检索结果-南通市图书馆

Climatic significance of stable carbon isotope in tree rings of Abies spectabibis in southeastern Tibet

在线全文

学校读者我要写书评

暂无评论

引用

chinese Science Bulletin 2003年第18期48卷 2000-2004页

作者： liu {1. {2. {3. shao xuemei CHEN Tuo ren jiawen cold and {1. {2. Environment and {3. research institute Chinese Academy of SciencesLanzhou 730000China institute of Geographic {1. and Nature Resources {2. Chinese Academy of SciencesBeijing 100101China

The annually cross-dated stable carbon isotope of tree-ring a-cellulose of Abies spectabibis collected from the southeastern Tibetan Plateau is used to examine its rela-tionship with climatic parameters. The residual D13. series in treerings is constructed after removing the effects of age t{1.d and rising CO2. We found a close relationship between D13. in tree rings and the relative humidity of September—November of the previous year measured at the nearby Ny-ingchi Meteorological Station, albeit a strong 搇agged effect? Thus we developed a transfer function to reconstruct the autumn relative humidity for the Nyingchi region, which explained 3..9% of the total variance (p 1.. Our results suggest a high frequency and moderate amplitude variance of the relative humidity before 1.00, and the variance re-versed afterwards.

关键词： Abies spectabibis tree rings stable carbon isotope cli-matic reconstruction.

Foliar δ^(13.C and δ^(1.)N values of C_{1.plants in the Ethiopia Rift Valley and their environmental controls

在线全文

学校读者我要写书评

暂无评论

引用

chinese Science Bulletin 2007年第9期52卷 1265-1273页

作者： liu {1. ZHAO LiangJu GASAW Menassie GAO DengYi {2. {3. ren jiawen Key Laboratory of Cryosphere and Environment Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China Laboratory of Watershed Hydrology and Ecology Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China Department of Biology University of Addis Ababa Addis Ababa P. O. Box 62619 Ethiopia institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The foliar C and N stable isotopic compositions(δ 13. and δ 1.N) and the relationships between these compositions and {1. factors of C3.plants in the Ethiopia Rift Valley were investigated. There were three distribution patterns for foliar δ 13. with mean values of ?{3..7‰±0.4‰,?{3..7‰± 0.6‰,and ?{3..9‰± 1.{3. in cold-moist,temperate-moist,and arid-hot environments,respectively. The δ 1.N values ranged from ?1.4‰± 1.7‰ to 1..3.± 0.1.,with higher values under arid-hot conditions and the lowest values in plants growing at higher altitudes under cold-moist conditions. A strong negative relationship between mean annual precipitation and δ 1.N explained more than half of the observed variation in the δ 1.N values(r{3.= 0.54,P 1.;a modest positive relationship was also found between δ 1.N and tem-perature(r{3.= 0.3.3.P 1.. A weakly positive relationship existed between δ 13. and temperature,and changes in δ 13. values with precipitation and altitude followed quadratic curves. This suggests a shift in the effects of water and heat conditions caused by altitude on carbon isotopic discrimination.

关键词：埃塞俄比亚裂谷 C3.物叶片碳稳定同位素氮稳定同位素环境因素

Climatic significance of the stable carbon isotope composition of tree-ring cellulose:Comparison of chinese hemlock (Tsuga chinensis Pritz) and alpine pine (Pinus densata Mast) in a temperate-moist region of China

在线全文

学校读者我要写书评

暂无评论

引用

Science China Earth sciences 2007年第7期50卷 1076-1085页

作者： liu {1. {2. {3. WANG LiLi ZHAO LiangJu WU Pu CHEN Tuo qin dahe ren jiawen Key Laboratory of Cryosphere and Environment Cold and Arid Regions Environmental and Engineering Research InstituteChi-nese Academy of SciencesLanzhou 730000China institute of Geographical {1. and Natural Resources {2. Chinese Academy of SciencesBeijing 100101China institute of Tibetan Plateau {1. Chinese Academy of SciencesBeijing 100085China 4 Laboratory of Watershed Hydrology and EcologyCold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of SciencesLanzhou 730000China

In the reconstruction of past climate using stable carbon isotope composition (δ13.) in tree ring,the responses of the stable carbon composition (δ13.) of multiple tree species to {2. factors must be known detailedly. This study presented two δ13. series in annual tree rings for chinese hem-lock (Tsuga chinensis Pritz) and alpine pine (Pinus densata Mast),and investigated the relationships between climatic parameters and stable carbon discrimination (△13.) series,and evaluated the poten-tial of climatic reconstruction using △13. in both species,in a temperate-moist region of Chuanxi Pla-teau,China. The raw δ13. series of the two species was inconsistent,which may be a result of different responses caused by tree's inherent physiological differences. After removing the low-frequency ef-fects of CO2.concentration,the high-frequency (year-to-year) inter-series correlation of △13. was strong,indicating that △13. of the two tree species were controlled by common {2. conditions. The △13. series of the species were most significantly correlated with temperature and moisture stress,but in different periods and intensity between the species. During the physiological year,the impacts of temperature and moisture stress on △13. occur earlier for chinese hemlock (previous December to February for moisture stress and February to April for temperature,respectively) than for alpine pine (March to May for moisture stress and April to July for temperature,respectively). In addition,in temperate-moist regions,the control on △13. of single climatic parameter was not strongly dominant and the op-timal multiple regressions functions just explained the 3..5% variance of the total. Therefore,there is limited potential for using δ13. alone to identify clear,reliable climatic signals from two species.

关键词： temperate-moist region chinese hemlock Alpine pine inter-specific δ13. variability climatic significance