Stable isotopic composition of precipitation in the semi-arid north-central portion of the US Great Plains
Stable isotopic composition of precipitation in the semi-arid north-central portion of the US Great Plains
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DOI：
10.1016/s0022-1694(00)00316-4
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发表时间：
2000-11
影响因子：
6.4
通讯作者：
F. Harvey;J. Welker
中科院分区：
文献类型：
--
作者：
F. Harvey;J. Welker
在有数据的情况下，水文研究可使用稳定的氧和氢同位素来调查地下水/地表水的相互作用、地下水补给和平流/扩散迁移，以估计地下水年龄或揭示古水文学。这类研究要求了解降水的同位素组成，因为降水是地下水和地表水系统的主要输入。美国大平原中北部的半干旱地区缺乏降水的氧-18（δ 18 O）和氘（δ 2 H）数据，因此需要在整个地区建立额外的大气降水线作为同位素输入函数，并更好地了解控制降水中氧和氢同位素比率的同位素气候联系。本研究考察了1989年至1994年半干旱大平原中北部内布拉斯加州北普拉特附近一个代表性地点降水的δ 18 O和δ 2 H组成。氧-18值范围为-30.5至+1.7‰。氘值范围为−228至+11‰。北普拉特站的年算术平均值分别为−9.8和−71‰。6年间，δ 18 O和δ 2 H的加权年平均值分别为-9.6和-69 ‰。北普拉特值表明冬、夏季降水之间存在较强的同位素富集现象，月平均值为0.54‰/℃时，δ 18 O-T的相关系数r2=0.845。当地大气降水线为δ 2 H =7.66δ 18 O +4.96。
Where data are available, hydrologic studies may use stable oxygen and hydrogen isotopes to investigate, groundwater/surface water interaction, groundwater recharge and advective/diffusive transport, to estimate groundwater ages or to unravel paleohydrology. Such studies require that the isotopic composition of precipitation be known, as precipitation is a major input to groundwater and surface water systems. Oxygen-18 (δ18O) and deuterium (δ2H) data for precipitation are lacking for the semi-arid portion of the north-central Great Plains of the US, and thus there is need to establish additional meteoric water lines as isotope input functions across the region, as well as to develop better understanding of the isotopic climate linkages that control oxygen and hydrogen isotope ratios in precipitation. This study examines the δ18O and δ2H composition of precipitation for a representative site near North Platte, Nebraska in the semi-arid north-central Great Plains during the years 1989 through 1994. Oxygen-18 values range from −30.5 to +1.7‰. Deuterium values range from −228 to +11‰. Yearly arithmetic mean values for the North Platte station are −9.8 and −71‰, respectively. Weighted yearly means for δ18O and δ2H over the 6-year period were −9.6 and −69‰, respectively. North Platte values show a strong isotopic enrichment between winter and summer precipitation, and a strong δ18O–T correlation r2=0.845 for mean monthly values of 0.54‰ per degree Celsius. The local meteoric water line for the site is δ2H=7.66δ18O+4.96.