Distribution of oxygen-18 and deuterium in river waters across the United States
Distribution of oxygen-18 and deuterium in river waters across the United States
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DOI：
10.1002/hyp.217
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发表时间：
2001-05-01
影响因子：
3.2
通讯作者：
Coplen, TB
中科院分区：
文献类型：
--
作者：
Kendall, C;Coplen, TB
现代水文循环中同位素模式的信息有限，阻碍了大陆古气候和古水文的重建。为了纠正这种情况，并为其他同位素水文学研究提供基线数据，对美国地质勘探局国家河流质量核算网络（NASQAN）和水文基准网络（HBN）内391个选定地点的4800多个深度和宽度综合河流样本进行了分析，以确定O-18三角洲和H-2三角洲（http：//water.usgs.gov/pubs/ofr/ofr00-160/pdf/ofr00-160.pdf）。在1984年至1987年的2.5至3年间，每两个月或每季度对每个地点进行一次采样。该数据集作为美国现代降水同位素组成的代理的能力得到了河流数据集与相邻降水监测点的同位素组成之间的良好一致性，δ O-18和δ H-2分布的强烈空间一致性，同位素组成与气候参数的良好相关性，从三角洲H-2 = 8.11三角洲O-18 + 8.99（r（2）= 0.98）的48个相邻州的样品的未加权分析产生的“国家”大气降水线（MWL）和来自全球降水同位素网络（GNIP）的未加权全球MWL之间的良好一致性根据国际原子能机构和世界气象组织（气象组织）的数据，Δ H-2 = 8.17 Δ O-18 + 10.35。国家大气降水线是由当地不同条件下的水样组成的，当地大气降水线（LMWLs）通常坡度较低。相邻站点通常具有相似的LMWL，允许将数据集合并为区域MWL。区域MWL的斜率可能反映了当地空气质量的湿度，这赋予了独特的蒸发同位素签名的降雨，因此流样品。在美国东半部、沿着西北海岸和科罗拉多高原，氘过量值范围为6 - 15%。在美国其他地区，这些值的范围从-2%至6%，与区域干旱有很强的空间相关性。河流样本成功地整合了气象循环中的空间变异性，并提供了有关美国大气沃茨水三角洲O-18和三角洲H-2值空间分布的最佳可用数据集。
Reconstruction of continental palaeoclimate and palaeohydrology is currently hampered by limited information about isotopic patterns in the modern hydrologic cycle. To remedy this situation and to provide baseline data for other isotope hydrology studies, more than 4800, depth- and width-integrated, stream samples from 391 selected sites within the USGS National Stream Quality Accounting Network (NASQAN) and Hydrologic Benchmark Network (HBN) were analysed for delta O-18 and delta H-2 (http://water.usgs.gov/pubs/ofr/ofr00-160/pdf/ofr00-160.pdf). Each site was sampled bimonthly or quarterly for 2.5 to 3 years between 1984 and 1987. The ability of this dataset to serve as a proxy for the isotopic composition of modem precipitation in the USA is supported by the excellent agreement between the river dataset and the isotopic compositions of adjacent precipitation monitoring sites, the strong spatial coherence of the distributions of delta O-18 and delta H-2, the good correlations of the isotopic compositions with climatic parameters, and the good agreement between the 'national' meteoric water line (MWL) generated from unweighted analyses of samples from the 48 contiguous states of delta H-2 = 8.11 delta O-18 + 8.99 (r(2) = 0.98) and the unweighted global MWL of sites from the Global Network for Isotopes in Precipitation (GNIP) of the International Atomic Energy Agency and the World Meteorological Organization (WMO) of delta H-2 = 8.17 delta O-18 + 10.35. The national MWL is composed of water samples that arise in diverse local conditions where the local meteoric water lines (LMWLs) usually have much lower slopes. Adjacent sites often have similar LMWLs, allowing the datasets to be combined into regional MWLs. The slopes of regional MWLs probably reflect the humidity of the local air mass, which imparts a distinctive evaporative isotopic signature to rainfall and hence to stream samples. Deuterium excess values range from 6 to 15% in the eastern half of the USA, along the northwest coast and on the Colorado Plateau. In the rest of the USA, these values range from -2 to 6%, with strong spatial correlations with regional aridity. The river samples have successfully integrated the spatial variability in the meteorological cycle and provide the best available dataset on the spatial distributions of delta O-18 and delta H-2 values of meteoric waters in the USA.