Abstract

Sea level rise (SLR) is one of the prime consequences of global warming as pointed out by the Intergovernmental Panel on Climate Change (IPCC). SLR adversely affects coastal regions; triggers coastal erosion, inundation, and affects the freshwater–seawater interface as well. This paper presents the results of a study in which a coastal aquifer under changing climate was simulated using a three-dimensional groundwater model. The study area covers a part of the coastal aquifer in Ernakulam district in the State of Kerala, India. Support Vector Machine (SVM) was used for projection of future sea levels under the representative concentration pathways (RCPs) 4.5 and 8.5, based on the projections of Phase 5 of the Coupled Model Intercomparison Project (CMIP5). Both thermosteric and halosteric components were taken into account in the projection of sea level. It was observed that sea level changes are significantly influenced by the halosteric effect. Results indicate that SLR in the year 2050 with respect to the levels in 2014 will be about 8.64 cm and 12.96 cm under RCPs 4.5 and 8.5, respectively. The repercussions of this rise in sea level on seawater intrusion into the coastal aquifer were evaluated by performing simulations with SEAWAT. Results of the study indicate that the effect of this SLR on seawater intrusion is negligible.

Highlights

• The impact of projected climate change on seawater intrusion in a densely populated coastal region was assessed using a variable density model

• Local climatic variables influencing sea level were identified

• Machine learning approach was employed for statistical downscaling of sea level using climatic variables

• Both thermosteric and halosteric effects were taken in to account in the projection of sea level rise

中文翻译：

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预计的气候变化对区域沿海含水层海水入侵的影响

摘要

政府间气候变化专门委员会（IPCC）指出，海平面上升（SLR）是全球变暖的主要后果之一。SLR对沿海地区产生不利影响；引发海岸侵蚀，淹没，并影响淡水与海水的界面。本文介绍了一项研究结果，其中使用三维地下水模型模拟了气候变化下的沿海含水层。研究区域覆盖了印度喀拉拉邦Ernakulam区的一部分含水层。基于耦合模型比较项目（CMIP5）的第5阶段的预测，使用支持向量机（SVM）来预测具有代表性的集中路径（RCP）4.5和8.5下的未来海平面。在海平面的投影中，考虑了热固性和卤代性成分。观察到，海平面变化受屈光效应的影响很大。结果表明，相对于2014年的水平，2050年的SLR在RCP 4.5和8.5下分别约为8.64 cm和12.96 cm。通过使用SEAWAT进行模拟，评估了海平面上升对海水入侵沿海含水层的影响。研究结果表明，这种单反对海水入侵的影响可以忽略不计。通过使用SEAWAT进行模拟，评估了海平面上升对海水入侵沿海含水层的影响。研究结果表明，这种单反对海水入侵的影响可以忽略不计。通过使用SEAWAT进行模拟，评估了海平面上升对海水入侵沿海含水层的影响。研究结果表明，这种单反对海水入侵的影响可以忽略不计。

强调

• 使用可变密度模型评估了预计的气候变化对人口密集的沿海地区海水入侵的影响

• 确定影响海平面的当地气候变量

• 使用机器学习方法利用气候变量对海平面进行统计缩减

• 考虑到了海平面上升的预测，同时考虑了热力和恒力作用