DOI: 10.1016/j.epsl.2018.09.028
Scopus记录号: 2-s2.0-85054323498
论文题名: Spatial-seasonal patterns reveal large-scale atmospheric controls on Asian Monsoon precipitation water isotope ratios
作者: Cai Z. ; Tian L. ; Bowen G.J.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 503 起始页码: 158
结束页码: 169
语种: 英语
英文关键词: Asian monsoon
; convection
; moisture source
; oxygen isotope
; precipitation
; seasonal variation
英文摘要: Correlated seasonal variation in precipitation amount and its oxygen isotope ratios (δ18O) has long been observed and frequently invoked in the interpretation of paleo-δ18O records from the Asian Monsoon (AM) region. However, the underlying cause of the observed seasonal δ18O variation is still under debate. Precipitation δ18O values show a single, consistent seasonal pattern across the region, with high values in pre-monsoon (late-spring to early-summer) and low values in the monsoon mature (mid- to late-summer) periods. We tested three hypotheses that may give rise to the measured precipitation δ18O pattern, involving variation in: 1) local precipitation, 2) moisture sources, and 3) convection in moisture source regions. We show that seasonal precipitation amounts across the AM region exhibit two pattern types: pre-monsoon peak or monsoon mature peak, and thus do not provide a consistent explanation for the isotopic pattern. We test the hypotheses that changing moisture sources or moisture source isotope ratios drive the seasonal isotopic pattern using a combination of Lagrangian moisture source attribution and output from an isotope-enabled General Circulation Model (LMDZ4), but find little seasonal variation in moisture sources; that which does exist is not consistent with the observed isotopic change. Instead, we show that the precipitation δ18O transition from pre-monsoon to monsoon mature stage is correlated with intensification of convective activity in moisture source regions, which is the result of monsoon establishment and northward migration of the Intertropical Convergence Zone (ITCZ). We propose that light water vapor, transferred to the lower-troposphere through downdrafts and evaporation of rain in the vicinity of intense convection, is advected to the AM region and labels precipitation during the monsoon mature period. These results demonstrate that precipitation δ18O in the AM region more strongly reflect large-scale atmospheric dynamics than local precipitation amount or moisture source, guiding the interpretation of paleo-isotope data from this region. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109629
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China; Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112, United States; Institute of International Rivers and Eco-security, Yunnan University, Kunming, Yunnan 650091, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, 100101, China; College of Resource and Environment, University of Chinese Academy of Sciences, Beijing, 100190, China; University of Chinese Academy of Sciences, Beijing, 100049, China
Recommended Citation:
Cai Z.,Tian L.,Bowen G.J.. Spatial-seasonal patterns reveal large-scale atmospheric controls on Asian Monsoon precipitation water isotope ratios[J]. Earth and Planetary Science Letters,2018-01-01,503