Atmospheric influences on water stable isotopes in Antarctic water vapor and surface snow – implications for ice core interpretation

2021 ◽  
Author(s):  
Elisabeth Schlosser ◽  
Saeid Bagheri ◽  
Jordan G. Powers ◽  
Kevin W. Manning ◽  
Maria Hoerhold ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Water Vapor ◽  
Stable Isotope ◽  
Ice Cores ◽  
Particle Dispersion ◽  
Back Trajectory ◽  
Meteorological Observatory ◽  
Measuring Period ◽  
Surface Snow ◽  
Snow Samples

<p>In Austral summer 2017/18 daily surface snow samples were taken (weather allowing) at two depths, 0-1cm and 6-7cm, at Neumayer III Station, Dronning Maud Land DML, Antarctica. Stable isotope ratios (18O, D, d-excess) of the snow samples were analysed in the AWI isotope lab. In parallel, water vapor stable isotopes were measured continuously on a routine base with a Picarro cavity ring-down spectroscope analyser (CRDS). Neumayer III is also a full meteorological observatory measuring all important meteorological variables including upper-air data. Meteorological data were directly compared to both snow and vapor isotope data. The corresponding synoptic situations were analysed using data from AMPS (Antarctic Mesoscale Prediction System), which employs WRF (Weather Research and Forecasting Model), a mesoscale atmospheric model that has been successfully used in earlier studies in DML. AMPS is run operationally at NCAR for Antarctic weather forecasting, particularly for flight operations of the US Antarctic Program (USAP). Additionally, back-trajectory calculations to investigate moisture sources and transport were carried out using FLEXPART, an open-source Lagrangian particle dispersion model. Due to logistical problems, the measuring period during the expedition was too short for statistical analysis, thus we focus on case studies here. In particular, periods with no precipitation were investigated, since earlier studies in Greenland have shown that the interaction of snow surface and atmosphere is important for the stable isotope ratio in the snow, thus in later ice cores that are used to derive paleo temperatures. A better understanding of the highly complex relationship between water vapor stable isotopes and meteorological conditions (including moisture source and transport) as well as the interaction between surface snow and water vapor is necessary for a correct paleoclimatic interpretation of ice cores.</p>

scholarly journals Spatial Variability of Glaciochemistry along a Transect from Zhongshan Station to LGB69, Antarctica

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 393
Author(s):  
Weilong Huang ◽  
Ming Yan ◽  
Robert Mulvaney ◽  
Zuoqin Qian ◽  
Leibao Liu ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Source Region ◽  
Methanesulfonic Acid ◽  
Ice Cores ◽  
Sea Salt ◽  
Ion Concentrations ◽  
Zhongshan Station ◽  
Surface Snow ◽  
Coastal Sea ◽  
Snow Samples

The spatial glaciochemical variability of snow samples collected along a transect from Zhongshan Station to Lambert Glacier Basin 69 (LGB69) in Antarctica was investigated. Sea-salt ion concentrations exponentially decreased with increasing distance from the coast and/or altitude. The observed high sea-salt ion concentrations within 20.6 km of the coast may be related to preferential wet or dry deposition of sea-salt aerosols. Methanesulfonic acid (MSA), non-sea-salt sulfate (nssSO42−), and calcium (Ca2+) concentrations decreased along the transect. The mean MSA/nssSO42− value of the surface snow samples (0.34 ± 0.08) indicates that coastal sea areas are their likely source regions. The non-sea-salt Ca2+ (nssCa2+)/Ca2+ percentages of the surface snow and LGB69 snow pit samples reveal that continental dust is the primary Ca2+ source. The δD and δ18O values decreased from the coast inland. The variation of deuterium excess (d-excess) along the transect was stable and d-excess values in the two snow pit samples were low and similar, which indicates that the moisture source region between Zhongshan Station and LGB69 is a coastal sea area. These results reveal the spatial distribution patterns and sources of ions and stable isotopes, as well as factors that influence the deposition of ions and the composition of stable isotopes, which provide important insight for further studies of ice cores drilled in Antarctic coastal regions.

scholarly journals Precipitation regime and stable oxygen isotopes at Dome C, East Antarctica – a comparison of two extreme years 2009 and 2010

2015 ◽  
Vol 15 (21) ◽  
pp. 30473-30509
Author(s):  
E. Schlosser ◽  
B. Stenni ◽  
M. Valt ◽  
A. Cagnati ◽  
J. G. Powers ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Ice Core ◽  
Ice Cores ◽  
Isotope Ratios ◽  
Atmospheric Model ◽  
Stable Isotope Ratios ◽  
Stable Water Isotopes ◽  
Precipitation Regime ◽  
Meridional Transport ◽  
Measuring Period

Abstract. At the East Antarctic deep ice core drilling site Dome C, daily precipitation measurements have been initiated in 2006 and are being continued until today. The amounts and stable isotope ratios of the precipitation samples as well as crystal types are determined. Within the measuring period, the two years 2009 and 2010 showed striking contrasting temperature and precipitation anomalies, particularly in the winter seasons. The reasons for these anomalies and their relation to stable isotope ratios are analysed using data from the mesoscale atmospheric model WRF (Weather Research and Forecasting Model) run under the Antarctic Mesoscale Prediction System (AMPS). 2009 was relatively warm and moist due to frequent warm air intrusions connected to amplification of Rossby waves in the circumpolar westerlies, whereas the winter of 2010 was extremely dry and cold. It is shown that while in 2010 a strong zonal atmospheric flow was dominant, in 2009 an enhanced meridional flow prevailed, which increased the meridional transport of heat and moisture onto the East Antarctic plateau and led to a number of high-precipitation/warming events at Dome C. This was also evident in a positive (negative) SAM index and a negative (positive) ZW3 index during the winter months of 2010 (2009). Changes in the frequency or seasonality of such event-type precipitation can lead to a strong bias in the air temperature derived from stable water isotopes in ice cores.

scholarly journals Using characteristic times to assess whether stable isotopes in polar snow can be reversibly deposited

2002 ◽  
Vol 35 ◽  
pp. 118-124 ◽  
Author(s):  
Edwin D. Waddington ◽  
Eric J. Steig ◽  
Thomas A. Neumann
Keyword(s):  
Boundary Layer ◽  
Stable Isotopes ◽  
Water Vapor ◽  
Accumulation Rate ◽  
Ice Cores ◽  
Isotopic Signature ◽  
Snow Surface ◽  
Atmospheric Water ◽  
Resistor Network ◽  
Polar Snow

AbstractStable isotopes in ice cores are used as a proxy for the temperature at the time of snow formation. Where net accumulation rate is relatively high, snow is buried quickly and initial isotopic values are preserved. However, in low-accumulation areas, snow is exposed to lengthy vapor exchange with the atmosphere. the original isotopic signature of this snow may be modified by equilibration with atmospheric water vapor in the boundary layer over the snow surface in summer. We estimate the characteristic times for equilibration by using an electrical resistor network analogue. Warm, windy summers and low accumulation rate enhance equilibration. Although equilibration of the complete snowpack is unlikely, significant post-depositional change may occur in some Antarctic environments.

scholarly journals Continual in-situ monitoring of pore water stable isotopes in the subsurface

2013 ◽  
Vol 10 (11) ◽  
pp. 13293-13331 ◽  
Author(s):  
T. H. M. Volkmann ◽  
M. Weiler
Keyword(s):  
Stable Isotopes ◽  
Water Vapor ◽  
Stable Isotope ◽  
Monitoring System ◽  
Pore Water ◽  
Sampling Method ◽  
Transport Processes ◽  
In Situ Monitoring ◽  
Subsurface Water

Abstract. The stable isotope signature of pore water provides an integral fingerprint of water origin, flow path, transport processes, and residence times and can thus serve as a powerful tracer of hydrological processes in the unsaturated and saturated zone. However, the full potential of stable isotopes to quantitatively characterize subsurface water dynamics is yet unfolded due to the difficulty in obtaining extensive detailed and continual measurements of spatiotemporally variable pore water signatures. With the development of field-deployable laser-based isotope analyzers, such measurements are now becoming feasible. This study presents the development and application of a functional, automatable, and cost-efficient system for non-destructive continual in-situ monitoring of pore water stable isotope signatures with high resolution. The monitoring system uses automatic-controllable valve arrays to continuously extract diluted soil air water vapor via a branching network of multiple small microporous probes into a commercial isotope analyzer. Soil temperature observations are used to convert obtained vapor phase into liquid phase water isotope signatures, but these can also be obtained based on vapor concentration measurements. In-situ sampling was conducted at six depths for each of three plots planted with varying vegetation on an experimental site in SW Germany. Two different methods based on advective and diffusive soil water vapor probing were employed suitable under unsaturated and all (including saturated) moisture conditions, respectively. The advective sampling method was applied using multiple permanently installed probes (continual mode) and using a single probe subsequently inserted to sample the various locations (push-in mode), while the diffusive sampling method was applied in push-in mode only. Using a specific identical treatment onsite calibration approach along with basic corrections for instrument bias and temperature dependent free water-vapor isotopic equilibrium fractionation, the monitoring system facilitated inference of normalized liquid pore water isotopic composition with sufficiently high accuracy and precision at sampling intervals of less than four minutes and resolved the isotopic variability along natural depth profiles. Comparison indicated that the presented in-situ approaches may be used interchangeably with each other and with concurrent laboratory-based direct equilibration measurements of destructively collected samples, such that the choice of method will depend upon the task and anticipated conditions of sampling. The introduced sampling techniques provide powerful tools towards a detailed quantitative understanding of dynamic and heterogeneous shallow subsurface and vadose zone processes.

scholarly journals Seasonal variations of accumulation and the isotope record in ice cores: a study with surface snow samples and firn cores from Neumayer station, Antarctica

2002 ◽  
Vol 35 ◽  
pp. 97-101 ◽  
Author(s):  
Elisabeth Schlosser ◽  
Hans Oerter
Keyword(s):  
Air Temperature ◽  
Ice Core ◽  
Ice Cores ◽  
Early Spring ◽  
Late Winter ◽  
Short Time Scale ◽  
High Time Resolution ◽  
Water Vapour Diffusion ◽  
Surface Snow ◽  
Snow Samples

AbstractAt the German wintering base Neumayer, an intensive glacio-meteorological programme has been carried out during the last two decades. A complete meteorological dataset and data from surface snow samples, snow pits, firn cores and weekly accumulation measurements from a stake array are available. We first investigated the attenuation of the seasonal δ18O signal due to water-vapour diffusion in the snowpack. A comparison of surface snow samples and firn cores of different ages shows that only one-third of the seasonal δ18O signal of the surface snow samples remains in the cores after the first year. No further significant change in the amplitude of the seasonal δ18O signal is found later. Changes in the seasonal distribution of accumulation can lead to a bias in ice-core properties. This is studied on a short time-scale, using high-time-resolution data of accumulation, stable-isotope ratios and air temperature. Mean annual δ18O values from firn cores are not well correlated to annual mean air temperatures. However, the correlation is improved considerably by calculating an annual mean air temperature using monthly mean temperatures weighted by monthly accumulation. At Neumayer, it is mainly the cyclonic activity in late winter/early spring that determines whether and how the core data are biased.

scholarly journals Stable isotopes in the snow of the coastal areas of Antarctica

2021 ◽  
Vol 65 (4) ◽  
pp. 495-502
Author(s):  
S. V. Kakareka ◽  
T. I. Kukharchyk ◽  
A. A. Ekaykin ◽  
Yu. G. Giginyak
Keyword(s):  
Stable Isotopes ◽  
Isotopic Composition ◽  
Isotope Composition ◽  
Ice Cores ◽  
Statistical Parameters ◽  
Factors Affecting ◽  
Marguerite Bay ◽  
Antarctic Expedition ◽  
First Results ◽  
Snow Samples

The first results of study of stable isotopes of oxygen (δ18O) and hydrogen (δD) in the snow samples taken on the islands of Marguerite Bay (Antarctic Peninsula), in the Vecherny Oasis (Enderby Land), and Larsemann Hills (Princess Elizabeth Land) by the participants of the 12th Belarusian Antarctic Expedition (January–March 2020) are presented. The concentration of water isotopes: deuterium (D) and oxygen-18 (18O) in the samples was determined using a laser isotope composition analyzer Picarro L2130. A total of 32 snow samples were analyzed. The statistical parameters of the isotopic composition of snow were estimated, and the main differences in the content of δ18O and δD between the study areas were shown. A decrease in the content of heavy oxygen and hydrogen isotopes in the newly fallen snow to the old snow of the surface horizons is shown. The maximum values of δ18O and δD are typical for the Maritime Antarctica, decreasing towards the coastal zone and further – towards its continental part. The possible factors affecting the isotope content are described. It is shown that the monitoring of the isotope composition can be an integral part of the monitoring of climatic changes within the area of operation of the Belarusian Antarctic Expedition. The study of the isotopic composition of surface snow is important for the reconstruction of the paleoclimate of the marginal zone of the Antarctic ice sheet based on the ice cores study.

scholarly journals Snow heterogeneous reactivity of bromide with ozone lost during snow metamorphism

2020 ◽  
Author(s):  
Jacinta Edebeli ◽  
Jürg C. Trachsel ◽  
Sven E. Avak ◽  
Markus Ammann ◽  
Martin Schneebeli ◽  
...  
Keyword(s):  
Water Vapor ◽  
Temperature Gradient ◽  
Snow Cover ◽  
Atmospheric Chemistry ◽  
Chemical Reactivity ◽  
Trace Gases ◽  
Heterogeneous Reactivity ◽  
Surface Snow ◽  
Avalanche Formation ◽  
Snow Samples

Abstract. Earth's snow cover is very dynamic on diurnal time scales. The changes to the snow structure during this metamorphism have wide ranging impacts such as on avalanche formation and on the capacity of surface snow to exchange trace gases with the atmosphere. Here, we investigate the influence of dry metamorphism, which involves fluxes of water vapor, on the chemical reactivity of bromide in the snow. For this, the heterogeneous reactive loss of ozone at a concentration of 5–6 x 1012 molecules cm-3 is investigated in artificial, shock-frozen snow samples doped with 6.2 μM sodium bromide and with varying metamorphism history. The oxidation of bromide in snow is one reaction initiating polar bromine releases and ozone depletions. We find that the heterogeneous reactivity of bromide is completely absent from the air-ice interface in snow after 12 days of temperature gradient metamorphism and suggest that burial of non-volatile bromide salts occurs when the snow matrix is restructuring during metamorphism. Impacts on polar atmospheric chemistry are discussed.

scholarly journals Stable-isotope time series and precipitation origin from firn-core and snow samples, Altai glaciers, Siberia

2005 ◽  
Vol 51 (175) ◽  
pp. 637-654 ◽  
Author(s):  
Vladimir B. Aizen ◽  
Elena Aizen ◽  
Koji Fujita ◽  
Stanislav A. Nikitin ◽  
Karl J. Kreutz ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Clustering Analysis ◽  
Meteoric Water ◽  
Drainage Basin ◽  
The Arctic ◽  
Deuterium Excess ◽  
Closed Drainage ◽  
Water Stable Isotope ◽  
Firn Core ◽  
Snow Samples

AbstractIn the summers of 2001 and 2002, glacio-climatological research was performed at 4110–4120 m a.s.l. on the Belukha snow/firn plateau, Siberian Altai. Hundreds of samples from snow pits and a 21 m snow/firn core were collected to establish the annual/seasonal/monthly depth–accumulation scale, based on stable-isotope records, stratigraphic analyses and meteorological and synoptic data. The fluctuations of water stable-isotope records show well-preserved seasonal variations. The δ18O and δD relationships in precipitation, snow pits and the snow/firn core have the same slope to the covariance as that of the global meteoric water line. The origins of precipitation nourishing the Belukha plateau were determined based on clustering analysis of δ18O and d-excess records and examination of synoptic atmospheric patterns. Calibration and validation of the developed clusters occurred at event and monthly timescales with about 15% uncertainty. Two distinct moisture sources were shown: oceanic sources with d-excess <12‰, and the Aral–Caspian closed drainage basin sources with d-excess >12‰. Two-thirds of the annual accumulation was from oceanic precipitation, of which more than half had isotopic ratios corresponding to moisture evaporated over the Atlantic Ocean. Precipitation from the Arctic/Pacific Ocean had the lowest deuterium excess, contributing one-tenth to annual accumulation.

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