Periodic forcing in composite aquifers
Periodic forcing in composite aquifers
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DOI：
10.1016/s0309-1708(98)00037-2
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发表时间：
1999-02
影响因子：
4.7
通讯作者：
M. Trefry
中科院分区：
文献类型：
--
作者：
M. Trefry
长期以来，对测量水头的周期性分量的观测一直被用来估计含水层扩散率。对于正弦边界波动通过均匀一维含水层的传播，通常使用线性微分方程的众所周知的解来进行估计。最近的现场数据表明，在几个例子中，均匀含水层的解决方案，给不一致的估计含水层的扩散从测量的潮汐滞后和衰减。本文提出了空间非均匀一维含水层中潮汐传播的新的代数解。在现有的均质含水层解的基础上，提出了由任意（有限）数量的连续均质次含水层组成的复合含水层的综合解，并满足正弦线性边界条件。笛卡尔和径向坐标系被认为是。属性的解决方案，包括快速相移和衰减效果，进行了讨论，并指出其实际意义。通过分潮分析，还研究了模态频散对潮汐波形的影响。它表明，对于多成分的潮汐强迫，测得的头部振荡的峰值高度似乎可以增加，相位滞后似乎减少，与强迫边界的距离，除非成分被分离，并被认为是孤立的。
Observations of periodic components of measured heads have long been used to estimate aquifer diffusivities. The estimations are often made using well-known solutions of linear differential equations for the propagation of sinusoidal boundary fluctuations through homogeneous one-dimensional aquifers. Recent field data has indicated several instances where the homogeneous aquifer solutions give inconsistent estimates of aquifer diffusivity from measurements of tidal lag and attenuation. This paper presents new algebraic solutions for tidal propagation in spatially heterogeneous one-dimensional aquifers. By building on existing solutions for homogeneous aquifers, comprehensive solutions are presented for composite aquifers comprising of arbitrary (finite) numbers of contiguous homogeneous sub-aquifers and subject to sinusoidal linear boundary conditions. Both Cartesian and radial coordinate systems are considered. Properties of the solutions, including rapid phase shifting and attenuation effects, are discussed and their practical relevance noted. Consequent modal dispersive effects on tidal waveforms are also examined via tidal constituent analysis. It is demonstrated that, for multi-constituent tidal forcings, measured peak heights of head oscillations can seem to increase, and phase lags seem to decrease, with distance from the forcing boundary unless constituents are separated and considered in isolation.