Efficient Screening of Climate Model Sensitivity to a Large Number of Perturbed Input Parameters [plus supporting information]
Modern climate models contain numerous input parameters, each with a range of possible values. Since the volume of parameter space increases exponentially with the number of parameters N, it is generally impossible to directly evaluate a model throughout this space even if just 23 values are chosen for each parameter. Sensitivity screening algorithms, however, can identify input parameters having relatively little effect on a variety of output fields, either individually or in nonlinear combination.This can aid both model development and the uncertainty quantification (UQ) process. Here we report results from a parameter sensitivity screening algorithm hitherto untested in climate modeling, the Morris oneatatime (MOAT) method. This algorithm drastically reduces the computational cost of estimating sensitivities in a high dimensional parameter space because the sample size grows linearly rather than exponentially with N. It nevertheless samples over much of the Ndimensional volume and allows assessment of parameter interactions, unlike traditional elementary oneatatime (EOAT) parameter variation. We applied both EOAT and MOAT to the Community Atmosphere Model (CAM), assessing CAM’s behavior as a function of 27 uncertain input parameters related to the boundary layer, clouds, and other subgrid scale processes. For radiation balance at the top of the atmosphere, EOAT and MOATmore »
 Authors:

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 Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
 Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Univ. of California, Berkeley, CA (United States). Dept. of Astronomy
 Publication Date:
 Report Number(s):
 LLNLJRNL626954
Journal ID: ISSN 19422466
 Grant/Contract Number:
 AC5207NA27344
 Type:
 Accepted Manuscript
 Journal Name:
 Journal of Advances in Modeling Earth Systems
 Additional Journal Information:
 Journal Volume: 5; Journal Issue: 3; Journal ID: ISSN 19422466
 Publisher:
 American Geophysical Union (AGU)
 Research Org:
 Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
 Sponsoring Org:
 USDOE
 Country of Publication:
 United States
 Language:
 English
 Subject:
 54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES; 97 MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
 OSTI Identifier:
 1240071
Covey, Curt, Lucas, Donald D., Tannahill, John, Garaizar, Xabier, and Klein, Richard. Efficient Screening of Climate Model Sensitivity to a Large Number of Perturbed Input Parameters [plus supporting information]. United States: N. p.,
Web. doi:10.1002/jame.20040.
Covey, Curt, Lucas, Donald D., Tannahill, John, Garaizar, Xabier, & Klein, Richard. Efficient Screening of Climate Model Sensitivity to a Large Number of Perturbed Input Parameters [plus supporting information]. United States. doi:10.1002/jame.20040.
Covey, Curt, Lucas, Donald D., Tannahill, John, Garaizar, Xabier, and Klein, Richard. 2013.
"Efficient Screening of Climate Model Sensitivity to a Large Number of Perturbed Input Parameters [plus supporting information]". United States.
doi:10.1002/jame.20040. https://www.osti.gov/servlets/purl/1240071.
@article{osti_1240071,
title = {Efficient Screening of Climate Model Sensitivity to a Large Number of Perturbed Input Parameters [plus supporting information]},
author = {Covey, Curt and Lucas, Donald D. and Tannahill, John and Garaizar, Xabier and Klein, Richard},
abstractNote = {Modern climate models contain numerous input parameters, each with a range of possible values. Since the volume of parameter space increases exponentially with the number of parameters N, it is generally impossible to directly evaluate a model throughout this space even if just 23 values are chosen for each parameter. Sensitivity screening algorithms, however, can identify input parameters having relatively little effect on a variety of output fields, either individually or in nonlinear combination.This can aid both model development and the uncertainty quantification (UQ) process. Here we report results from a parameter sensitivity screening algorithm hitherto untested in climate modeling, the Morris oneatatime (MOAT) method. This algorithm drastically reduces the computational cost of estimating sensitivities in a high dimensional parameter space because the sample size grows linearly rather than exponentially with N. It nevertheless samples over much of the Ndimensional volume and allows assessment of parameter interactions, unlike traditional elementary oneatatime (EOAT) parameter variation. We applied both EOAT and MOAT to the Community Atmosphere Model (CAM), assessing CAM’s behavior as a function of 27 uncertain input parameters related to the boundary layer, clouds, and other subgrid scale processes. For radiation balance at the top of the atmosphere, EOAT and MOAT rank most input parameters similarly, but MOAT identifies a sensitivity that EOAT underplays for two convection parameters that operate nonlinearly in the model. MOAT’s ranking of input parameters is robust to modest algorithmic variations, and it is qualitatively consistent with model development experience. Supporting information is also provided at the end of the full text of the article.},
doi = {10.1002/jame.20040},
journal = {Journal of Advances in Modeling Earth Systems},
number = 3,
volume = 5,
place = {United States},
year = {2013},
month = {7}
}