DOI: 10.1016/j.gloplacha.2016.02.001
论文题名: Calibration of speleothem δ18O records against hydroclimate instrumental records in Central Brazil
作者: Moquet J.S. ; Cruz F.W. ; Novello V.F. ; Stríkis N.M. ; Deininger M. ; Karmann I. ; Santos R.V. ; Millo C. ; Apaestegui J. ; Guyot J.-L. ; Siffedine A. ; Vuille M. ; Cheng H. ; Edwards R.L. ; Santini W.
刊名: Global and Planetary Change
ISSN: 0921-8181
出版年: 2016
卷: 139 起始页码: 151
结束页码: 164
语种: 英语
英文关键词: Central Brazil
; Climate calibration
; SAMS-SACZ
; Speleothem
; Stable isotopes
Scopus关键词: Atmospheric thermodynamics
; Calibration
; Caves
; Isotopes
; Rain
; Seepage
; Central brazils
; Isotopic composition
; Precipitation patterns
; Precipitation variability
; Sams
; Speleothem
; Stable isotopes
; Stable oxygen isotope ratio
; Precipitation (meteorology)
英文摘要: δ18O in speleothems is a powerful proxy for reconstruction of precipitation patterns in tropical and sub-tropical regions. The aim of this study is to calibrate the δ18O record of speleothems against historical precipitation and river discharge data in central Brazil, a region directly influenced by the Southern Atlantic Convergence Zone (SACZ), a major feature of the South American Monsoon System (SAMS). The present work is based on a sub-annual resolution speleothem record covering the last 141 years (the period between the years 1870 and 2011) from a cave in central Brazil. The comparison of this record with instrumental hydroclimate records since 1921 allows defining a strong relationship between precipitation variability and stable oxygen isotope ratios from speleothems. The results from a monitoring program of climatic parameters and isotopic composition of rainfall and cave seepage waters performed in the same cave, show that the rain δ18O variability is dominated by the amount effect in this region, while δ18O drip water remains almost constant over the monitored period (1.5 years). The δ18O of modern calcite, on the other hand, shows clear seasonal variations, with more negative values observed during the rainy season, which implies that other factors also influence the isotopic composition of carbonate. However, the relationship between δ18O of carbonate deposits and rainwater is supported by the results from the comparison between speleothem δ18O records and historical hydroclimate records. A significant correlation between speleothem δ18O and monsoon rainfall variability is observed on sub-decadal time scales, especially for the monsoon period (DJFM and NDJFM), once the rainfall record have been smoothed with a 7-9 years running mean. This study confirms that speleothem δ18O is directly associated with monsoon rainfall variability in central Brazil. The relationship between speleothem δ18O records and hydroclimatic historical records allows approximation of the absolute changes in mean annual rainfall during the last millennia in the SACZ/SAMS domain. © 2016. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84959318995&doi=10.1016%2fj.gloplacha.2016.02.001&partnerID=40&md5=35bb890ace42450a1f34062cad3c5439
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/11701
Appears in Collections: 全球变化的国际研究计划 气候变化与战略
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作者单位: Instituto de Geociências, Universidade de São Paulo, São Paulo, Brazil
Recommended Citation:
Moquet J.S.,Cruz F.W.,Novello V.F.,et al. Calibration of speleothem δ18O records against hydroclimate instrumental records in Central Brazil[J]. Global and Planetary Change,2016-01-01,139.