Craig–Gordon model validation using stable isotope ratios in water vapor over the Southern Ocean
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 Crai...
| Published in: | Atmospheric Chemistry and Physics |
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| Main Authors: | , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Copernicus Publications
2020
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| Subjects: | |
| Online Access: | https://doi.org/10.5194/acp-20-11435-2020 https://doaj.org/article/cb78f819e188455585f00a35efb136f0 |
| Summary: | 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 <math xmlns="http://www.w3.org/1998/Math/MathML" id="M3" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi mathvariant="normal">UCG</mi><mrow><mi>x</mi><mo>=</mo><mn mathvariant="normal">0.8</mn></mrow><mi mathvariant="normal">MJ</mi></msubsup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="48pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="7a72526eb9d05f6bb93fd3c13dc9f8ae"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-20-11435-2020-ie00001.svg" width="48pt" height="17pt" src="acp-20-11435-2020-ie00001.png"/></svg:svg> , <math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" ... |
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