DART-PFLOTRAN: An Ensemble Data Assimilation System for Modeling Subsurface Process
Abstract
Following a Monte Carlo approach, Ensemble Data Assimilation (EDA) has proven to be effective in inverse modelling of subsurface process. However, developing an EDA application can be complicated due to factors such as physical model input/output processing, data assimilation configuration, observation subsetting (for sequential assimilation), etc. Here, we develop a generic software framework for seamlessly conducting EDA on subsurface dynamics simulation. The framework leverages the Data Assimilation Research Testbed (DART) as the core assimilation engine, and integrates it with a massively Parallel subsurface FLOw and TRANsport model (PFLOTRAN), called DART-PFLOTRAN. By enabling smoother in DART, DART-PFLOTRAN adopts a sequential Ensemble Smoother for Multiple Data Assimilation (ES-MDA) workflow, encompassing cases for both smoother and filter. We applied the developed framework in two case studies using a one-dimensional groundwater model which generates synthetic belowground temperature dynamics. The first study verifies the capability of ES-MDA in DART-PFLOTRAN by estimating the permeability through assimilating the synthetic temperature observations. Meanwhile, in the second study, we tested the performance of sequential ES-MDA by estimating the dynamic groundwater flow flux with temperature assimilated sequentially in multiple time windows. Both studies provide reliable estimation of the permeability and the groundwater flow flux, show the applicability of DART-PFLOTRAN in iterative EDA (either sequentially or not). Upon the success of the synthetic studies, we then employed DART-PFLOTRAN to estimate a three-dimensional heterogeneous permeability field at the 300 area of Hanford site, by assimilating water level observations at multiple groundwater wells. These successful applications show that the software framework would pave the way for future large-scale subsurface inverse modelling, which potentially involves subsetting numerous observations.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMH103...03J
- Keywords:
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- 1804 Catchment;
- HYDROLOGY;
- 1830 Groundwater/surface water interaction;
- HYDROLOGY;
- 1849 Numerical approximations and analysis;
- HYDROLOGY;
- 1879 Watershed;
- HYDROLOGY