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

Abstract

The interaction between surface water and groundwater is an important aspect of hydrological processes. Despite its importance, groundwater is not well represented in many land surface models. In this study, a groundwater module with consideration of surface water and groundwater dynamic interactions is incorporated into the distributed biosphere hydrological (DBH) model in the upstream of the Yellow River basin, China. Two numerical experiments are conducted using the DBH model: one with groundwater module active, namely, DBH_GW and the other without, namely, DBH_NGW. Simulations by two experiments are compared with observed river discharge and terrestrial water storage (TWS) variation from the Gravity Recovery and Climate Experiment (GRACE). The results show that river discharge during the low flow season that is underestimated in the DBH_NGW has been improved by incorporating the groundwater scheme. As for the TWS, simulation in DBH_GW shows better agreement with GRACE data in terms of interannual and intraseasonal variations and annual changing trend. Furthermore, compared with DBH_GW, TWS simulated in DBH_NGW shows smaller decreases during autumn and smaller increases in spring.These results suggest that consideration of groundwater dynamics enables a more reasonable representation of TWS change by increasing TWS amplitudes and signals and as a consequence, improves river discharge simulation in the low flow seasons when groundwater is a major component in runoff. Additionally, incorporation of groundwater module also leads to wetter soil moisture and higher evapotranspiration, especially in the wet seasons.

Towards the representation of groundwater in the Joint UK Land Environment Simulator

“…Note that our approach is different from other previous studies. For instance, the developed approach by Niu et al (2007) and Huang et al (2019) extracts the baseflow from the aquifer, as a percentage of the storage or the water table depth using an exponential function. In our study, the flux of baseflow comes from the contribution of aquifer to the soil domain by an additional upward flux component.…”

“…There are two main classifications of groundwater coupling, namely, the empirical lumped GW models and the physically based distributed GW models (Tian et al, 2012). Regarding their dimension, this can be either a one‐dimensional (1‐D) model (e.g., Gedney & Cox, 2003; Maxwell & Miller, 2005; Yeh and Eltahir, 2005a; Niu et al, 2007; Huang et al, 2019), two‐dimensional (2‐D) model (e.g., Fan & Miguez‐Macho, 2011; Vergnes & Decharme, 2012) or 3‐D model (e.g., Gutowski Jr et al, 2002; Maxwell et al, 2011; Tian et al, 2012; York et al, 2002). In the 1‐D coupling, the soil domain is extrapolated for a few tens of meters.…”

Large‐Scale Assessment of Delayed Groundwater Responses to Drought

“…The groundwater model developed for this study can correctly capture these characteristic differences of groundwater and baseflow. Similarly, Huang et al (2019) showed that the use of a groundwater layer in a hydrological model can improve simulated surface discharge, particularly during low flows when baseflow contribution is high. A large-scale model including lateral flows offers the opportunity to disentangle both the diversity of groundwater responses and the differences of groundwater head and baseflow fluctuations, that is, the difference of groundwater drought and the groundwater's role in drought propagation.…”

Streamflow change on the Qinghai-Tibet Plateau and its impacts

“…冰川融水径流除了对下游河流、湖泊等水体径流 和水位产生影响之外, 也可能增加土壤含水量、补给 壤中流等影响地表产流过程, 从而改变下游河道径流, 这一影响过程往往更具有长期性 [67] . 黄河源区径流受 冰川融水影响较大, 但汛期则以降水为主, 因此源区出 口(唐乃亥站)汛期径流减少与源区降水减少导致的径 流变化有较大关系 [68] ; 枯季地下水是径流的重要补给 来源, 枯季径流的年际变化可能与冰雪融水有较大关 系 [69] . 雅鲁藏布江从上游到下游受地下水补给和融水 补给的比例逐渐增大, 近年来在全球变暖导致冰川退 缩加剧的背景下, 上游融水径流变化对下游的影响可 能更为显著和深刻 [67] .…”