DOI: 10.1029/2018JD028470
Scopus记录号: 2-s2.0-85050397513
论文题名: Precipitation Origins and Key Drivers of Precipitation Isotope (18O, 2H, and 17O) Compositions Over Windhoek
作者: Kaseke K.F. ; Wang L. ; Wanke H. ; Tian C. ; Lanning M. ; Jiao W.
刊名: Journal of Geophysical Research: Atmospheres
ISSN: 2169897X
出版年: 2018
卷: 123, 期: 14 起始页码: 7311
结束页码: 7330
语种: 英语
英文关键词: climate change
; ecohydrology
; HYSPLIT
; Namibia
; rainfall
; stable isotopes
英文摘要: Southern 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. ©2018. American Geophysical Union. All Rights Reserved.
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/113503
Appears in Collections: 气候减缓与适应
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作者单位: Department of Earth Sciences, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States; Geology Department, University of Namibia, Windhoek, Namibia
Recommended Citation:
Kaseke K.F.,Wang L.,Wanke H.,et al. Precipitation Origins and Key Drivers of Precipitation Isotope (18O, 2H, and 17O) Compositions Over Windhoek[J]. Journal of Geophysical Research: Atmospheres,2018-01-01,123(14)