Isotopic Equilibrium Between Precipitation and Water Vapor in Northern Patagonia and Its Consequences on δ<sup>18</sup>O<sub>cellulose</sub> Estimate

Penchenat, Tiphaine; Vimeux, Françoise; Daux, Valérie; Cattani, O.; Viale, Maximiliano; Villalba, Ricardo; Srur, Ana Marina; Outrequin, Clément

doi:10.1029/2019jg005418

Cited by 12 publications

(14 citation statements)

References 76 publications

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“…Isotopic equilibrium between the atmospheric water vapor and the liquid water phases is assumed in this article despite the recent isotopic disequilibrium claims (Mercer et al, 2020, andPenchenat et al, 2020). The authors advocating disequilibrium use monthly isotopic ratios at high altitude.…”

Section: Methods and Theoretical Backgroundmentioning

confidence: 99%

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On the Quantitative Tripartite Allocation of Atmospheric Vapor, Oqtav, by Oxygen 18

Hussein

Zouari²,

Anter

et al. 2020

Preprint

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The quantitative distribution of atmospheric vapor mixture, AVM, into three distinguished vapor end-members is lacking in the literature. This work fills such a gap. The isotope ratio, d18OL, of rainwater in Winter, and artificial condensates in Summer, gave the 18OV contents of local AVMs at temperature-dependent equilibrium, downtown Cairo city, Nile Delta apex. We used our models, SIMAM, CLAW, and SIGNALS to process the d18OV and the commensurate specific humidity, S, values in several AVM data sets for determining the percent and mass contributions of three moisture origins and their temporal waveforms. The proportions and masses revealed Marine vapor dominance, followed by evapotranspiration. By far, the free Troposphere source showed a slight input. The quota of each constituent manifests a delayed waveform vs. AVM d18O influx, which shows a diurnal peak and a nocturnal tunnel. The moderate ET percent inputs in Winter, and by daytime, impose significant AVM 18O enrichment. In contrast, the high Maritime vapor inputs in Summer, and by night, stand behind the depleted AVM 18O content. The relationships between the mass input of each source and the AVM isotope ratio show significant dispersion for the negative trend of the diurnal-nocturnal Marine vapor in the two seasons. Such a high scattering is due to the mingling of northern wind-gust diurnal convection (marked by low Marine vapor input) and northern steady nocturnal advection (characterized by high Marine vapor input). Marine vapor waveform has a 12-hour time-lag by the intertwining of turbulent diurnal transmission, and steady nocturnal transport, through the long trajectory (180 km) from the Mediterranean coast to Cairo. In contrast, the relationships between ET mass input and AVM isotope ratio, on the one hand, and between the Troposphere vapor mass input and AVM isotope ratio, on the other hand, manifest low-dispersion positive and negative regressions, respectively. Such a low dispersion is due to the short transport pathway, the narrow range of the biological input (that increases only by daytime), and sharp Troposphere downdraft (moving northward in Winter but southward in Summer). Also, the ET waveform has a Zero-hour time-lag, like that of the Tropospheric vapor. Albeit the low S value of the Troposphere vapor pole, its impact on the AVM isotopic depletion is significant due to its extremely shallow 18O content. The increase of the Tropospheric input at low AVM S values is related to regional drought, as expected. The high S values, of Marine and biotic origins, usually go with temperature apogees, especially in Summertime, as anticipated. The used models help in improving the time-series simulation of evaporation runs, since using seasonal d18OV and S markers is better than using a snapshot. The ternary-vapor-source allocation procedure is a breakthrough in isotope hydrology. This thoroughly useful procedure will prove its ultimate benefits when the users get CRDS laser-controlled devices for the continuous measurements of the isotopic ratios in the local AVMs.

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Section: Methods and Theoretical Backgroundmentioning

confidence: 99%

“…However, we keep the equilibrium assumption as it will not perturb the used model. Moreover, monthly precipitation sampling stands behind the claims against equilibrium (Mercer et al, 2020;and Penchenat et al, 2020). The hourly collection of the arti cial condensates in Summer, however, supplies successful waveforms.…”

Section: Methods and Theoretical Backgroundmentioning

confidence: 99%

On the Quantitative Tripartite Allocation of Atmospheric Vapor, Oqtav, by Oxygen 18

Hussein

Zouari²,

Anter

et al. 2020

Preprint

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“…Today, CRDS techniques have been shown to be useful for measuring δ v at continuously high‐resolution and thus, enabling real‐time analysis of δ v (Aemisegger et al, 2012; Tremoy et al, 2011; Wei et al, 2015) which can give advanced insights than precipitation alone (Lee et al, 2006). For example, the technique has been successfully deployed for monitoring sub‐tropical sub‐cloud raindrop evaporation (Li et al, 2020); for testing vapour equilibrium assumption for δ 18 O cellulose estimates (Penchenat et al, 2020); for investigating partitioning of evapotranspiration over a rice paddy field (Wei et al, 2015); diurnal and intra‐seasonal variations in evaporative signals at different heights above the Greenland ice sheet (Steen‐Larsen et al, 2013); and to characterize variation in δ v and their controlling factors during extreme precipitation events (Xu et al, 2022). To date, however, to our knowledge hardly any in situ studies have assessed δ v dynamics in the atmospheric boundary of urban green spaces in Central Europe.…”

Section: Introductionmentioning

confidence: 99%

“…Despite standard model assumptions of an equilibrium between δ v and precipitation, δ v can be out of equilibrium with local water sources (Fiorella et al, 2019) and can show gradual depletion with altitude (Horita et al, 2008). High‐resolution in situ monitoring of δ v allows testing of such equilibrium assumptions, but so far, very few studies have tested this with in situ ambient data (Mercer et al, 2020; Penchenat et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

High‐resolution in situ stable isotope measurements reveal contrasting atmospheric vapour dynamics above different urban vegetation

Ring,

Tetzlaff,

Dubbert

et al. 2023

Hydrological Processes

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We monitored stable water isotopes in liquid precipitation and atmospheric water vapour (δv) using in situ cavity ring‐down spectroscopy (CRDS) over a 2 month period in an urban green space area in Berlin, Germany. Our aim was to better understand the origins of atmospheric moisture and its link to water partitioning under contrasting urban vegetation. δv was monitored at multiple heights (0.15, 2 and 10 m) in grassland and forest plots. The isotopic composition of δv above both land uses was highly dynamic and positively correlated with that of rainfall indicating the changing sources of atmospheric moisture. Further, the isotopic composition of δv was similar across most heights of the 10 m profiles and between the two plots indicating high aerodynamic mixing. Only at the surface at ~0.15 m height above the grassland δv showed significant differences, with more enrichment in heavy isotopes indicative of evaporative fractionation especially after rainfall events. Further, disequilibrium between δv and precipitation composition was evident during and right after rainfall events with more positive values (i.e., values of vapour higher than precipitation) in summer and negative values in winter, which probably results from higher evapotranspiration and more convective precipitation events in summer. Our work showed that it is technically feasible to produce continuous, longer‐term data on δv isotope composition in urban areas from in situ monitoring using CRDS, providing new insights into water cycling and partitioning across the critical zone of an urban green space in Central Europe. Such data have the potential to better constrain the isotopic interface between the atmosphere and the land surface and to thus, improve ecohydrological models that can resolve evapotranspiration fluxes.

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“…If there is no surface effect as a result of clay or OM, the δ 18 O and δ 2 H content in soil water and the unconfined labelling water should be identical after reaching equilibrium (Penchenat et al, 2020;Wu et al, 2019) and vice versa. These two pools may complicate the positional relationship between SWL and LMWL and thus, affect estimations of the hydrological processes in topsoil.…”

Section: Introductionmentioning

confidence: 99%

Isotopic fractionation induced by a surface effect influences the estimation of the hydrological process of topsoil

Guo

Qin

et al. 2021

Hydrological Processes

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Isotopic heterogeneity in soil water has hindered the application of isotope compositions (δ 18 O and δ 2 H) in soil water dynamics. This heterogeneity has been suggested to be caused by soil properties such as organic matter (OM) and clay content. However, this is yet to be verified in field soil. We sampled the organic layer (O-horizon soil) with highly decomposed organic material and the A-horizon soil in western Sichuan, China, and equilibrated these samples with vapour created by unconfined labelling water. The relationship between soil properties and isotopic fractionation (ε T/U) between unconfined water and the total soil water was used to determine the lineconditioned excess (lc-excess) and source rain of A-horizon field soil by removing the influence of confined water. Equilibration experiments demonstrated a significant isotopic difference between the ε T/U levels in the A-horizon and O-horizon soils, indicating that OM plays an important role in isotopic fractionation. In field samples, the lc-excess of the unconfined A-horizon water was, on an average, 2.5‰ higher than that of bulk soil water. The average offsets between the annual rain and the estimated source rain of soil water decreased by 5.0 and 0.5‰ for hydrogen and oxygen after removing the influence of confined water. Isotopic heterogeneity should not be ignored while examining the evaporation of soil water, soil source rain, and hence the recent 'two water worlds' hypothesis, which is especially true for cases in which the soils contain high levels of OM.

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Isotopic Equilibrium Between Precipitation and Water Vapor in Northern Patagonia and Its Consequences on δ¹⁸O_cellulose Estimate

Cited by 12 publications

References 76 publications

On the Quantitative Tripartite Allocation of Atmospheric Vapor, Oqtav, by Oxygen 18

On the Quantitative Tripartite Allocation of Atmospheric Vapor, Oqtav, by Oxygen 18

High‐resolution in situ stable isotope measurements reveal contrasting atmospheric vapour dynamics above different urban vegetation

Isotopic fractionation induced by a surface effect influences the estimation of the hydrological process of topsoil

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Isotopic Equilibrium Between Precipitation and Water Vapor in Northern Patagonia and Its Consequences on δ18Ocellulose Estimate

Cited by 12 publications

References 76 publications

On the Quantitative Tripartite Allocation of Atmospheric Vapor, Oqtav, by Oxygen 18

On the Quantitative Tripartite Allocation of Atmospheric Vapor, Oqtav, by Oxygen 18

High‐resolution in situ stable isotope measurements reveal contrasting atmospheric vapour dynamics above different urban vegetation

Isotopic fractionation induced by a surface effect influences the estimation of the hydrological process of topsoil

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Product

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About

Isotopic Equilibrium Between Precipitation and Water Vapor in Northern Patagonia and Its Consequences on δ¹⁸O_cellulose Estimate