Effect of soil property uncertainties on permafrost thaw projections: a calibration-constrained analysis: Modeling Archive

Modeling Archive Citation

D.R. Harp, A.L. Atchley, S.L. Painter, E.T. Coon, C.J. Wilson, V.E. Romanovsky, and J.C. Rowland. Effect of soil property uncertainties on permafrost thaw projections: a calibration-constrained analysis: Model Archive. 2016. Next Generation Ecosystem Experiments Arctic Data Collection, Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA. Data set accessed at http://dx.doi.org/10.5440/1236647 

Abstract

This Modeling Archive is in support of an NGEE Arctic publication available at doi:10.5194/tc-10-341-2016.

This dataset contains an ensemble of thermal-hydro soil parameters including porosity, thermal conductivity, thermal conductivity shape parameters, and residual saturation of peat and mineral soil. The ensemble was generated using a Null-Space Monte Carlo analysis of parameter uncertainty based on a calibration to soil temperatures collected at the Barrow Environmental Observatory site by the NGEE team. The micro-topography of ice wedge polygons present at the site is included in the analysis using three 1D column models to represent polygon center, rim and trough features. The Arctic Terrestrial Simulator (ATS) was used in the calibration to model multiphase thermal and hydrological processes in the subsurface.

Related NGEE Arctic Publication Citation

This Modeling Archive is provided in support of the following paper. Please cite this paper in addition to the modeling archive for full attribution of the modeling endeavour.

D.R. Harp, A.L. Atchley, S.L. Painter, E.T. Coon, C.J. Wilson, V.E. Romanovsky, and J.C. Rowland. 2016. Effect of soil property uncertainties on permafrost thaw projections: a calibration-constrained analysis. doi:10.5194/tc-10-341-2016

 

Modeling Archive Contents

Model:

Hydrothermal simulator: Arctic Terrestrial Simulator (ATS v0.83) (Contact: Ethan Coon; ecoon@lanl.gov)

Input Data:

Based on a calibration to soil temperatures collected at the Barrow Environmental Observatory site by the NGEE team

Parameters:

Coupled calibration results from Atchley et al (2015):

  1. PEST control file
  2. PEST par file

We used PEST command line utilities supcalc, randpar, and pnulpar to generate 20,000 null space parameter combinations choosing the smallest 5 eigenvalues to define the null space.

The results of the PEST super parameter analysis are:

PEST supcalc file

Out of the 20,000 null space parameter combinations, 1153 parameter combinations were within parameter bounds. The other parameter combinations were discarded.

Initializations:

 

These are all required files for running ATS. The xml is the ATS template run file used, the CESM8_5*h5 files contain atmospheric boundary conditions, and checkpoint05994.h5 contains the initial conditions:

CESM8_5ForcingV3.h5

CESM8_5-implicit.xml

CESM8_5Windspeed.h5

checkpoint05994.h5

 

Output: Configurations: Post Processing:

Model Analysis (Calibration and Null Space Monte Carlo): PEST

Model Analysis (Concurrent job execution): MATK

Results:

This script collects the 1153 parameter combinations into this MATK file and plots the following histograms (Figure 1) and paired plots (Figure 2).

This script performs postprocessing of 2013 calibration and 2014 evaluation results and plots the following time series for simulated and measured borehole temperatures for the 2013 calibration and the 2014 evaluation (Figure 3):

The following scripts are used to postprocess the Null Space Monte Carlo ATS simulations for further analysis and plotting:

      1. process_and_sort1D.py - This script processes ATS simulation visualization output into depth sorted variables. This script requires the parse_xmf Python module available in the utils directory of the ATS code repository.
      2. calc_alt.py - This script calls process_and_sort1D.py and calculates ALT and volume-averaged liquid saturation at the time of ALT.
      3. collect_depth_profiles.py - This script collects ATS simulation output variables for the entire column depth at the time of ALT for one year.
      4. stefan01.py - This script performs the numerical integration of the Stefan number (Equation 5) for one year.
      5. stefan_climate.py performs the same function as stefan01.py but operates on climate model output.

This script generates the following boxplots of permafrost metric projections (Figure 4).

This script plots time series of projected thaw depth and its 95% confidence band along with projected air temperuture and snow depth (Figure 5).

This script performs statistical analysis and plots depth profiles of ensemble ATS simulation results at the time of ALT (Figures 6 and Figure 7).

This script uses output generated by stefan01.py and stefan_climate.py to calculate soil property vs climate model uncertainty statistical analyses and plots the results (Figure 8).

This script performs ordinary least squares analyses of input parameters versus permafrost metrics and generates output for Table 2 and Figure 9, Figure 10, Figure 11, and Figure 12.

 

See associated csv file for ensemble of thermal-hydro soil parameters and the file data dictionary.