Global‐scale land surface hydrologic modeling with the representation of water table dynamics

摘要: [1] Water table dynamics, a basic hydrologic process, was traditionally not considered in global-scale land surface models (LSMs). In this study, representation of water dynamics is integrated into global LSM to address the shortcomings existing modeling studies and appropriateness specifying certain parameters as globally constant. Evaluation model simulation using varying against river discharge observations selected large rivers shows improvements when included model. The mechanisms by which affects are then investigated analyzing sensitivity groundwater (GW) capillary flux. result indicates that mean evapotranspiration (ET) increases ~9% GW flux considered. semiarid regions with marked dry season have largest increase (~25%), while humid high-latitude sufficient moisture but limited radiation energy smallest increase. Increase ET more pronounced recharge becomes negative (upward supply from aquifer), its magnitude depends on depth (WTD). On other hand, deeper WTD caused found decrease runoff throughout year only. Based our result, about 50% area (especially regions) simulated shallower than 5 m, emphasizes significance representing LSMs.