The effect of moisture source and synoptic conditions on precipitation isotopes in arid central Asia

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dc.contributor.authorWang, SJen_AU
dc.contributor.authorZhang, MJen_AU
dc.contributor.authorCrawford, Jen_AU
dc.contributor.authorHughes, CEen_AU
dc.contributor.authorDu, MXen_AU
dc.contributor.authorLiu, XMen_AU
dc.date.accessioned2021-04-20T01:38:54Zen_AU
dc.date.available2021-04-20T01:38:54Zen_AU
dc.date.issued2017-02-22en_AU
dc.date.statistics2021-03-05en_AU
dc.description.abstractThe stable isotopic (2H/1H and 18O/16O) composition of precipitation has been used for a variety of hydrological and paleoclimate studies, a starting point for which is the behaviour of stable isotopes in modern precipitation. To this end, daily precipitation samples were collected over a 7‐year period (2008–2014) at a semi‐arid site located at the Macquarie Marshes, New South Wales (Australia). The samples were analysed for stable isotope composition, and factors affecting the isotopic variability were investigated. The best correlation between δ18O of precipitation was with local surface relative humidity. The reduced major axis precipitation weighted local meteoric water line was δ2H = 7.20 δ18O + 9.1. The lower slope and intercept (when compared with the Global Meteoric Water Line) are typical for a warm dry climate, where subcloud evaporation of raindrops is experienced. A previously published model to estimate the degree of subcloud evaporation and the subsequent isotopic modification of raindrops was enhanced to include the vertical temperature and humidity profile. The modelled results for raindrops of 1.0 mm radius showed that on average, the measured D‐excess (=δ2H − 8 δ18O) was 19.8‰ lower than that at the base of the cloud, and 18% of the moisture was evaporated before ground level (smaller effects were modelled for larger raindrops). After estimating the isotopic signature at the base of the cloud, a number of data points still plotted below the global meteoric water line, suggesting that some of the moisture was sourced from previously evaporated water. Back trajectory analysis estimated that 38% of the moisture was sourced over land. Precipitation samples for which a larger proportion of the moisture was sourced over land were 18O and 2H‐enriched in comparison to samples for which the majority of the moisture was sourced over the ocean. The most common weather systems resulting in precipitation were inland trough systems; however, only East Coast Lows contributed to a significant difference in the isotopic values. Copyright © 2016 Australian Nuclear Science and Technology Organisation. Hydrological Processes. © 2016 John Wiley & Sons, Ltd. (Open access)en_AU
dc.identifier.citationWang, S., Zhang, M., Crawford, J., Hughes, C. E., Du, M., & Liu, X. (2017). The effect of moisture source and synoptic conditions on precipitation isotopes in arid central Asia. Journal of Geophysical Research: Atmospheres, 122(5), 2667-2682. doi:10.1002/2015JD024626en_AU
dc.identifier.issn2169-897Xen_AU
dc.identifier.issue5en_AU
dc.identifier.journaltitleJournal of Geophysical Research: Atmospheresen_AU
dc.identifier.pagination2667-2682en_AU
dc.identifier.urihttps://doi.org/10.1002/hyp.10885en_AU
dc.identifier.urihttps://apo.ansto.gov.au/dspace/handle/10238/10673en_AU
dc.identifier.volume122en_AU
dc.language.isoenen_AU
dc.publisherAmerican Geophysical Unionen_AU
dc.subjectStable isotopesen_AU
dc.subjectOxygenen_AU
dc.subjectAtmospheric precipitationsen_AU
dc.subjectNew South Walesen_AU
dc.subjectAustraliaen_AU
dc.subjectHumidityen_AU
dc.subjectEvaporationen_AU
dc.subjectRain wateren_AU
dc.subjectWeatheren_AU
dc.subjectAsiaen_AU
dc.titleThe effect of moisture source and synoptic conditions on precipitation isotopes in arid central Asiaen_AU
dc.typeJournal Articleen_AU
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