Isotope ratios of precipitation and water vapor observed in Typhoon Shanshan

2008 ◽  
Vol 113 (D12) ◽  
Author(s):  
H. Fudeyasu ◽  
K. Ichiyanagi ◽  
A. Sugimoto ◽  
K. Yoshimura ◽  
A. Ueta ◽  
...  
Keyword(s):  
Water Vapor ◽  
Isotope Ratios

scholarly journals Craig-Gordon model validation using observed meteorological parameters and measured stable isotope ratios in water vapor over the Southern Ocean

2019 ◽  
Author(s):  
Shaakir Shabir Dar ◽  
Prosenjit Ghosh ◽  
Ankit Swaraj ◽  
Anil Kumar
Keyword(s):  
Water Vapor ◽  
Surface Water ◽  
Southern Ocean ◽  
Isotopic Composition ◽  
Isotope Ratios ◽  
Mixing Processes ◽  
Relative Contribution ◽  
Molecular Diffusivity ◽  
Air Interface ◽  
Evaporation Flux

Abstract. The stable isotopic composition of water vapor over the ocean is governed by the isotopic composition of surface water, ambient vapor isotopic composition, exchange and mixing processes at the water-air interface as well as the local meteorological conditions. In this study we present water vapor and surface water isotope ratios in samples collected across the latitudinal transect from Mauritius to Prydz Bay in the Antarctic coast. The samples were collected on-board the ocean research vessel SA Agulhas during the 9th (Jan-2017) and 10th (Dec-2017 to Jan-2018) Southern Ocean expeditions. The inter annual variability of the meteorological factors governing water vapor isotopic composition is explained. The parameters governing the isotopic composition of evaporation flux from the oceans can be considered separately or simultaneously in the Craig-Gordon (CG) models. The Traditional Craig-Gordon (TCG) (Craig and Gordon, 1965) and the Unified Craig-Gordon (UCG) (Gonfiantini et al., 2018) models were used to evaluate the isotopic composition of evaporation flux for the molecular diffusivity ratios suggested by Merlivat (1978) (MJ), Cappa et al. (2003) (CD) and Pfahl and Wernli (2009) (PW) and for different ocean surface conditions. We found that the UCG model with CD molecular diffusivity ratios where equal contribution from molecular and turbulent diffusion is the best match for our observations. By assigning the representative end member isotopic compositions and solving the two-component mixing model, a relative contribution from locally generated and advected moisture was calculated along the transect. Our results suggest varying contribution of advected westerly component with an increasing trend upto 65° S. Beyond 65° S, the proportion of Antarctic moisture was found to be increasing linearly towards the coast.

scholarly journals The influence of snow sublimation and meltwater evaporation on <i>δ</i>D of water vapor in the atmospheric boundary layer of central Europe

2017 ◽  
Vol 17 (2) ◽  
pp. 1207-1225 ◽  
Author(s):  
Emanuel Christner ◽  
Martin Kohler ◽  
Matthias Schneider
Keyword(s):  
Water Vapor ◽  
Central Europe ◽  
Isotope Fractionation ◽  
Experimental Studies ◽  
Isotope Ratios ◽  
Sensitivity Study ◽  
Stable Water Isotopes ◽  
Uncertainty Range ◽  
Moisture Sources ◽  
Isotope Concentration

Abstract. Post-depositional fractionation of stable water isotopes due to fractionating surface evaporation introduces uncertainty to various isotope applications such as the reconstruction of paleotemperatures, paleoaltimetry, and the investigation of groundwater formation. In this study, we investigate isotope fractionation at snow-covered moisture sources by combining 17 months of observations of isotope concentration ratios [HD16O] ∕ [H216O] in low-level water vapor in central Europe with a new Lagrangian isotope model. The isotope model is capable of reproducing variations of the observed isotope ratios with a correlation coefficient R of 0.82. Observations from 38 days were associated with cold snaps and moisture uptake in snow-covered regions. Deviations between modeled and measured isotope ratios during the cold snaps were related to differences in skin temperatures (Tskin). Analysis of Tskin provided by the Global Data Assimilation System (GDAS) of the NCEP implies the existence of two regimes of Tskin with different types of isotope fractionation during evaporation: a cold regime with Tskin < Tsubl,max = −7.7 °C, which is dominated by non-fractionating sublimation of snow, and a warmer regime with Tsubl,max < Tskin < 0 °C, which is dominated by fractionating evaporation of meltwater. Based on a sensitivity study, we assess an uncertainty range of the determined Tsubl,max of −11.9 to −2.9 °C. The existence of the two fractionation regimes has important implications for the interpretation of isotope records from snow-covered regions as well as for a more realistic modeling of isotope fractionation at snow-covered moisture sources. For these reasons, more detailed experimental studies at snow-covered sites are needed to better constrain the Tsubl,max and to further investigate isotope fractionation in the two regimes.

scholarly journals Water vapor and precipitation isotope ratios in Beijing, China

2010 ◽  
Vol 115 (D1) ◽  
Author(s):  
Xue-Fa Wen ◽  
Shi-Chun Zhang ◽  
Xiao-Min Sun ◽  
Gui-Rui Yu ◽  
Xuhui Lee
Keyword(s):  
Water Vapor ◽  
Isotope Ratios ◽  
Beijing China

Continuous measurement of water vapor D/H and 18O/16O isotope ratios in the atmosphere

2008 ◽  
Vol 349 (3-4) ◽  
pp. 489-500 ◽  
Author(s):  
Xue-Fa Wen ◽  
Xiao-Min Sun ◽  
Shi-Chun Zhang ◽  
Gui-Rui Yu ◽  
Steve D. Sargent ◽  
...  
Keyword(s):  
Water Vapor ◽  
Continuous Measurement ◽  
Isotope Ratios

scholarly journals Craig–Gordon model validation using stable isotope ratios in water vapor over the Southern Ocean

2020 ◽  
Vol 20 (19) ◽  
pp. 11435-11449
Author(s):  
Shaakir Shabir Dar ◽  
Prosenjit Ghosh ◽  
Ankit Swaraj ◽  
Anil Kumar
Keyword(s):  
Water Vapor ◽  
Surface Water ◽  
Southern Ocean ◽  
Isotopic Composition ◽  
Isotope Ratios ◽  
Mixing Processes ◽  
Vapor Flux ◽  
Relative Contribution ◽  
Molecular Diffusivity ◽  
Air Interface

Abstract. The stable oxygen and hydrogen isotopic composition of water vapor over a water body is governed by the isotopic composition of surface water and ambient vapor, exchange and mixing processes at the water–air interface, and the local meteorological conditions. These parameters form inputs to the Craig–Gordon models, used for predicting the isotopic composition of vapor produced from the surface water due to the evaporation process. In this study we present water vapor, surface water isotope ratios and meteorological parameters across latitudinal transects in the Southern Ocean (27.38–69.34 and 21.98–66.8∘ S) during two austral summers. The performance of Traditional Craig–Gordon (TCG) (Craig and Gordon, 1965) and the Unified Craig–Gordon (UCG) (Gonfiantini et al., 2018) models is evaluated to predict the isotopic composition of evaporated water vapor flux in the diverse oceanic settings. The models are run for the molecular diffusivity ratios suggested by Merlivat (1978), Cappa et al. (2003) and Pfahl and Wernli (2009), referred to as MJ, CD and PW, respectively, and different turbulent indices (x), i.e., fractional contribution of molecular vs. turbulent diffusion. It is found that the UCGx=0.8MJ, UCGx=0.6CD, TCGx=0.6MJ and TCGx=0.7CD models predicted the isotopic composition that best matches with the observations. The relative contribution from locally generated and advected moisture is calculated at the water vapor sampling points, along the latitudinal transects, assigning the representative end-member isotopic compositions, and by solving the two-component mixing model. The results suggest a varying contribution of the advected westerly component, with an increasing trend up to 65∘ S. Beyond 65∘ S, the proportion of Antarctic moisture was found to be prominent and increasing linearly towards the coast.

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