期刊
HOLOCENE
卷 20, 期 6, 页码 837-848出版社
SAGE PUBLICATIONS LTD
DOI: 10.1177/0959683610365940
关键词
AMS radiocarbon dating; carbon isotopes; hydrological reconstruction; Juniperus procera; Sub-Saharan Africa; tropical dendrochronology
资金
- Swansea University
- Royal Geographical Society [GFG 6/07]
- Dudley Stamp Memorial Trust (Royal Society)
- Quaternary Research Association
- Association for Tree-ring Research
- University of Arizona
- EU [017008-2]
- UK NERC [NE/B501504]
- Nicolaus Copernicus University
- NWO/MEERVOUD [83605030]
- Ethiopian Orthodox Church
- Gondar Tourist Office
- Amhar governmental office for agriculture and rural development
- North Gondar governmental office for agriculture and rural development
- Debark governmental office for agriculture and rural development
- Dabat governmental office for agriculture and rural development
- Gondar governmental office for agriculture and rural development
- Natural Environment Research Council [NE/B501504/1] Funding Source: researchfish
Most of the water in the River Nile originates from monsoonal rainfall over the Ethiopian Highlands. Despite warnings of future climate change, little is known about the historical variability in this supply, particularly at annual resolution. Development of tree-ring records in this region has been limited by the occurrence of bi- or multimodal rainfall regimes, causing the development of multiple growth rings that cannot be dated with confidence. In this study, we identified annual rings in 30 Juniperus procera trees from northwest Ethiopia by dendrochronology and AMS radiocarbon dating. Carbon isotope ratios (4 series) and ring widths (73 series) were measured. The carbon isotope series did not contain strong trends possibly attributable to increased anthropogenic atmospheric CO2 concentrations or the juvenile effect. Both carbon isotope values and ring widths were strongly correlated with Blue Nile baseflow, and from composite chronology indices (r=0.75, p < 0.01), a preliminary reconstruction of Blue Nile baseflow back to ad 1836 was developed. Subsample signal strength remained above 0.85 for most of the reconstruction. Uncertainty bands were relatively narrow and the reliability of the preliminary reconstruction was confirmed by correspondence with reported years of drought and famine. The preliminary reconstruction is characterized by an exceptional decline in baseflow during the late ad 1960s. Flows recovered during the late 1990s. Additional sampling is advised to increase replication, spatial coverage and length of the preliminary reconstruction.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据