Canadian Centre for Climate Modelling and Analysis Modeling Group Country Canada Météo-France / Centre National de Recherches Météorologiques France Commonwealth Scientific and Industrial Research Organization in collaboration with Queensland Climate Change Centre of Excellence Geophysical Fluid Dynamics Laboratory Goddard Institute for Space Studies USA Max Planck Institute for Meteorology Meteorological Research Institute Germany Japan Spatial Resolution (lon x lat) 3.75° x 3.75° 2.81° x 2.81° 2.81° x 2.81° Model Name CCCMA-CGCM3.1(T47) CCCMA-CGCM3.1(T63) CNRM-CM 3 ID C1 C2 D Australia CSIRO-Mk3.0 CSIRO-Mk3.5 S1 S2 1.88° x 1.88° * 1.88° x 1.88° * USA GFDL-CM2.0 GFDL-CM2.1 GISS-AOM GISS-EH GISS-ER MPI-ECHAM5 MRI-CGCM2.3.2 G1 G2 E1 E2 E3 P R 2.50° x 2.00° * 2.50° x 2.00° * 4.00° x 3.00° 5.00° x 3.91° 5.00° x 3.91° 1.88° x 1.88° * 2.81° x 2.81° Table 1. List of the CMIP3 models used for the evaluation of 20th century heavy precipitation and its associated physical mechanisms in this paper. The approximate spatial resolutions were calculated by dividing 360° or 180° by the number of grid cells in the longitude or latitude dimensions, respectively. Asterisks next to spatial resolution denote climate models whose grids were transformed to the common 2.5°x2.5° resolution using area averaging. All others were transformed using linear interpolation. Ensemble member run # 1 was used for all models except for the GFDL-CM2.1 and GISS-EH, in which run # 2 and # 5 were used, respectively. Models were assigned letters (ID column) for ease of reference in analyses showing results from individual models. [Further documentation for individual models, including expansions of all acronyms, is available online at http://wwwpcmdi.llnl.gov/ipcc/model_documentation/ipcc_model_documentation.php.] Modeling Group Beijing Climate Center, China Meteorological Administration Canadian Centre for Climate Modelling and Analysis Centre National de Recherches Meteorologiques / Centre Europeen de Recherche et Formation Avancees en Calcul Scientifique Commonwealth Scientific and Industrial Research Organization in collaboration with Queensland Climate Change Centre of Excellence LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences NOAA Geophysical Fluid Dynamics Laboratory Spatial Resolution (lon x lat) 2.81° x 2.81° 2.81° x 2.81° 1.41° x 1.41° * Country China Canada France Model Name BCC-CSM1.1 CanESM2 CNRM-CM5 ID B C D Australia CSIRO-Mk3.6.0 S 1.88° x 1.88° * China USA FGOALS-s2 GFDL-ESM2G GFDL-ESM2M HadGEM2-CC INM-CM4 IPSL-CM5A-LR IPSL-CM5A-MR MIROC-ESM MIROC-ESM-CHEM F G1 G2 H I L1 L2 M1 M2 2.81° x 1.67° * 2.50° x 2.00° * 2.50° x 2.00° * 1.88° x 1.25° * 2.00° x 1.50° * 3.75° x 1.88° 2.50° x 1.26° * 2.81° x 2.81° 2.81° x 2.81° Japan MIROC5 M3 1.41° x 1.41° * Germany MPI-ESM-LR MPI-ESM-MR MRI-CGCM3 P1 P2 R 1.88° x 1.88° * 1.88° x 1.88° * 1.13° x 1.13° * Met Office Hadley Centre Institute for Numerical Mathematics Institut Pierre-Simon Laplace UK Russia France Japan Agency for Marine-Earth Science and Technology, Atmosphere and Ocean Research Institute (The University of Tokyo), and National Institute for Environmental Studies Atmosphere and Ocean Research Institute (The University of Tokyo), National Institute for Environmental Studies, and Japan Agency for Marine-Earth Science and Technology Max Planck Institute for Meteorology Japan Meteorological Research Institute Japan Table 2. As in Table 1 but for the CMIP5 models used for analysis in this paper. Ensemble member run # 1 was used for all models. Figure 1. The mean annual precipitation falling from the 99th percentile and above (P99M) during the period 1979-99 for (a) the CPC observations and the difference between the multi-model average and CPC for (b) CMIP3 and (c) CMIP5. Figure 2. Scatterplots of RMS error in P99M over North America versus horizontal resolution of CMIP models for (a) annual, (b) winter, and (c) summer daily data when compared with CPC observations. The abscissa is plotted on a log scale due to the wide range in spatial resolution between the models. Letters identify the individual models, as defined in Tables 1-2, where red letters correspond to CMIP3 and blue letters correspond to CMIP5. “A” represents the multi-model average, where the RMS error is computed after first computing the multi-model average biases at every grid cell. A least squares linear fit to the RMS error versus log(resolution) values for each model subset and for all the models together is plotted, along with the corresponding correlation coefficients (R2). Figure 3. Composites of pressure at mean sea level (PRMSL, hPa, contours) and 500 mb geopotential height standardized anomalies (Z500*, dimensionless, color fills) for the top 1% of daily annual precipitation events at selected grid cells (indicated by black rectangles, which vary from top to bottom). Sea level pressure is contoured every 2 hPa. Composites for NARR, the CMIP3 model average, and CMIP5 model average are shown from left to right, respectively. Figure 4. The local low-level (10-m to 500-mb mean) winds (m/s, vectors) and vertically integrated water vapor standardized anomalies (VIWV*, dimensionless, color fills) averaged over days when precipitation equals or exceeds the annual 99th percentile at every grid cell on the domain for (a) NARR, (b) the CMIP3 model average, and (c) the CMIP5 model average. Missing grid cells in the CMIP3 average (b) are the result of missing specific humidity values for some days in the CSIRO-Mk3.0 model output. Figure 5. Mean precipitation for the multi-model average of CMIP5 models analyzed in this paper (see Table 2). The mean from the historical simulations over the period 1979-1999 is shown in panels a through c. The absolute difference between the RCP8.5 simulation period (2079-2099) and historical period is shown in panels d through f, while the percent difference between RCP8.5 and historical is shown in h through i. The mean over annual, December-February (DJF), and June-August (JJA) days is shown from left to right, respectively. Figure 6. As in Fig. 4, but for the mean precipitation falling from the heaviest 1% of daily events (P99M, as defined in the text). Figure 7. The average error in predictions of cluster assignments for a sample of leftover grid cells versus number of clusters, based on applying V-fold cross validation to precipitation change histograms using 5 subsamples (see text for details). The analysis was applied to histograms of count differences in bins of raw precipitation or precipitation normalized by historical P99M for either the CMIP5 model average separately or the aggregate of all models (including the model average), following the legend. In all cases, the log of the count differences in the histograms was taken before applying the V-fold cross validation analysis. Values on the ordinate axis represent the sum of squared differences between the predicted centroid and grid cell histograms, averaged over all grid cells and subsamples left out in the cross validation process. Figure 8. The (c) cluster assignments and (a,b,d,e) mean histograms over the grid cells assigned to the respective clusters for the application of k-means clustering to difference histograms of annual daily precipitation for the model average (see text). The log of the count difference between the RCP8.5 and historical histograms was taken before applying cluster analysis. The histogram bars show the mean counts over all grid cells, the box and whiskers show the grid cell inter-quartile range (25th to 75th percentile, IQR, box) and 5th to 95th percentile (whiskers), and the stars indicate the minimum and maximum counts of all grid cells for the respective bin and cluster. Precipitation bin edges are 0, 0.5, 2.5, 5.0, 7.5…125 mm day-1. Figure 9. As in Fig. 8, but using precipitation normalized by the local historical P99M when generating histograms. The bin edges are 0, 0.01, 0.1, 0.2, 0.3…4, infinity. Figure 10. (left) The distance (see text) between the difference histogram at each individual grid cell and its corresponding assigned centroid histogram, using precipitation normalized by historical P99M and taking the log of count differences before applying cluster analysis. (right) Cluster histograms analogous to Fig. 9 but only using grid cells with distances less than 10 units from their respective centroid histogram to construct the histograms, as opposed to using all grid cells within the cluster. Figure 11. As in Fig. 9 but only using grid cells with a distance of 10 or more units from the respective cluster histogram in Fig. 10.