Determination of the triple oxygen isotopic composition of tropospheric ozone in terminal positions using a multistep nitrite‐coated filter‐pack system

2021 ◽  
Author(s):  
Hao Xu ◽  
Urumu Tsunogai ◽  
Fumiko Nakagawa ◽  
Yijun Li ◽  
Masanori Ito ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Tropospheric Ozone ◽  
Oxygen Isotopic Composition ◽  
Filter Pack ◽  
Oxygen Isotopic

scholarly journals Quantifying atmospheric nitrate formation pathways based on a global model of the oxygen isotopic composition (Δ<sup>17</sup>O) of atmospheric nitrate

2009 ◽  
Vol 9 (14) ◽  
pp. 5043-5056 ◽  
Author(s):  
B. Alexander ◽  
M. G. Hastings ◽  
D. J. Allman ◽  
J. Dachs ◽  
J. A. Thornton ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Tropospheric Ozone ◽  
Oxygen Isotopic Composition ◽  
Global Model ◽  
Polar Regions ◽  
Relative Importance ◽  
Formation Pathway ◽  
Atmospheric Nitrate ◽  
Oxygen Isotopic ◽  
The Tropics

Abstract. The oxygen isotopic composition (Δ17O) of atmospheric nitrate is a function of the relative abundance of atmospheric oxidants (O3, ROx=OH+HO2+RO2) and the formation pathway of nitrate from its precursor NOx (=NO+NO2). Coupled observations and modeling of nitrate Δ17O can be used to quantify the relative importance of chemical formation pathways leading to nitrate formation and reduce uncertainties in the budget of reactive nitrogen chemistry in the atmosphere. We present the first global model of atmospheric nitrate Δ17O and compare with available observations. The largest uncertainty for calculations of nitrate Δ17O is the unconstrained variability in the Δ17O value of tropospheric ozone. The model shows the best agreement with a global compilation of observations when assuming a Δ17O value of tropospheric ozone equal to 35‰ and preferential oxidation of NOx by the terminal oxygen atoms of ozone. Calculated values of annual-mean nitrate Δ17O in the lowest model layer (0–200 m above the surface) vary from 7‰ in the tropics to 41‰ in the polar-regions. The global, annual-mean tropospheric inorganic nitrate burden is dominated by nitrate formation via NO2+OH (76%), followed by N2O5 hydrolysis (18%) and NO3+DMS/HC (4%). Calculated nitrate Δ17O is sensitive to the relative importance of each nitrate formation pathway, suggesting that observations of nitrate Δ17O can be used to quantify the importance of individual reactions (e.g. N2O5 hydrolysis) leading to nitrate formation if the Δ17O value of ozone is known.

Determination of the Total Oxygen Isotopic Composition of Nitrate and the Calibration of a Δ17Ο Nitrate Reference Material

2002 ◽  
Vol 74 (19) ◽  
pp. 4989-4993 ◽  
Author(s):  
Greg Michalski ◽  
Joel Savarino ◽  
J. K. Böhlke ◽  
Mark Thiemens
Keyword(s):  
Reference Material ◽  
Isotopic Composition ◽  
Oxygen Isotopic Composition ◽  
Total Oxygen ◽  
Oxygen Isotopic

Improved Method for the Determination of the Oxygen Isotopic Composition of Cellulose

1994 ◽  
Vol 66 (14) ◽  
pp. 2409-2411 ◽  
Author(s):  
Peter E. Sauer ◽  
Leonel d. S. L. O. Sternberg
Keyword(s):  
Isotopic Composition ◽  
Oxygen Isotopic Composition ◽  
Improved Method ◽  
Oxygen Isotopic

Changes of Ionic and Oxygen Isotopic Composition of the Snowpack at the Glacier Austre Okstindbreen, Norway, 1995

1998 ◽  
Vol 29 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Peter Raben ◽  
Wilfred H. Theakstone
Keyword(s):  
Isotopic Composition ◽  
Sea Level ◽  
Oxygen Isotopes ◽  
Oxygen Isotopic Composition ◽  
Isotopic Ratios ◽  
Vertical Variations ◽  
Oxygen Isotopic ◽  
The Difference ◽  
Liquid Precipitation ◽  
Different Altitudes

Marked vertical variations of ions and oxygen isotopes were present in the snowpack at the glacier Austre Okstindbreen during the pre-melting phase in 1995 at sites between 825 m and 1,470 m above sea level. As the first meltwater percolated from the top of the pack, ions were moved to a greater depth, but the isotopic composition remained relatively unchanged. Ions continued to move downwards through the pack during the melting phase, even when there was little surface melting and no addition of liquid precipitation. The at-a-depth correlation between ionic concentrations and isotopic ratios, strong in the pre-melting phase, weakened during melting. In August, concentrations of Na+ and Mg2+ ions in the residual pack were low and vertical variations were slight; 18O enrichment had occurred. The difference of the time at which melting of the snowpack starts at different altitudes influences the input of ions and isotopes to the underlying glacier.

scholarly journals δ2Hn-alkane and δ18Osugar biomarker proxies from leaves and topsoils of the Bale Mountains, Ethiopia, and implications for paleoclimate reconstructions

2021 ◽  
Author(s):  
Bruk Lemma ◽  
Lucas Bittner ◽  
Bruno Glaser ◽  
Seifu Kebede ◽  
Sileshi Nemomissa ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Leaf Growth ◽  
Thermal Conversion ◽  
Oxygen Isotopic Composition ◽  
Leaf Water ◽  
Isotope Ratio Mass Spectrometer ◽  
Oxygen Isotopic ◽  
Calibration Study ◽  
Microclimatic Conditions ◽  
Paleoclimate Reconstructions

AbstractThe hydrogen isotopic composition of leaf wax–derived n-alkane (δ2Hn-alkane) and oxygen isotopic composition of hemicellulose–derived sugar (δ18Osugar) biomarkers are valuable proxies for paleoclimate reconstructions. Here, we present a calibration study along the Bale Mountains in Ethiopia to evaluate how accurately and precisely the isotopic composition of precipitation is imprinted in these biomarkers. n-Alkanes and sugars were extracted from the leaf and topsoil samples and compound–specific δ2Hn-alkane and δ18Osugar values were measured using a gas chromatograph–thermal conversion–isotope ratio mass spectrometer (GC–TC–IRMS). The weighted mean δ2Hn-alkane and δ18Osugar values range from − 186 to − 89‰ and from + 27 to + 46‰, respectively. Degradation and root inputs did not appear to alter the isotopic composition of the biomarkers in the soil samples analyzed. Yet, the δ2Hn-alkane values show a statistically significant species dependence and δ18Osugar yielded the same species–dependent trends. The reconstructed leaf water of Erica arborea and Erica trimera is 2H– and 18O–enriched by + 55 ± 5 and + 9 ± 1‰, respectively, compared to precipitation. By contrast, Festuca abyssinica reveals the most negative δ2Hn-alkane and least positive δ18Osugar values. This can be attributed to “signal–dampening” caused by basal grass leaf growth. The intermediate values for Alchemilla haumannii and Helichrysum splendidum can be likely explained with plant physiological differences or microclimatic conditions affecting relative humidity (RH) and thus RH–dependent leaf water isotope enrichment. While the actual RH values range from 69 to 82% (x̄ = 80 ± 3.4%), the reconstructed RH values based on a recently suggested coupled δ2Hn-alkane –δ18Osugar (paleo–) hygrometer approach yielded a mean of 78 ± 21%. Our findings corroborate (i) that vegetation changes, particularly in terms of grass versus non–grassy vegetation, need to be considered in paleoclimate studies based on δ2Hn-alkane and δ18Osugar records and (ii) that the coupled δ2Hn-alkane –δ18Osugar (paleo–) hygrometer approach holds great potential for deriving additional paleoclimatic information compared to single isotope approaches.

Oxygen isotopic composition as an indicator of ruby and sapphire origin: A review of Russian occurrences

2015 ◽  
Vol 68 ◽  
pp. 164-170 ◽  
Author(s):  
S.V. Vysotskiy ◽  
V.P. Nechaev ◽  
A.Yu. Kissin ◽  
V.V. Yakovenko ◽  
A.V. Ignat'ev ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Oxygen Isotopic Composition ◽  
Oxygen Isotopic
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