edu.ucar.opensky::technotes:575 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-25T15:42:44.306927 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7sn0czx A Statistical Investigation of the CESM Ensemble Consistency Testing Framework 2018-12-27T00:00:00Z publication https://n2t.org/ark:/85065/d7sn0czx https://doi.org/10.26024/bfdr-nz31 Molinari, Stephen author Milroy, Daniel author Hammerling, Dorit author UCAR/NCAR - Library publisher Constant evolution and improvement of large scale climate simulation codes such as the Community Earth System Model (CESM) necessitate quality checks to verify the constitution of new climate simulations. The CESM Ensemble Consistency Test (CESM-ECT) was developed as a flexible but objective method for checking the statistical consistency between an accepted ensemble of climate simulations and a new simulation created with updated code or within a new computational infrastructure. CESM-ECT utilizes a testing framework based on the popular technique of Principal Component Analysis (PCA) to determine whether a set of new simulations is statistically distinguishable from the established ensemble of climate simulations. One shortcoming of PCA is that accurate estimation requires the computational expense of a large ensemble. In this work we begin with an exploratory analysis of the CESM climate simulation data as well as an overview of PCA. Then we develop certain diagnostic tools to evaluate the estimation within PCA with respect to the size of the ensemble. Finally we demonstrate the limitations of PCA for smaller ensemble sizes by showing poor performance according to our diagnostics as well as an increased false positive rate for both empirical and simulated data. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Coupled climate models Statistical applications theme U.S. National Aeronautics and Space Administration Global Change Master Directory GCMD 2021-09-17 revision 11.2 NASA Global Change Master Directory originator Valids List: Science and Services Keywords Copyright Author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. None eng geoscientificInformation