DOI: 10.1016/j.jhydrol.2020.124801
论文题名: Groundwater isotope ratios reflect convective and stratiform (paleo)precipitation fractions in Brazil
作者: Chang H.K. ; Gonçalves R.D. ; Aggarwal P.K. ; Stradioto M.R. ; Hespanhol E.C.B. ; Sturchio N.C. ; Romatschke U. ; Araguas L.J.A.
刊名: Journal of Hydrology
ISSN: 221694
出版年: 2020
卷: 585 语种: 英语
英文关键词: Convective and stratiform precipitation
; Groundwater isoscape
; South atlantic convergence zone
; Speleothems
; Stable isotopes
Scopus关键词: Groundwater
; Oxygen
; Precipitation (meteorology)
; Tropics
; Negative correlation
; Oxygen isotope records
; South atlantic convergence zones
; Speleothems
; Stable isotope ratios
; Stable isotopes
; Stratiform precipitation
; Subtropical latitudes
; Isotopes
英文摘要: The stable isotope ratios of oxygen and hydrogen in shallow groundwater reflect the long-term amount-weighted mean isotopic composition of precipitation. Here, we report the isotopic composition of more than 1000 shallow groundwater samples (age < ∼5,000 yr) across continental Brazil. Recent studies of global precipitation have shown a strong negative correlation between the isotopic compositions (e.g., δ18O values) and stratiform fractions of Brazilian precipitation, with geospatial correspondence to the South Atlantic convergence zone pattern. This isotope-precipitation type geospatial correlation is also reflected in the isotopic compositions of shallow groundwaters, and speleothem records from the region show small variations in δ18O values, implying general climatic stability in this region during the past few millennia. We propose that shallow groundwater isotopic compositions reflect bulk proportions of convective and stratiform fractions in precipitation and could thus be useful in conjunction with groundwater dating as proxy archives to characterize past changes in the proportions of convective and stratiform precipitation in tropical and subtropical latitudes. This groundwater isotope-precipitation type relationship could also have broader implications when considered for paleoclimatic interpretation of oxygen isotope records in dated speleothems from other locations. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/158163
Appears in Collections: 气候变化与战略
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作者单位: São Paulo State University, UNESP, Dept. of Applied Geology and Basin Studies Laboratory (LEBAC), Rio Claro, Brazil; São Paulo State University, UNESP, Environmental Studies Center (CEA) and Basin Studies Laboratory (LEBAC), Rio Claro, Brazil; Isotope Hydrology Section, International Atomic Energy Agency, A1400 Vienna, Austria; University of Delaware, Dept. of Earth Sciences, Newark, DE 19716, United States; Earth Observing Laboratory, National Center for Atmospheric Research, Boulder, CO, United States
Recommended Citation:
Chang H.K.,Gonçalves R.D.,Aggarwal P.K.,et al. Groundwater isotope ratios reflect convective and stratiform (paleo)precipitation fractions in Brazil[J]. Journal of Hydrology,2020-01-01,585