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标题：Development and Verification of a Three‐Dimensional Variably Saturated Flow Model for Assessment of Future Global Water Resources
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作者：Yosuke Miura ; Kei Yoshimura
期刊名称：Journal of Advances in Modeling Earth Systems
电子版ISSN：1942-2466
出版年度：2020
卷号：12
期号：8
页码：1-14
DOI：10.1029/2020MS002093
出版社：John Wiley & Sons, Ltd.
摘要：Global water resource assessment has been conducted primarily for surface water and shallow groundwater (unconfined aquifers). Groundwater is a major water resource worldwide. Nevertheless, future water resource assessment integrating surface water and groundwater has not been carried out at the global scale. Large grid sizes are used in global‐scale models due to computer resource constraints. Underground, the unsaturated zone that connects surface water and groundwater is expressed using a vertically one‐dimensional grid of fixed size. However, the thickness of the unsaturated zone varies greatly between dry and humid areas, and future unsaturated zone conditions may differ from those at present due to climate change. In addition, for mountainous areas with steep slopes, representing the unsaturated zone in one vertical dimension is a major limitation. We believe that such a representation causes difficulty in adequately expressing underground water flow and thus introduces uncertainties into future prediction results. In this study, we developed a code to represent variably saturated flow with groundwater storativity in three dimensions based on physical equations, which can be used as references for parameterization in the future. To confirm the accuracy of this code, we verified it using vertical one‐ and two‐dimensional infiltration problems, a three‐dimensional groundwater pumping problem, hillslope problem, and water balance. The code achieved reliable results for each problem. Plain Language Abstract The state of future water resources at the global scale, taking into account climate change, remains highly uncertain. To date, water resource assessments have been conducted mainly on surface water. However, groundwater is one of the most important water resources and has not been included in water resource s assessments. This is largely due to the lack of a groundwater model that can be applied at the global scale. Therefore, we have developed a new groundwater model applicable at the global scale and verified its code. As a result, it was confirmed that the developed code provided a correct solution compared with experiments and other model results. In the future, we intend to use this code to conduct future water resource assessments, including assessments of groundwater. This is expected to produce outcomes that contribute to sustainable development.