Investigating Arctic Climate Variability with Global Sensitivity Analysis of Low-resolution E3SM.

 As a first step in quantifying uncertainties in simulated Arctic climate response, Sandia researchers have performed a global sensitivity analysis (GSA) using a fully coupled ultralow-resolution configuration of the Energy Exascale Earth System Model (E3SM).  Coupled Earth system models are computationally expensive to run, making it difficult to generate the large ensembles required for uncertainty quantification.  In this research an ultralow version of E3SM was utilized to tractably investigate parametric uncertainty in the fully coupled model. More than one hundred perturbed simulation ensembles of one hundred years each were generated for the analysis and impacts on twelve Arctic quantities of interest were measured using the PyApprox library. The parameter variations show significant impact on the Arctic climate state with the largest impact coming from atmospheric parameters related to cloud parameterizations. To our knowledge, this is the first global sensitivity analysis involving the fully-coupled E3SM. The results will be used to inform model tuning work as well as targeted studies at higher resolution.

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Ultra-low atmosphere grid (left) and ultra-low ocean grid (right).
Ultra-low atmosphere grid (left) and ultra-low ocean grid (right).



Kara J. Peterson,
Irina Tezaur,

January 1, 2021