Effect of soil property uncertainties on permafrost thaw projections: a calibration-constrained analysis
The effects of soil property uncertainties on permafrost thaw projections are studied using a three-phase subsurface thermal hydrology model and calibration-constrained uncertainty analysis. The null-space Monte Carlo method is used to identify soil hydrothermal parameter combinations that are consi...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-02-01
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| Series: | The Cryosphere |
| Online Access: | http://www.the-cryosphere.net/10/341/2016/tc-10-341-2016.pdf |
| _version_ | 1818180054363930624 |
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| author | D. R. Harp A. L. Atchley S. L. Painter E. T. Coon C. J. Wilson V. E. Romanovsky J. C. Rowland |
| author_facet | D. R. Harp A. L. Atchley S. L. Painter E. T. Coon C. J. Wilson V. E. Romanovsky J. C. Rowland |
| author_sort | D. R. Harp |
| collection | DOAJ |
| description | The effects of soil property uncertainties on permafrost thaw projections are
studied using a three-phase subsurface thermal hydrology model and
calibration-constrained uncertainty analysis. The null-space Monte Carlo
method is used to identify soil hydrothermal parameter combinations that are
consistent with borehole temperature measurements at the study site, the
Barrow Environmental Observatory. Each parameter combination is then used in
a forward projection of permafrost conditions for the 21st century (from
calendar year 2006 to 2100) using atmospheric forcings from the Community
Earth System Model (CESM) in the Representative Concentration Pathway (RCP)
8.5 greenhouse gas concentration trajectory. A 100-year projection allows for
the evaluation of predictive uncertainty (due to soil property (parametric)
uncertainty) and the inter-annual climate variability due to year to year
differences in CESM climate forcings. After calibrating to measured borehole
temperature data at this well-characterized site, soil property uncertainties
are still significant and result in significant predictive uncertainties in
projected active layer thickness and annual thaw depth-duration even with a
specified future climate. Inter-annual climate variability in projected soil
moisture content and Stefan number are small. A volume- and time-integrated
Stefan number decreases significantly, indicating a shift in subsurface
energy utilization in the future climate (latent heat of phase change becomes
more important than heat conduction). Out of 10 soil parameters, ALT, annual
thaw depth-duration, and Stefan number are highly dependent on mineral soil
porosity, while annual mean liquid saturation of the active layer is highly
dependent on the mineral soil residual saturation and moderately dependent on
peat residual saturation. By comparing the ensemble statistics to the spread
of projected permafrost metrics using different climate models, we quantify
the relative magnitude of soil property uncertainty to another source of
permafrost uncertainty, structural climate model uncertainty. We show that
the effect of calibration-constrained uncertainty in soil properties,
although significant, is less than that produced by structural climate model
uncertainty for this location. |
| first_indexed | 2024-12-11T21:13:40Z |
| format | Article |
| id | doaj.art-c28c42b7b02d4480b2e20beba2716c06 |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2024-12-11T21:13:40Z |
| publishDate | 2016-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-c28c42b7b02d4480b2e20beba2716c062022-12-22T00:50:39ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242016-02-0110134135810.5194/tc-10-341-2016Effect of soil property uncertainties on permafrost thaw projections: a calibration-constrained analysisD. R. Harp0A. L. Atchley1S. L. Painter2E. T. Coon3C. J. Wilson4V. E. Romanovsky5J. C. Rowland6Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USAEarth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USAClimate Change Science Institute, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USAEarth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USAEarth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USAGeophysical Institute, University of Alaska Fairbanks, USAEarth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USAThe effects of soil property uncertainties on permafrost thaw projections are studied using a three-phase subsurface thermal hydrology model and calibration-constrained uncertainty analysis. The null-space Monte Carlo method is used to identify soil hydrothermal parameter combinations that are consistent with borehole temperature measurements at the study site, the Barrow Environmental Observatory. Each parameter combination is then used in a forward projection of permafrost conditions for the 21st century (from calendar year 2006 to 2100) using atmospheric forcings from the Community Earth System Model (CESM) in the Representative Concentration Pathway (RCP) 8.5 greenhouse gas concentration trajectory. A 100-year projection allows for the evaluation of predictive uncertainty (due to soil property (parametric) uncertainty) and the inter-annual climate variability due to year to year differences in CESM climate forcings. After calibrating to measured borehole temperature data at this well-characterized site, soil property uncertainties are still significant and result in significant predictive uncertainties in projected active layer thickness and annual thaw depth-duration even with a specified future climate. Inter-annual climate variability in projected soil moisture content and Stefan number are small. A volume- and time-integrated Stefan number decreases significantly, indicating a shift in subsurface energy utilization in the future climate (latent heat of phase change becomes more important than heat conduction). Out of 10 soil parameters, ALT, annual thaw depth-duration, and Stefan number are highly dependent on mineral soil porosity, while annual mean liquid saturation of the active layer is highly dependent on the mineral soil residual saturation and moderately dependent on peat residual saturation. By comparing the ensemble statistics to the spread of projected permafrost metrics using different climate models, we quantify the relative magnitude of soil property uncertainty to another source of permafrost uncertainty, structural climate model uncertainty. We show that the effect of calibration-constrained uncertainty in soil properties, although significant, is less than that produced by structural climate model uncertainty for this location.http://www.the-cryosphere.net/10/341/2016/tc-10-341-2016.pdf |
| spellingShingle | D. R. Harp A. L. Atchley S. L. Painter E. T. Coon C. J. Wilson V. E. Romanovsky J. C. Rowland Effect of soil property uncertainties on permafrost thaw projections: a calibration-constrained analysis The Cryosphere |
| title | Effect of soil property uncertainties on permafrost thaw projections: a calibration-constrained analysis |
| title_full | Effect of soil property uncertainties on permafrost thaw projections: a calibration-constrained analysis |
| title_fullStr | Effect of soil property uncertainties on permafrost thaw projections: a calibration-constrained analysis |
| title_full_unstemmed | Effect of soil property uncertainties on permafrost thaw projections: a calibration-constrained analysis |
| title_short | Effect of soil property uncertainties on permafrost thaw projections: a calibration-constrained analysis |
| title_sort | effect of soil property uncertainties on permafrost thaw projections a calibration constrained analysis |
| url | http://www.the-cryosphere.net/10/341/2016/tc-10-341-2016.pdf |
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