Variation in isotopic composition of precipitation with identification of vapor source using deuterium excess as tool

2022 ◽  
Author(s):  
Fariha Malik ◽  
Saira Butt ◽  
Nouman Mujahid
Keyword(s):  
Isotopic Composition ◽  
Deuterium Excess ◽  
Vapor Source

scholarly journals Annual variation in event-scale precipitation <i>δ</i><sup>2</sup>H at Barrow, AK, reflects vapor source region

2017 ◽  
Vol 17 (7) ◽  
pp. 4627-4639 ◽  
Author(s):  
Annie L. Putman ◽  
Xiahong Feng ◽  
Leslie J. Sonder ◽  
Eric S. Posmentier
Keyword(s):  
Source Region ◽  
Arctic Sea Ice ◽  
Dew Point ◽  
Precipitation Event ◽  
Boolean Variable ◽  
Deuterium Excess ◽  
Vapor Source ◽  
Source Regions ◽  
Circulation Cell ◽  
Transport Path

Abstract. In this study, precipitation isotopic variations at Barrow, AK, USA, are linked to conditions at the moisture source region, along the transport path, and at the precipitation site. Seventy precipitation events between January 2009 and March 2013 were analyzed for δ2H and deuterium excess. For each precipitation event, vapor source regions were identified with the hybrid single-particle Lagrangian integrated trajectory (HYSPLIT) air parcel tracking program in back-cast mode. The results show that the vapor source region migrated annually, with the most distal (proximal) and southerly (northerly) vapor source regions occurring during the winter (summer). This may be related to equatorial expansion and poleward contraction of the polar circulation cell and the extent of Arctic sea ice cover. Annual cycles of vapor source region latitude and δ2H in precipitation were in phase; depleted (enriched) δ2H values were associated with winter (summer) and distal (proximal) vapor source regions. Precipitation δ2H responded to variation in vapor source region as reflected by significant correlations between δ2H with the following three parameters: (1) total cooling between lifted condensation level (LCL) and precipitating cloud at Barrow, ΔTcool, (2) meteorological conditions at the evaporation site quantified by 2 m dew point, Td, and (3) whether the vapor transport path crossed the Brooks and/or Alaskan ranges, expressed as a Boolean variable, mtn. These three variables explained 54 % of the variance (p<0. 001) in precipitation δ2H with a sensitivity of −3.51 ± 0.55 ‰ °C−1 (p<0. 001) to ΔTcool, 3.23 ± 0.83 ‰ °C−1 (p<0. 001) to Td, and −32.11 ± 11.04 ‰ (p = 0. 0049) depletion when mtn is true. The magnitude of each effect on isotopic composition also varied with vapor source region proximity. For storms with proximal vapor source regions (where ΔTcool <7 °C), ΔTcool explained 3 % of the variance in δ2H, Td alone accounted for 43 %, while mtn explained 2 %. For storms with distal vapor sources (ΔTcool > 7°C), ΔTcool explained 22 %, Td explained only 1 %, and mtn explained 18 %. The deuterium excess annual cycle lagged by 2–3 months during the δ2H cycle, so the direct correlation between the two variables is weak. Vapor source region relative humidity with respect to the sea surface temperature, hss, explained 34 % of variance in deuterium excess, (−0.395 ± 0.067 ‰ %−1, p<0. 001). The patterns in our data suggest that on an annual scale, isotopic ratios of precipitation at Barrow may respond to changes in the southerly extent of the polar circulation cell, a relationship that may be applicable to interpretation of long-term climate change records like ice cores.

scholarly journals The Isotopic Composition of Present-Day Antarctic Snow in a Lagrangian Atmospheric Simulation*

2007 ◽  
Vol 20 (4) ◽  
pp. 739-756 ◽  
Author(s):  
M. M. Helsen ◽  
R. S. W. Van de Wal ◽  
M. R. Van den Broeke
Keyword(s):  
Isotopic Composition ◽  
General Circulation ◽  
Isotopic Fractionation ◽  
General Circulation Models ◽  
Deuterium Excess ◽  
West Antarctica ◽  
Temperature Relation ◽  
Weather Forecasts ◽  
Spatial Differences ◽  
Antarctic Snow

Abstract The isotopic composition of present-day Antarctic snow is simulated for the period September 1980–August 2002 using a Rayleigh-type isotope distillation model in combination with backward trajectory calculations with 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) data as meteorological input. Observed spatial isotopic gradients are correctly reproduced, especially in West Antarctica and in the coastal areas. However, isotopic depletion of snow on the East Antarctic plateau is underestimated, a problem that is also observed in general circulation models equipped with isotope tracers. The spatial isotope–temperature relation varies strongly, which indicates that this widely used relation is not applicable to all sites and temporal scales. Spatial differences in the seasonal amplitude are identified, with maximum values in the Antarctic interior and hardly any seasonal isotope signature in Marie Byrd Land, West Antarctica. The modeled signature of deuterium excess remains largely preserved during the last phase of transport, though the simulated relation of deuterium excess with δ18O suggests that parameterizations of kinetic isotopic fractionation can be improved.

A Stochastic Model for Diagnosing Subtropical Humidity Dynamics with Stable Isotopologues of Water Vapor

2016 ◽  
Vol 73 (4) ◽  
pp. 1741-1753 ◽  
Author(s):  
Joseph Galewsky ◽  
David Rabanus
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Stochastic Model ◽  
Isotopic Composition ◽  
Model Parameters ◽  
Mixing Ratio ◽  
Deuterium Excess ◽  
Freeze Dried ◽  
Saturation Distribution ◽  
Cold Point

Abstract The humidity of the free troposphere can be modeled, to first order, in terms of cold-point dehydration, followed by moistening via mixing with boundary layer air. The relative balance between these processes is of prime interest for understanding interannual variability of humidity and for understanding the water vapor feedback. Measurements of water vapor isotopic composition can provide quantitative constraints on these processes. The authors developed a stochastic model that parameterizes water vapor isotopic composition in terms of these processes and fit the model parameters to data from the Chajnantor Plateau, Chile (23°S). For August–November 2012, the average mixing ratio was 1680 ppmv, with mean water vapor δD of −234‰ and mean deuterium excess of 21‰. The data were best fit by an asymmetric last-saturation distribution with mean last-saturation mixing ratio rs of 391 (+45, −75) ppmv, a median rs of 368 (+45, −75) ppmv, and a mean mixing fraction between the freeze-dried air and moist boundary layer air of . Measurements from August to November 2014 had an average mixing ratio of 2210 ppmv, an average δD of −220‰, and an average deuterium excess of 14‰. The last-saturation distribution for this period was less skewed than for 2012, with an average rs of 520 (+42, −75) ppmv and a median rs of 507 (+25, −75) ppmv. The mean mixing fraction for 2014 was . The results show that the moistening in 2014, relative to 2012, requires increases in both the last-saturation mixing ratio and the postcondensation moistening and illustrate the utility of isotopic measurements for constraining the processes governing subtropical humidity.

Analysis of stable isotopic composition and vapor source of precipitation at the Changwu Loess Tableland

2016 ◽  
Vol 36 (1) ◽  
Author(s):  
陈曦 CHEN Xi ◽  
李志 LI Zhi ◽  
程立平 CHENG Liping ◽  
刘文兆 LIU Wenzhao ◽  
王锐 WANG Rui
Keyword(s):  
Isotopic Composition ◽  
Vapor Source ◽  
Stable Isotopic Composition ◽  
Stable Isotopic

scholarly journals Monitoring of stable isotopes (δ2H, δ18O) in precipitations of Moscow city (Russia): comparison for 2005–2014 and 1970–1979 periods

2021 ◽  
Vol 66 (4) ◽  
Author(s):  
Nikolay N. Zykin ◽  
◽  
Igor V. Tokarev ◽  
Natalia A. Vinograd ◽  
◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Atmospheric Precipitation ◽  
Deuterium Excess ◽  
Monthly Average ◽  
The Past ◽  
Moscow City ◽  
Meteorological Observations ◽  
Accumulation Method ◽  
Observation Period ◽  
Equilibrium Fractionation

The isotopic composition of oxygen (δ18O) and hydrogen (δ2H) of atmospheric precipitation in Moscow in 2005–2014 was studied by sampling single precipitations (a total of 842 measurements after rejection of unreliable samples). A comparison is made with similar studies carried out by VSEGINGEO and IVP RAS for the IAEA-WMO GNIP network in 1969–1979, when monthly average samples were taken by the accumulation method (61 pair determinations of deuterium and oxygen-18, mainly in 1975–1979). The 2005–2015 series is reduced to a similar form for the 1969–1979 series, recalculated through the data on the volume of precipitation at the nearest meteorological station. It was found that in the last decade there has been a significant change in the equation of the local line of meteoric waters, which for the first period had the form δ2H = 6.09×δ18O – 23.0 ‰ (R2 = 0.87), and is currently described by the relation δ2H = 6.93×δ18O – 11.3 ‰ (R2 = 0.944). There is also a decrease in depletion of the average values of δ2H and δ18O, compared with the first observation period, which apparently reflects the course of climatic changes. At the same time, within each of the periods, a negative (albeit relatively small) slope of the line of approximation of chronological data is noted. Deuterium excess naturally changes seasonally, taking negative values in summer, primarily due to non-equilibrium fractionation during evaporation. In 2005–2014, the temperature dependence of the isotopic composition of precipitation changed significantly in comparison with 1969–1979, which makes it impossible to reconstruct the composition of precipitation in the past from meteorological observations.

scholarly journals Three-year monitoring of stable isotopes of precipitation at Concordia Station, East Antarctica

2016 ◽  
Author(s):  
Barbara Stenni ◽  
Claudio Scarchilli ◽  
Valerie Masson-Delmotte ◽  
Elisabeth Schlosser ◽  
Virginia Ciardini ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Isotopic Composition ◽  
Air Temperature ◽  
General Circulation ◽  
Daily Precipitation ◽  
Circulation Model ◽  
Ice Cores ◽  
Condensation Temperature ◽  
Deuterium Excess ◽  
Medium Range Weather Forecast

Abstract. Past temperature reconstructions from Antarctic ice cores require a good quantification and understanding of the relationship between snow isotopic composition and 2&amp;thninsp;m air or inversion (condensation) temperature. Here, we focus on the French-Italian Concordia Station, central East Antarctic plateau, where the European Project for Ice Coring in Antarctica (EPICA) Dome C ice cores were drilled. We provide a multi-year record of daily precipitation types identified from crystal morphologies, daily precipitation amounts, and isotopic composition. Our sampling period (2008–2010) encompasses a warmer year (2009, +1.6 °C with respect to 2&amp;thninsp;m air temperature period average), with larger total precipitation and snowfall amounts (14 %, 76 % above average, respectively), and a colder and drier year (2010, −1.4 °C, 4 % below average, respectively) with larger diamond dust amounts (49 % above average). Relationships between local meteorological data and precipitation isotopic composition are investigated at daily, monthly and inter-annual scale, and for the different types of precipitation. Water stable isotopes are more closely related to 2 m air temperature than to inversion temperature at all time scales (e.g. R2 = 0.63 and 0.44, respectively for daily values). The slope of the temporal relationship between daily d18O and 2 m air temperature is approximately two times smaller (0.49 ‰/°C) than the average Antarctic spatial (0.8 ‰/°C) relationship initially used for the interpretation of EPICA Dome C records. In accordance to results from precipitation monitoring at Vostok and Dome F, deuterium excess is anti-correlated with δ18O at daily and monthly scales, reaching maximum values in winter. Hoar frost precipitation samples have a specific fingerprint with more depleted d18O (about 5 ‰ below average) and higher deuterium excess (about 8 ‰ above average) values than other precipitation types. These datasets provide a basis for comparison with shallow ice core records, to investigate post-deposition effects. A preliminary comparison between observations and precipitation from the European Centre for Medium-Range Weather Forecast (ECMWF) re-analysis and the simulated water stable isotopes from the Laboratoire de Météorologie Dynamique Zoom atmospheric general circulation model (LMDZiso), shows that models do correctly capture the amount of precipitation as well as more than 50 % of the variance of the observed δ18O, driven by large scale weather patterns. Despite a warm bias and an underestimation of the variance in water stable isotopes, LMDZiso correctly captures these relationships between δ18O, 2 m air temperature and deuterium excess. Our dataset is therefore available for further in depth model evaluation at the synoptic scale.

scholarly journals Deuterium excess in atmospheric water vapor of a Mediterranean coastal wetland: regional versus local signatures

2015 ◽  
Vol 15 (2) ◽  
pp. 1703-1746 ◽  
Author(s):  
H. Delattre ◽  
C. Vallet-Coulomb ◽  
C. Sonzogni
Keyword(s):  
Water Vapor ◽  
Coastal Wetland ◽  
Deuterium Excess ◽  
Atmospheric Water ◽  
Time Step ◽  
Vapor Source ◽  
Air Mass ◽  
Air Masses ◽  
Clear Separation ◽  
Hourly Data

Abstract. Stable isotopes of the water vapor represent a powerful tool for tracing atmospheric vapor origin and mixing processes. Laser spectrometry recently allowed high time resolution measurements, but despite an increasing number of experimental studies, there is still a need for a better understanding of the main drivers of isotopic signal variability at different time scales. We present results of in situ measurements of δ18O and δD during 36 consecutive days in summer 2011 in atmospheric vapor of a Mediterranean coastal wetland exposed to high evapotranspiration (Camargue, Rhône River delta, France). A calibration protocol was tested and instrument stability was analysed over the period. The mean composition of atmospheric vapor during the campaign is δ18O = −14.66‰ and δD = −95.4‰, with δv data plotting clearly above the local meteoric water line, and an average deuterium excess (dv) of 21.9‰. At daily time step, we show a clear separation of isotopic characteristics with respect to the air mass back trajectories, with the Northern air masses providing depleted compositions (δ18O = −15.83‰, δD = −103.5‰) compared to Mediterranean air masses (δ18O = −13.13‰, δD = −86.5‰). There is also a clear separation between dv corresponding to these different air mass origins, but not in the same direction as was previously evidenced from regional rainfall data, with higher dv found for Northern air masses (23.2‰) than for Mediterranean air masses (18.6‰). Based on twenty-four average hourly data, we propose a depiction of typical daily evolution of water vapor isotopic composition. High diurnal variations in dv is attributed to a dominant control of evapotranspiration, over entrainment of free atmosphere. Daily cycles in dv are more pronounced for Mediterranean than for North Atlantic air mass origin and are discussed in terms of local evapotranspiration versus regional signatures. We calculate the composition of the vapor source that produces the day-time increase in dv for the different air mass origins, and propose an atmospheric water and isotopic mass balance.

scholarly journals Coupling δ<sup>2</sup>H and δ<sup>18</sup>O biomarker results yields information on relative humidity and isotopic composition of precipitation – a climate transect validation study

2015 ◽  
Vol 12 (12) ◽  
pp. 3913-3924 ◽  
Author(s):  
M. Tuthorn ◽  
R. Zech ◽  
M. Ruppenthal ◽  
Y. Oelmann ◽  
A. Kahmen ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Isotopic Composition ◽  
Validation Study ◽  
Leaf Water ◽  
Deuterium Excess ◽  
Air Humidity ◽  
Leaf Wax ◽  
Relative Air Humidity ◽  
Paleoclimate Reconstructions ◽  
Hydrogen Isotopic Composition

Abstract. The hydrogen isotopic composition (δ2H) of leaf waxes, especially of n-alkanes (δ2Hn-alkanes), is increasingly used for paleohydrological and paleoclimate reconstructions. However, it is challenging to disentangle past changes in the isotopic composition of precipitation and changes in evapotranspirative enrichment of leaf water, which are both recorded in leaf wax δ2H values. In order to overcome this limitation, Zech M. et al. (2013) proposed a coupled δ2Hn-alkanes–δ18Osugar biomarker approach. This coupled approach allows for calculating (i) biomarker-based "reconstructed" δ2Hδ18O values of leaf water (δ2Hδ18Oleaf water), (ii) biomarker-based reconstructed deuterium excess (d-excess) of leaf water, which mainly reflects evapotranspirative enrichment and which can be used to reconstruct relative air humidity (RH) and (iii) biomarker-based reconstructed δ2Hδ18Oprecipitation values. Here we present a climate transect validation study by coupling new results from δ2H analyses of n-alkanes and fatty acids in topsoils along a climate transect in Argentina with previously measured δ18O results obtained for plant-derived sugars. Accordingly, both the reconstructed RH and δ2Hδ18Oprecipitation values correlate highly significantly with actual RH and δ2Hδ18Oprecipitation values. We conclude that compared to single δ2Hn-alkane or δ18Osugar records, the proposed coupled δ2Hn-alkane–δ18Osugar biomarker approach will allow more robust δ2Hδ18Oprecipitation reconstructions in future paleoclimate research. Additionally, the proposed coupled δ2Hn-alkane–δ18Osugar biomarker approach allows for the establishment of a "paleohygrometer", more specifically, the reconstruction of mean summer daytime RH changes/history.

Isotopic Fractionation in Wintertime Orographic Clouds

2016 ◽  
Vol 33 (12) ◽  
pp. 2663-2678 ◽  
Author(s):  
Douglas Lowenthal ◽  
A. Gannet Hallar ◽  
Ian McCubbin ◽  
Robert David ◽  
Randolph Borys ◽  
...  
Keyword(s):  
Water Vapor ◽  
Isotopic Composition ◽  
Mesoscale Model ◽  
Isotopic Fractionation ◽  
Early Morning ◽  
Cloud Water ◽  
Mixed Phase ◽  
Vapor Source ◽  
Vapor Cloud ◽  
Orographic Clouds

AbstractThe Isotopic Fractionation in Snow (IFRACS) study was conducted at Storm Peak Laboratory (SPL) in northwestern Colorado during the winter of 2014 to elucidate snow growth processes in mixed-phase clouds. The isotopic composition (δ18O and δD) of water vapor, cloud water, and snow in mixed-phase orographic clouds were measured simultaneously for the first time. The depletion of heavy isotopes [18O and deuterium (D)] was greatest for vapor, followed by snow, then cloud. The vapor, cloud, and snow compositions were highly correlated, suggesting similar cloud processes throughout the experiment. The isotopic composition of the water vapor was directly related to its concentration. Isotopic fractionation during condensation of vapor to cloud drops was accurately reproduced assuming equilibrium fractionation. This was not the case for snow, which grows by riming and vapor deposition. This implies stratification of vapor with altitude. The relationship between temperature at SPL and δ18O was used to show that the snow gained most of its mass within 922 m above SPL. Relatively invariant deuterium excess (d) in vapor, cloud water, and snow from day to day suggests a constant vapor source and Rayleigh fractionation during transport. The diurnal variation of vapor d reflected the differences between surface and free-tropospheric air during the afternoon and early morning hours, respectively. These observations will be used to validate simulations of snow growth using an isotope-enabled mesoscale model with explicit microphysics.

scholarly journals Glacial–interglacial changes in H<sub>2</sub><sup>18</sup>O, HDO and deuterium excess – results from the fully coupled ECHAM5/MPI-OM Earth system model

2016 ◽  
Vol 9 (2) ◽  
pp. 647-670 ◽  
Author(s):  
M. Werner ◽  
B. Haese ◽  
X. Xu ◽  
X. Zhang ◽  
M. Butzin ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Last Glacial Maximum ◽  
Ice Cores ◽  
Glacial Maximum ◽  
The Arctic ◽  
Spatial Gradient ◽  
Deuterium Excess ◽  
Last Glacial ◽  
Simulation Results ◽  
Fully Coupled

Abstract. In this study we present the first results of a new isotope-enabled general circulation model set-up. The model consists of the fully coupled ECHAM5/MPI-OM atmosphere–ocean model, enhanced by the JSBACH interactive land surface scheme and an explicit hydrological discharge scheme to close the global water budget. Stable water isotopes H218O and HDO have been incorporated into all relevant model components. Results of two equilibrium simulations under pre-industrial and Last Glacial Maximum conditions are analysed and compared to observational data and paleoclimate records for evaluating the model's performance in simulating spatial and temporal variations in the isotopic composition of the Earth's water cycle. For the pre-industrial climate, many aspects of the simulation results of meteoric waters are in good to very good agreement with both observations and earlier atmosphere-only simulations. The model is capable of adequately simulating the large spread in the isotopic composition of precipitation between low and high latitudes. A comparison to available ocean data also shows a good model–data agreement; however, a strong bias of overly depleted ocean surface waters is detected for the Arctic region. Simulation results under Last Glacial Maximum boundary conditions also fit to the wealth of available isotope records from polar ice cores, speleothems, as well as marine calcite data. Data–model evaluation of the isotopic composition in precipitation reveals a good match of the model results and indicates that the temporal glacial–interglacial isotope–temperature relation was substantially lower than the present spatial gradient for most mid- to high-latitudinal regions. As compared to older atmosphere-only simulations, a remarkable improvement is achieved for the modelling of the deuterium excess signal in Antarctic ice cores. Our simulation results indicate that cool sub-tropical and mid-latitudinal sea surface temperatures are key for this progress. A recently discussed revised interpretation of the deuterium excess record of Antarctic ice cores in terms of marine relative humidity changes on glacial–interglacial timescales is not supported by our model results.

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