Feasibility of Improving Groundwater Modeling by Assimilating Evapotranspiration Rates. Issue 2 (1st March 2020)

• Record Type: Journal Article
• Authors: Gelsinari, Simone; Doble, Rebecca; Daly, Edoardo; Pauwels, Valentijn R. N.
• Is Part Of: Water resources research. Volume 56:Issue 2(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-03-01
• Subjects: groundwater -- data assimilation -- ensemble Kalman filter -- unsaturated zone -- evapotranspiration -- MODFLOW; Hydrology -- Periodicals; 333.91
• DOI: 10.1029/2019WR025983
• Languages: English
• ISSNs: 0043-1397

Abstract

Abstract: Water table dynamics are linked to the atmosphere through evapotranspiration and recharge. The assimilation of observed evapotranspiration values should thus improve groundwater model results. This paper presents a method for assimilating evapotranspiration data into a coupled unsaturated zone and groundwater model using the ensemble Kalman filter. The method is tested for a synthetically generated losing stream system in climatic conditions common in South Australia. The study focused on areas with a deep (recharge area) and a shallow (extraction area) water table and an intermediate area showing seasonal variations between these two (transition area). The data assimilation algorithm consistently improved the model states in the three areas when the ensemble spread was adequate. Improvements were also obtained in the calculation of net recharge and modeled actual evapotranspiration. The results indicate the potential to improve groundwater models using remote sensing observations of actual evapotranspiration values. Key Points: The assimilation of actual evapotranspiration into a coupled unsaturated‐groundwater model is presented using the ensemble Kalman filter A simple unsaturated zone model was developed to link groundwater tables to land surface accounting for groundwater‐vegetation interaction The method, tested in a synthetically generated experiment, improves model states leading to improved net recharge and evapotranspiration