso-scale model REMO-iso. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jd015287] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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