Intra-Event Isotopic Changes in Water Vapor and Precipitation in South China

Li, Xingxian; Tang, Changyuan; Cui, Jingsi

doi:10.3390/w13070940

Cited by 8 publications

(4 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, in this study Δ d ‐excess TF–RF and Δ d ‐excess SF–RF increased progressively towards the end of the events, whereas Δ d ‐excess SF–TF decreased slightly. As mentioned above, this is because the sub‐cloud evaporation effect and a typical decrease in precipitation amount and raindrop size at the end of the rainfall event lead to the depletion of heavy isotopes in precipitation and lower d‐excess (e.g., Li et al, 2021). However, the canopy selection effect may explain the higher Δ d ‐excess TF–RF and Δ d ‐excess SF–RF at the end of the events.…”

Section: Discussionmentioning

confidence: 99%

High‐resolution temporal dynamics of intra‐storm isotopic composition of stemflow and throughfall in a Mediterranean Scots pine forest

Pinos

Llorens

Latron

2022

Hydrological Processes

View full text Add to dashboard Cite

Vegetation plays a significant role in the isotopic fractionation of rainwater during rainfall partitioning through the canopy into throughfall and stemflow. Most studies focus on the isotopic composition of throughfall, whereas that of stemflow has been studied much less frequently. Moreover, only three studies to date have investigated stemflow isotopic composition at the intra‐storm scale. Therefore, knowledge of the isotopic shift between rainfall and throughfall/stemflow at fine resolutions is sorely needed in order to better understand water input to forest soils. In this study, intra‐event rainfall, throughfall and stemflow in a Scots pine forest under Mediterranean conditions were monitored (5‐min time step) over a 20‐month period (May 2018 to December 2019) and water samples of each component were collected sequentially by means of automatic samplers for isotopic analysis (18O and 2H). Results obtained for 21 rainfall events show that throughfall was usually more enriched than rainfall and stemflow was more enriched than throughfall. Isotopic differences between rainfall and throughfall/stemflow indicated that throughfall was more depleted during the higher air temperature season whereas stemflow was more enriched. The isotopic shift did not show any direct relationship with either meteorological variables or the amount effect. At the intra‐storm scale, stemflow was more enriched than rainfall and throughfall at the start of the rainfall event and tended to decrease towards the end. Our results suggest that evaporation led to stemflow enrichment due to stemflow residing longer on the vegetative surfaces than throughfall. However, most fractionation factors can occur during the same event. Our study will improve understanding of the physical processes that control stemflow isotopic composition in coniferous trees before reaching the ground, as a step towards improving isotope‐based models for forest‐water interactions.

show abstract

Section: Discussionmentioning

confidence: 99%

High‐resolution temporal dynamics of intra‐storm isotopic composition of stemflow and throughfall in a Mediterranean Scots pine forest

Pinos

Llorens

Latron

2022

Hydrological Processes

View full text Add to dashboard Cite

show abstract

“…Indeed, in many cases such as stratiform rain systems, the S75 model outputs may not differ significantly from closed model outputs due to small differences between the isotope composition of the droplet and the atmosphere. On the other hand, smaller droplet sizes from stratiform rain may increase the importance of these effects (Li et al, 2021; Bolin, 1958). In other cases, such as convective thunderstorm systems where droplets form under cold conditions high in the troposphere, closed system models may function better in predicting isotope evolution of droplets because the droplet‐atmosphere isotope composition differences can be quite high (Bony et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

“…Several studies also use S75 to better understand precipitation processes at a local level. Using this model in a study in South China, Li et al (2021) suggest that isotope exchange has a stronger signature on precipitation when raindrop radii are smaller, and that isotope exchange with surrounding vapour limits the enrichment of the rain droplets during evaporation. Recently, Vimeux and Risi (2021) evaluated precipitation in the Andes Mountains in Bolivia and found that S75 was not sufficient to explain the isotope observations of rainfall in this region.…”

Section: Introductionmentioning

confidence: 99%

Suspended in sound: New constraints on isotopic fractionation of falling hydrometeors using acoustically levitated water droplets

Bellagamba

Berkelhammer

Weber

et al. 2023

Hydrological Processes

View full text Add to dashboard Cite

The isotopic composition of precipitation (δ 18 O, δ 2 H, and δ 17 O) is affected by evaporation and exchange as hydrometeors descend. These processes can significantly alter the isotopic ratio of precipitation relative to its initial condensation state in the cloud yet are exceedingly difficult to study in situ. The most widely utilized model for droplet-atmosphere exchange was derived from controlled experiments where droplets were suspended by forced air in a narrow glass tube-a design that manipulated the structure of the boundary layer around the droplet. Here, we provide a novel experimental test of atmosphere-hydrometeor isotopic exchange using the mechanism of acoustic levitation, where sound waves are projected vertically to levitate droplets in free-flowing ambient air. We present results from a series of droplet levitation experiments where the droplets' surface temperatures were measured by a thermal camera and the background atmospheric isotope concentration was measured via cavity-ringdown spectroscopy, providing a high degree of constraint on the fractionation conditions. We show that isotope enrichment of the suspended droplets met first order expectations based on existing models. However, to account for the slope of δ 18 O versus δ 2 H (i.e., the meteoric water line) and deuterium excess of the droplets as they evolved, we had to modify the existing model for dropletatmosphere exchange to account for the fact that some portion of the evaporative flux from the droplet remained present in the boundary layer around the droplet leading to an evolving feedback between droplet and the atmosphere-that is, a quasi closed-system effect. The isotopic enrichment of the boundary layer surrounding the droplet as a consequence of the closed-system dynamics, drives more rapid δ 18 O isotope enrichment relative to δ 2 H of the droplet compared to what is predicted using an open system model. Although these were controlled experiments, they illustrate important dynamics regarding the isotopic signature of feedbacks between droplet evaporation and atmospheric humidity.

show abstract

“…Precipitation samples plotting below the GMWL are indications of re-evaporation of raindrops during precipitation events (Banda, Rivett, Zavison, Kamtukule, & Kalin, 2021). Small size raindrops of stratiform precipitation are inclined to kinetic fractionation under the cloud base, favoring exchange with surrounding air and re-evaporation (Li, Tang, & Cui, 2021). The notable deviation from the GWML of the Kunming precipitations, with a regression line equation of δ 2 H=6.56 δ 18 O-2.9 would be from significant evaporative enrichment occurred during rainfall falling process (2021).…”

Section: Comparison Of Antananarivo Data With Regional and Internatio...mentioning

confidence: 99%

Water Stable Isotope Composition of Precipitations at Two Stations in Antananarivo-Madagascar: A Comparative Study

Ramaroson¹,

Rajaobelison²,

Fareze³

et al. 2022

ESR

View full text Add to dashboard Cite

In the “Global Network of Isotopes in Precipitation” database, Antananarivo has two distinct datasets from two stations. Thirty-four years separate the two datasets. This study aims on the one hand to depict the variations of the water stable isotopes composition of precipitations from the two stations and understand their origins, mainly in relation to meteorological factors. On the other hand, the Antananarivo data are compared with regional and international data to identify other sources of isotope composition variability in precipitation. Isotope records showed that after thirty-four-year gap, summer and winter (the two main seasons) precipitations are more enriched in heavy isotopes. The precipitation amount fluctuation would mostly contribute to this temporal variation. Opposite to summer and winter precipitations, inter-season rainfalls have similar isotope values after thirty-four years. The two stations are geographically close and the spatial aspect is therefore negligible since there are no latitude nor altitude effects on the isotope composition of precipitations. Regarding the second order parameter d-excess, the monthly mean values from both stations are higher than 100/00 and could indicate moisture recycling. The comparison with regional/international data showed that the isotope variability in precipitation is primarily due to precipitation amount effect, different moisture source, the stations distance from it and the change of meteorological factors along the moisture trajectory.

show abstract

Intra-Event Isotopic Changes in Water Vapor and Precipitation in South China

Cited by 8 publications

References 71 publications

High‐resolution temporal dynamics of intra‐storm isotopic composition of stemflow and throughfall in a Mediterranean Scots pine forest

High‐resolution temporal dynamics of intra‐storm isotopic composition of stemflow and throughfall in a Mediterranean Scots pine forest

Suspended in sound: New constraints on isotopic fractionation of falling hydrometeors using acoustically levitated water droplets

Water Stable Isotope Composition of Precipitations at Two Stations in Antananarivo-Madagascar: A Comparative Study

Contact Info

Product

Resources

About