Terrestrial‐originated submarine groundwater discharge through deep multilayered aquifer systems beneath the seafloor
Terrestrial‐originated submarine groundwater discharge through deep multilayered aquifer systems beneath the seafloor
复制标题
DOI：
10.1002/hyp.10163
复制
发表时间：
2015-01
影响因子：
3.2
通讯作者：
Qiaona Guo;Hailong Li
中科院分区：
文献类型：
--
作者：
Qiaona Guo;Hailong Li
摩尔估计，在南大西洋湾600 km长的海岸线上，有大量的海底地下水排放量（SGD），约为1000 m3 day−1 m−1（全球生物地球化学循环，2010 b，24，GB 4005，doi：10.1029/2009 GB 003747）。然而，在估计SGD的净陆源地下水补给百分比方面存在很大的不确定性。此外，以前的大多数研究考虑了沿海表层含水层的同质情况。在这里，我们通过一个多层的海底含水层系统，其中包括两个承压含水层和两个半渗透层，调查了陆地起源的SGD。内陆补给包括代表年平均的恒定部分和代表其季节变化的周期部分。推导出一个解析解，并用于分析南大西洋湾Winyah Bay样带沿着多层含水层中陆源SGD的分布。据发现，从上部含水层的SGD区的宽度范围从~0.8到~8.0 km，取决于海底半渗透层的渗漏。当海岸线上的上层含水层水头高于平均海平面1.0 m时，该含水层的SGD为1.82- 18.3 m3 day−1 m−1，因为海底半渗透层的渗漏量在0.001到0.1 day−1之间变化，这为大量陆源SGD提供了相当大的可能性。分析模型预测的季节性陆源SGD变化为摩尔观测到的226 Ra的季节性变化提供了一致的解释（Journal of Geophysics，2007，112，C10013，doi：10.1029/2007 JC 004199）。下含水层对SGD的贡献仅为上含水层的1.2-12%。版权所有© 2014约翰威利父子有限公司.
A large quantity of submarine groundwater discharge (SGD) of about 1000 m3 day−1 m−1 of the 600‐km‐long shoreline of South Atlantic Bight has been estimated by Moore (Global Biogeochemical Cycles, 2010b, 24, GB4005, doi:10.1029/2009GB003747). However, there is great uncertainty in estimating the percentage of net, land‐originated groundwater recharge of SGD. Moreover, most previous studies considered the homogeneous case for the coastal superficial aquifers. Here, we investigated the terrestrial‐originated SGD through a multilayered submarine aquifer system, which comprises two confined aquifers and two semi‐permeable layers. The inland recharge includes a constant part representing the annual average and a periodical part representing its seasonal variation. An analytical solution was derived and used to analyse the distributions of the terrestrial‐originated SGD from the multilayered aquifers along the Winyah Bay transect, South Atlantic Bight. It is found that the width of the zone of SGD from the upper aquifer ranges from ~0.8 to ~8.0 km depending on the leakance of the seabed semi‐permeable layer. A head of the upper aquifer at a coastline 1.0 m higher than the mean sea level will cause a SGD of 1.82– 18.3 m3 day−1 m−1 from that aquifer as the seabed semi‐permeable layer's leakance varies from 0.001 to 0.1 day−1, providing considerable possibility for considerable land‐originated SGD. Seasonal terrestrial‐originated SGD variations predicted by the analytical model provide consistent explanation of the seasonal variation of 226Ra observed by Moore (Journal of Geophysics, 2007, 112, C10013, doi:10.1029/2007JC004199). The contribution of the lower aquifer to SGD is only 1.2–12% of that of the upper aquifer. Copyright © 2014 John Wiley & Sons, Ltd.