Inverse Modeling & Data Assimilation

I am interested in scalable inversion methods that incoporate multi-physics model and various types of data with different information content.

For example, different types of data with coupled physics models can improve subsurface characterization as below:

K simulation

(a) True K (left) and tracer test (right); (b) Estimated K and corresponding simulation using only head data; (c) Estimated K and corresponding simulation using both head and tracer data
• True log-permeability (K) field (fig. a) was used to generate steady state pressure (o in fig.b) and transient concentration (+ in fig. c) from tracer injection at (x,y) = (10 m, 10 m).
• Principal Component Geostatistical Approach (PCGA) [Lee and Kitanidis, 2014] was used to estimate K fields using only pressure data (fig. b) and both pressure and tracer travel-time data (fig.c).
• USGS MODFLOW (flow) and MT3DMS (transport) were linked with PCGA as black box simulators with only a few hundred runs in total.

Large-Scale and Big Enviromental Data Inversion and Uncertainty Quantification

  • Sand box characterization using a huge tracer data set obtained from MRI [Lee et al., WRR 2016]

  • Reactive mineral imaging [Fakreddine et al., AWR 2016]

  • Saline Aquifer Characterization using Density-driven flow and transport modeling [Kang et al., in review]

  • Joint inversion using pressure and heat tracer [Lee et al., in review]

  • Data-worth analysis for reliable prediction of DNAPL fate

Efficient Real-Time Data Assimilation for Near-shore Bathymetry Identification

ERDC-CHL

Nano-scale Carbonate Rock Reconstruction

  • Nano-scale FIB-SEM image processing and multi-point geostatistics

Software Developments

Below are the list of software that will be released soon..

  • H-matrices based randomized SVD

  • PCGA

  • Scalable geostatistics simulator