• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Ground water >Bias of Apparent Tracer Ages in Heterogeneous Environments
【24h】

Bias of Apparent Tracer Ages in Heterogeneous Environments

机译：异构环境中示踪剂年龄的偏差

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The interpretation of apparent ages often assumes that a water sample is composed of a single age. In heterogeneous aquifers, apparent ages estimated with environmental tracer methods do not reflect mean water ages because of the mixing of waters from many flow paths with different ages. This is due to nonlinear variations in atmospheric concentrations of the tracer with time resulting in biases of mixed concentrations used to determine apparent ages. The bias of these methods is rarely reported and has not been systematically evaluated in heterogeneous settings. We simulate residence time distributions (RTDs) and environmental tracers CFCs, SF_6, ~(85)Kr, and ~(39)Ar in synthetic heterogeneous confined aquifers and compare apparent ages to mean ages. Heterogeneity was simulated as both K-field variance (σ~2) and structure. We demonstrate that an increase in heterogeneity (increase in σ~2 or structure) results in an increase in the width of the RTD. In low heterogeneity cases, widths were generally on the order of 10 years and biases generally less than 10%. In high heterogeneity cases, widths can reach 100 s of years and biases can reach up to 100%. In cases where the temporal variations of atmospheric concentration of individual tracers vary, different patterns of bias are observed for the same mean age. We show that CFC-12 and CFC-113 ages may be used to correct for the mean age if analytical errors are small.
机译：表观年龄的解释通常假定水样由单个年龄组成。在非均质含水层中，用环境示踪法估算的表观年龄不能反映平均水龄，因为来自不同年龄的许多流动路径中的水混合在一起。这是由于示踪剂的大气浓度随时间发生非线性变化，导致用于确定表观年龄的混合浓度存在偏差。这些方法的偏差很少得到报道，并且尚未在异构环境中进行系统评估。我们在合成非均质承压含水层中模拟停留时间分布（RTD）和环境示踪剂CFC，SF_6，〜（85）Kr和〜（39）Ar，并将表观年龄与平均年龄进行比较。异质性被模拟为K场方差（σ〜2）和结构。我们证明异质性的增加（σ〜2或结构的增加）导致RTD宽度的增加。在低异质性情况下，宽度通常在10年量级，偏差通常小于10％。在高度异构的情况下，宽度可以达到100 s年，偏差可以达到100％。在个别示踪剂的大气浓度随时间变化的情况下，对于相同的平均年龄，观察到不同的偏差模式。我们显示，如果分析误差较小，则可以使用CFC-12和CFC-113年龄来校正平均年龄。

著录项

  • 来源
    《Ground water》 |2014年第2期|239-250|共12页
  • 作者

    James L. McCallum; Peter G. Cook; Craig T. Simmons; Adrian D. Werner;

  • 作者单位

    National Centre for Groundwater Research and Training, Flinders University, Adelaide, South Australia, Australia,School of the Environment, Flinders University, Adelaide,South Australia, Australia;

    National Centre for Groundwater Research and Training, Flinders University, Adelaide, South Australia, Australia,School of the Environment, Flinders University, Adelaide,South Australia, Australia;

    National Centre for Groundwater Research and Training, Flinders University, Adelaide, South Australia, Australia,School of the Environment, Flinders University, Adelaide,South Australia, Australia;

    National Centre for Groundwater Research and Training, Flinders University, Adelaide, South Australia, Australia,School of the Environment, Flinders University, Adelaide,South Australia, Australia;

  • 收录信息
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号