Time: 15:30-16:30, 7th December 2017
Venue: Lecture Hall (221), Building No.16,Weijin Campus, Tianjin University
Speaker: Prof. WANG Tiejun, Institute of Surface-Earth System Science, Tianjin University
Topic: Spatiotemporal patterns of water table fluctuations and evapotranspiration induced by riparian vegetation
Abstract: Groundwater evapotranspiration (ETg) is an important component in regional water budgets. In this study, an extensive monitoring network was established in a semiarid riparian area to investigate various controls on the spatiotemporal pattern of water table fluctuations (WTFs) and ETg induced by riparian vegetation. Along a vegetation gradient (~1200 m), diurnal WTFs were observed during a growing season in areas covered by woody species and wet slough vegetation with deeper root systems; whereas, no diurnal WTFs were found in the middle section with shallower-rooted grasses. The occurrence of diurnal WTFs was related to temperature-controlled plant phenology at seasonal scales and to radiation at subdaily scales. Daily ETg in the mid-growing season was calculated using the White method. The results revealed that depth to water table (DTWT) was the dominant control on ETg, followed by potential evapotranspiration (ETp). Finally, exponential relationships between ETg/ETp and DTWT were obtained at the study site, although those relationships varied considerably across the sites. This study demonstrates the complex interactions of WTFs and ETg with surrounding environmental variables and provides further insight into modeling ETg over different time scales and riparian vegetation.
