Coupling a groundwater model with a land surface model to improve water and energy cycle simulation

Abstract

The water and energy cycles interact, making them generally closely related. Land surface models (LSMs) can describe the water and energy cycles of the land surface, but their description of the subsurface water processes is oversimplified, and lateral groundwater flow is ignored. Groundwater models (GWMs) well describe the dynamic movement of subsurface water flow, but they cannot depict the physical mechanism of the evapotranspiration (ET) process in detail. In this study, a coupled model of groundwater with simple biosphere (GWSiB) is developed based on the full coupling of a typical land surface model (SiB2) and a three-dimensional variably saturated groundwater model (AquiferFlow). In this model, the infiltration, ET and energy transfer are simulated by SiB2 via the soil moisture results given by the groundwater flow model. The infiltration and ET results are applied iteratively to drive the groundwater flow model. The developed model is then applied to study water cycle processes in the middle reaches of the Heihe River Basin in the northwest of China. The model is validated through data collected at three stations in the study area. The stations are located in a shallow groundwater depth zone, a deeper groundwater depth zone and an agricultural irrigation area. The study results show that the coupled model can well depict the land surface and groundwater interaction and can more comprehensively and accurately simulate the water and energy cycles compared with uncoupled models

The influence of groundwater representation on hydrological simulation and its assessment using satellite‐based water storage variation

“…Intermediate zone and groundwater aquifer constitute a complex system, which is poorly represented by the simple one‐layer groundwater scheme in the DBH model. In fact, groundwater stores in unconfined aquifer, which can be presented by multiple layers, and physically based distributed dynamic groundwater model can well represent the groundwater flows (Niu, Yang, Dickinson, Gulden, & Su, ; Tian, Li, Cheng, Wang, & Hu, ; Wendland, Rabelo, & Roehrig, ), and deep soil also plays an important role in hydrological processes (Le Vine et al, ). Water stores in the intermediate zone between unsaturated soil and groundwater is of great significance in TWS variation (Rodell & Famiglietti, ), and without consideration of intermediate zone could result in underestimation of TWS.…”

“…Furthermore, the interaction between confined aquifer and surface water is considerable, and water storing in confined aquifer has been proved to be a great part of total TWS (de Graaf et al, ). Only vertical water exchanges between groundwater and surface water are considered in this study, but neglecting subgrid groundwater flow and lateral flow in soil, which has significant impacts on hydrological processes (Tian et al, ). Furthermore, groundwater depth in DBH model is converted by the groundwater storage variation, whereas a physical mechanism‐based water table parameterization is still lack, which could have a direct impact on the simulated water table and then affect baseflow simulation.…”

Groundwater in the Earth's critical zone: Relevance to large‐scale patterns and processes

“…If the above arguments continue to hold true as more cross‐scale syntheses are brought into light in the future, then efforts are needed to tap the collective wisdom of the critical zone science community who have developed a rich set of data and theories at the smaller scales, for the purpose of representing the most essential groundwater processes in Earth System Models. The last decade or so has seen a surge of interests and efforts in including groundwater processes in ESM development and applications [e.g., Liang et al ., ; Maxwell and Miller , ; Yeh and Eltahir , ; Niu et al ., ; Maxwell and Kollet , ; Yuan et al ., ; Zeng and Decker , ; Jiang et al ., ; Ferguson and Maxwell , ; Lo and Famiglietti , ; Choi and Liang , ; Leung et al ., ; Yuan and Liang , ; Lam et al ., ; Vergnes et al ., ; Zampieri et al ., ; Tian et al ., ; Xie et al ., ; Shen et al ., ; Decker et al ., ; Krakauer et al ., ; Cai et al ., ; Leng et al ., ; Sutanudjaja et al ., ; Koirala et al ., ]. However, the choice of processes, the approaches to represent multiscale structures and heterogeneities, the data and computation demands, etc., all vary greatly among the research groups even working on the same land models.…”

Evaluation of drought propagation in an ensemble mean of large-scale hydrological models

“…First steps on the improvement of storage simulation are being set by Sutanudjaja et al (2011) and Tian et al (2012), who coupled a groundwater model (MODFLOW and AquiferFlow) to a land surface model (PCR-GLOBWB and SiB2). An important limitation is that these couplings are still offline, not allowing for dynamic feedbacks between groundwater storage, soil moisture, and evapotranspiration (Sutanudjaja et al, 2011).…”