Data assimilation of satellite-based terrestrial water storage changes into a hydrology land-surface model

JOURNAL OF HYDROLOGY

卷:597

Article

Bahrami, Ala¹  Goita, Kalifa¹  Magagi, Ramata¹  Davison, Bruce²  Razavi, Saman³  Elshamy, Mohamed³  Princz, Daniel² 

[1] Univ Sherbrooke, Ctr Applicat & Rech Teledetect CARTEL, Dept Geomat Appl, Sherbrooke, PQ, Canada

[2] Environm & Climate Change Canada, Saskatoon, SK, Canada

[3] Global Inst Water Secur, Sch Environm & Sustainabil, Saskatoon, SK, Canada

关键词: GRACE;    MESH;    Data assimilation;    EnKS;    Snow water equivalent;    Terrestrial water storage;   

DOI  :  10.1016/j.jhydrol.2020.125744

来源: Elsevier

【 摘 要 】

Accurate estimation of snow mass or snow water equivalent (SWE) over space and time is required for global and regional predictions of the effects of climate change. This work investigates whether integration of remotely sensed terrestrial water storage (TWS) information, which is derived from the Gravity Recovery and Climate Experiment (GRACE), can improve SWE and streamflow simulations within a semi-distributed hydrology land surface model. A data assimilation (DA) framework was developed to combine TWS observations with the MESH (Modelisation Environnementale Communautaire - Surface Hydrology) model using an ensemble Kalman smoother (EnKS). The snow-dominated Liard Basin was selected as a case study. The proposed assimilation methodology reduced bias of monthly SWE simulations at the basin scale by 17.5% and improved unbiased root-mean-square difference (ubRMSD) by 23%. At the grid scale, the DA method improved ubRMSD values and correlation coefficients for 85% and 97% of the grid cells, respectively. Effects of GRACE DA on streamflow simulations were evaluated against observations from three river gauges, where it effectively improved the simulation of high flows during snowmelt season from April to June. The influence of GRACE DA on the total flow volume and low flows was found to be variable. In general, the use of GRACE observations in the assimilation framework not only improved the simulation of SWE, but also effectively influenced streamflow simulations.

【 授权许可】

Free