Climate Systems Interaction Group

Surface Temperature Probability Distributions in the NARCCAP Hindcast Experiment: Evaluation Methodology, Metrics and Results.

Paul C. Loikith, Duane E. Waliser, Huikyo Lee, Jinwon Kim, J. David Neelin, Benjamin R. Lintner, Seth McGinnis, Chris A. Mattmann, Linda O. Mearns

J. Clim., 28, 978-997, doi:10.1175/JCLI-D-13-00457.1. Paper 7.1 MB.

Abstract Methodology is developed and applied to evaluate the characteristics of daily surface temperature probability distribution functions (PDFs) in a six-member regional climate model (RCM) hindcast experiment conducted as part of the North American Regional Climate Change Assessment Program (NARCCAP). The evaluation is based on two state-of-the-art high-resolution reanalysis products that provide the observational reference(s): the NCEP North American Regional Reanalysis and the NASA Modern Era-Retrospective Analysis for Research and Applications. Typically, the NARCCAP temperature biases for the tails and the medians of the PDFs are of the same sign, indicating a shift in the RCM-simulated PDFs relative to reanalysis. RCM-simulated temperature variance is often higher than reanalysis in both winter and summer. Temperature skewness is reasonably well simulated by most RCMs, especially in the winter, suggesting confidence in the use of these models to simulate future temperature extremes. To facilitate identification of model-reanalysis discrepancies and provide a regional basis for investigating mechanisms associated with such discrepancies, a k-means clustering approach is applied to sort model and reference data PDFs by PDF morphology. RCM cluster assignments generally match reanalysis cluster assignments with some discrepancy at high latitudes due to over-simulation of temperature variance by most models here. Model biases identified in this work will allow for further investigation into associated mechanisms and implications for future simulations of temperature extremes.

Citation Loikith, P. C., J. Kim, H. Lee, B. R. Lintner, C. Mattmann, J. D. Neelin, D. E. Waliser, L. Mearns and S. McGinnis: Evaluation of Surface Temperature Probability Distribution Functions in the NARCCAP Hindcast Experiment. J. Clim., 28, 978-997, doi:10.1175/JCLI-D-13-00457.1.

Acknowledgments. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Part of this research was funded by NASA National Climate Assessment 11-NCA11-0028 and AIST AIST-QRS-12-0002 projects and the NSF ExArch 1125798 (P.C.L., J.K., H.L., D.E.W., C.M.). Part of this research was funded by NOAA NA11OAR4310099 (J.D.N.).

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