Deuterium and oxygen-18 isotope composition of precipitation and atmospheric moisture

Araguás‐Araguás, Luis; Froêhlich, K.; Różański, Kazimierz

doi:10.1002/1099-1085(20000615)14:8<1341::aid-hyp983>3.0.co;2-z

Cited by 544 publications

(200 citation statements)

References 40 publications

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“…The isotope effect of vegetation has not been considered by most isotope-enabled GCMs perhaps because: (1) a general assumption that the isotopic composition of transpired water equals that of precipitation, (2) a lack of our prognostic ability to quantify the ratio of transpiration to evaporation, and (3) the scarcity of uninterrupted stable isotope ratio measurements in water vapor over actively transpiring vegetated landscapes. The d 2 H and d 18 O values in precipitation are measured routinely and archived by the International Atomic Energy Agency's Global Network for Isotopes in Precipitation (Rozanski et al 1993;Araguas-Araguas et al 2000). Only a handful of observations were made that reported both 2 H and 18 O isotope ratios in water vapor, including those measured over the sea surface (Craig and Gordon 1965;Gat et al 2003), in the upper troposphere (Webster and Heymsfield 2003;Worden et al 2007), in forests or woodlands (Moreira et al 1997;Yepez et al 2003), over rice crops (Brunel et al 1992) and in an urban area (Wen et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Deuterium excess reveals diurnal sources of water vapor in forest air

Lai

Ehleringer

2010

Oecologia

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An understanding of atmospheric water vapor content and its isotopic composition is important if we are to be able to model future water vapor dynamics and their potential feedback on future climate change. Here we present diurnal and vertical patterns of water isotope ratios in forest air (δ(2)H(v) and δ(18)O(v)) not observed previously. Water vapor observed at three heights over 3 consecutive days in a coniferous forest in the Pacific Northwest of the United States, shows a stratified nocturnal structure of δ(2)H(v) and δ(18)O(v), with the most positive values consistently observed above the canopy (60 m). Differences between 0.5 m and 60 m range between 2-6‰ for δ(18)O and 20-40‰ for δ(2)H at night. Using a box model, we simulated H(2)O isotope fluxes and showed that the low to high δ(2)H(v) and δ(18)O(v) profiles can be explained by the vapor flux associated with evaporation from the forest floor and canopy transpiration. We used d-excess as a diagnostic tracer to identify processes that contribute to the diurnal variation in atmospheric moisture. Values of d-excess derived from water vapor measurements showed a repeated diel pattern, with the lowest values occurring in the early morning and the highest values occurring at midday. The isotopic composition of rain water, collected during a light rain event in the first morning of our experiment, suggested that considerable below-cloud secondary evaporation occurred during the descent of raindrops. We conclude that atmospheric entrainment appears to drive the isotopic variation of water vapor in the early morning when the convective boundary layer rapidly develops, while evapotranspiration becomes more important in the mid-afternoon as a primary moisture source of water vapor in this forest. Our results demonstrate the interplay between the effects of vegetation and boundary layer mixing under the influence of rain evaporation, which has implications for larger-scale predictions of precipitation across the terrestrial landscape.

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Section: Introductionmentioning

confidence: 99%

Deuterium excess reveals diurnal sources of water vapor in forest air

Lai

Ehleringer

2010

Oecologia

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“…It is strongly related to the climatological parameters involved in the evaporation, transport, and condensation of the moisture forming precipitation (Dansgaard 1964;Gat 1996;Araguás-Araguás et al 2000). As a consequence, paleoclimatic conditions have been successfully retrieved at different time scales from the isotopic records in polar and mid-to low-latitude ice cores (Charles et al 1994;Yao et al 1997; Thompson et al 2002Thompson et al , 2009.…”

Section: Introductionmentioning

confidence: 99%

“…A linear relationship between d 18 O and dD in precipitation is observed on a global scale (Araguás-Araguás et al 2000), due to their parallel fractionation during water cycling. However, the kinetic non-equilibrium processes during water evaporation can influence the effective fractionation factors, resulting in an excess value in the relationship between d 18 O and dD, which has been defined by Dansgaard (1964) as deuterium excess (d = dD -8*d 18 O).…”

Section: Introductionmentioning

confidence: 99%

Deuterium excess record in a southern Tibetan ice core and its potential climatic implications

Zhao

Yao

et al. 2011

Clim Dyn

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A 55-m long ice core, drilled close to bedrock from Mt. Noijin Kangsang on the southern Tibetan Plateau in summer 2007, was annually dated covering the period of 1864-2006 AD. The stable isotope ratios (d 18 O and dD) of the ice core were measured and thereby the deuterium excess (d) was calculated by d = dD -8*d 18 O for the individual ice samples. Results show that the d values of the ice samples were predominantly controlled by the moisture sources. The significant increasing trend of annual mean d values along the ice core is mainly related to the rapid warming of the tropical Indian Ocean, although the tendency is subjected to the modulation by the westernderived moisture. The decreasing Indian monsoon precipitation on the southern Tibetan Plateau, physically linked with the increasing tropical Indian Ocean SST, reduced the share of monsoon precipitation in the annual total accumulation, making an additional contribution to the significant increase of annual mean d in the Noijin Kangsang ice core with high values during the past 143 years.

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“…Dry seasons could thus be reflected in an increased d 13 C of wood then synthesized from current assimilates. Wet seasons in the tropics are characterized by 18 O depleted precipitation water (Araguas-Araguas et al 2000), thus leading to a reduced d 18 O of source water. A parallel seasonality is thus expected for d 13 C and d 18 O.…”

Section: Introductionmentioning

confidence: 99%

Identification of anatomically non-distinct annual rings in tropical trees using stable isotopes

Pons

Helle

2010

Trees

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Annual rings are generally not anatomically distinct in trees growing in the humid tropics. The possibility to use radial variation in stable isotopes (d 18 O and d 13 C) for the identification of annual rings in these trees was investigated in two species growing in the tropical rainforest of Central Guyana, Carapa guianensis and Goupia glabra. The climate is characterised by an annual precipitation of 2,700 mm that is distributed over two rainy and two dry seasons. Cores were taken from trees of measured diameter increment rates. High-resolution tangential sections in radial direction were dissected from these cores and isotopic ratios were measured on whole wood. Variation in d 13 C was about 1% at an annual scale, whereas d 18 O showed two to four times larger annual excursions. The minima in d 18 O were selected as primary indicators of annual boundaries at the main wet season when also d 18 O of precipitation water has its minimum. The minima in d 13 C coincided often with these. The simultaneous occurrence is consistent with increased discrimination against 13 C at high water availability. They were used as secondary criteria. Annual rings could thus be identified with reasonable certainty in both species from radial variation in isotopic ratios as verified with measured diameter increment rates. The short sequence covered in the analysis did not show clear correlation with the available precipitation data for the area. The method supplemented with other dating methods may prove to be practically useful for identifying annual rings and applying classical dendrochronology when more cost effective automatic sampling devices become available.

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Deuterium and oxygen-18 isotope composition of precipitation and atmospheric moisture

Cited by 544 publications

References 40 publications

Deuterium excess reveals diurnal sources of water vapor in forest air

Deuterium excess reveals diurnal sources of water vapor in forest air

Deuterium excess record in a southern Tibetan ice core and its potential climatic implications

Identification of anatomically non-distinct annual rings in tropical trees using stable isotopes

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