Dynamic Steady State in Coastal Aquifers Is Driven by Multi‐Scale Cyclical Processes, Controlled by Aquifer Storativity
Dynamic Steady State in Coastal Aquifers Is Driven by Multi‐Scale Cyclical Processes, Controlled by Aquifer Storativity
复制标题
DOI：
10.1029/2022gl098599
复制
发表时间：
2022-05
影响因子：
5.2
通讯作者：
A. Paldor;R. Frederiks;H. Michael
中科院分区：
文献类型：
--
作者：
A. Paldor;R. Frederiks;H. Michael
沿海含水层为全球近一半的人口提供淡水，但它们受到盐碱化的威胁。盐度通常是假设稳态来估计的，忽略了周期性强迫对平均盐度分布的影响。在这里，数值模拟被用来测试这个假设。海平面（SL）的多尺度波动被模拟，从潮汐到冰川周期。结果表明，与平均SL产生的稳态分布相比，高频波动会改变平均盐度。低频强迫产生的差异，目前的盐度估计与不考虑周期性强迫由于过冲效应。这意味着，在假定稳定状态条件下，可能会错误地估计沿海含水层的盐度，因为目前的分布可能是动态稳定状态的一部分，包括多个时间尺度上的强迫。此外，通常被忽视的含水层存储特性可以强烈地控制平均盐度分布。这对管理脆弱的沿海地下水资源和水文地质模型的校准具有重要意义。
Coastal aquifers supply freshwater to nearly half the global population, yet they are threatened by salinization. Salinities are typically estimated assuming steady‐state, neglecting the effect of cyclical forcings on average salinity distributions. Here, numerical modeling is used to test this assumption. Multi‐scale fluctuations in sea level (SL) are simulated, from tides to glacial cycles. Results show that high‐frequency fluctuations alter average salinities compared with the steady‐state distribution produced by average SL. Low‐frequency forcing generates discrepancies between present‐day salinities estimated with and without considering the cyclical forcing due to overshoot effects. This implies that salinities in coastal aquifers may be erroneously estimated when assuming steady‐state conditions, since present distributions are likely part of a dynamic steady state that includes forcing on multiple timescales. Further, typically neglected aquifer storage characteristics can strongly control average salinity distributions. This has important implications for managing vulnerable coastal groundwater resources and for calibration of hydrogeological models.