GroMoPo Metadata for Nubian Aquifer paleo-saltwater model

A numerical groundwater model of the Nubian Aquifer System was established to prove the influence of rising seawater levels on the groundwater salinity in northern Egypt over the last 140,000 years. In addition, the impact of a groundwater recharge scenario for these 140,000 years, involving climatic change, on the saltwater/freshwater interface was investigated. Saltwater intrusion induced by rising water levels of the Mediterranean Sea led to salinisation from the Mediterranean Sea to the Qattara depression. This modeling approach was supported by a density-driven model setup and calculation. The modelled saltwater/freshwater interfaces partially fitted the observed ones, especially in the southern half of the Qattara depression. In other parts of the northern Nubian Aquifer System, the ingression of salt water was modelled adequately, but in the west, small regions of the measured interface were not. The development in the Qattara depression (Egypt) and Sirte basin (Libya) were investigated in more detail. The different behaviour in the Sirte basin may be due to high evapotranspiration rates in some former periods, salt solutions from the pre-Quaternary layers or saltwater infiltration from sabkha-like recent salt-bearing sediments.本研究构建了努比亚含水层系统（Nubian Aquifer System）的数值地下水模型，旨在验证过去14万年间埃及北部海平面上升对区域地下水盐度的影响。此外，本研究针对该14万年间包含气候变化的地下水补给情景，探究了其对咸水/淡水界面的影响。由地中海海平面上升诱发的咸水入侵，使得盐分从地中海向盖塔拉洼地（Qattara depression）运移并引发区域盐渍化。本建模方案依托密度驱动流（density-driven）模型的构建与计算流程得以实现。模拟所得的咸水/淡水界面与实测界面存在部分吻合，尤其在盖塔拉洼地南部区域吻合度更佳。在努比亚含水层系统北部的其余区域，咸水入侵过程的模拟结果与实测数据吻合度较高，但在西部区域，部分实测界面的模拟效果并不理想。研究还针对埃及盖塔拉洼地与利比亚锡尔特盆地（Sirte basin）的水文演化过程开展了更为细致的探究。锡尔特盆地所呈现的演化特征差异，可能源于部分地质时期较高的蒸散发速率、前第四纪（pre-Quaternary）地层析出的盐类溶液，或是源自类萨布哈（sabkha）型现代含盐沉积物的咸水渗透作用。