Precipitation Origins and Key Drivers of Precipitation Isotope (18O, 2H, and 17O) Compositions Over Windhoek

dc.contributor.authorKaseke, Kudzai Farai
dc.contributor.authorWang, Lixin
dc.contributor.authorWanke, Heike
dc.contributor.authorTian, Chao
dc.contributor.authorLanning, Matthew
dc.contributor.authorJiao, Wenzhe
dc.contributor.departmentEarth Sciences, School of Scienceen_US
dc.date.accessioned2018-08-30T18:21:04Z
dc.date.available2018-08-30T18:21:04Z
dc.date.issued2018
dc.description.abstractSouthern African climate is characterized by large precipitation variability, and model precipitation estimates can vary by 70% during summer. This may be partly attributed to underestimation and lack of knowledge of the exact influence of the Atlantic Ocean on precipitation over the region. The current study models trajectories of precipitation events sampled from Windhoek (2012–2016), coupled with isotopes (δ18O, δ2H, δ17O, d, and δ′17O‐δ′18O) to determine key local drivers of isotope compositions as well as infer source evaporative conditions. Multiple linear regression analyses suggest that key drivers of isotope compositions (relative humidity, precipitation amount, and air temperature) account for 47–53% of δ18O, δ2H, and δ17O variability. Surprisingly, precipitation δ18O, δ2H, and δ17O were independent of precipitation type (stratiform versus convective), and this may be attributed to greater modification of stratiform compared to convective raindrops, leading to convergence of isotopes from these precipitation types. Trajectory analyses showed that 78% and 21% of precipitation events during the period originated from the Indian and South Atlantic Oceans, respectively. Although precipitation from the Atlantic Ocean was significantly enriched compared to that from the Indian Ocean (p < 0.05), d was similar, suggesting significant local modification (up to 55% of d variability). Therefore, d may not be a conservative tracer of evaporation conditions at the source, at least for Windhoek. The δ′17O‐δ′18O appeared to be a better alternative to d, consistent with trajectory analyses, and appeared to differentiate El Niño from non‐El Niño droughts. Thus, δ′17O‐δ′18O could be a novel tool to identify drought mechanisms.en_US
dc.eprint.versionAuthor's manuscripten_US
dc.identifier.citationKaseke, K. F., Wang, L., Wanke, H., Tian, C., Lanning, M., & Jiao, W. (2018). Precipitation origins and key drivers of precipitation isotope (18O, 2H, 17O) compositions over Windhoek. Journal of Geophysical Research: Atmospheres, 123 (14), 7311-7330. https://doi.org/10.1029/2018JD028470en_US
dc.identifier.urihttps://hdl.handle.net/1805/17252
dc.language.isoenen_US
dc.publisherAGUen_US
dc.relation.isversionof10.1029/2018JD028470en_US
dc.relation.journalJournal of Geophysical Research: Atmospheresen_US
dc.rightsPublisher Policyen_US
dc.sourceAuthoren_US
dc.subjectclimate changeen_US
dc.subjectecohydrologyen_US
dc.subjectHYSPLITen_US
dc.titlePrecipitation Origins and Key Drivers of Precipitation Isotope (18O, 2H, and 17O) Compositions Over Windhoeken_US
dc.typeArticleen_US
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