Western North America 500 Year Annual Temperature Reconstruction ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: Please cite original reference when using these data, plus the data file URL and date accessed. NAME OF DATA SET: Western North America 500 Year Annual Temperature Reconstruction LAST UPDATE: 4/2012 (Original receipt by WDC Paleo) CONTRIBUTORS: Wahl, E.R. and J.E. Smerdon IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2012-042 WDC PALEO CONTRIBUTION SERIES CITATION: Wahl, E.R. and J.E. Smerdon. 2012. Western North America 500 Year Annual Temperature Reconstruction. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2012-042. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Wahl, E.R. and J.E. Smerdon. 2012. Comparative performance of paleoclimate field and index reconstructions derived from climate proxies and noise-only predictors. Geophys. Res. Lett., 39, L06703, doi:10.1029/2012GL051086 ABSTRACT: The performance of climate field reconstruction (CFR) and index reconstruction methods is evaluated using proxy and non-informative predictor experiments. The skill of both reconstruction methods is determined using proxy data targeting the western region of North America. The results are compared to those targeting the same region, but derived from non-informative predictors comprising red-noise time series reflecting the full temporal autoregressive structure of the proxy network. All experiments are performed as probabilistic ensembles, providing estimated Monte Carlo distributions of reconstruction skill. Results demonstrate that the CFR skill distributions from proxy data are statistically distinct from and outperform the corresponding skill distributions generated from non-informative predictors; similar relative performance is demonstrated for the index reconstructions. In comparison to the CFR results using proxy information, the index reconstructions exhibit similar skill in calibration, but somewhat less skill in validation and a tendency to underestimate the amplitude of the validation period mean. GEOGRAPHIC REGION: Western North America PERIOD OF RECORD: 1500 - 1980 AD FUNDING SOURCES: US National Science Foundation (NSF) grant ATM0902436, US National Oceanic and Atmospheric Administration (NOAA) grants NA07OAR4310060 and NA10OAR4320137, US National Center for Atmospheric Research (NCAR) Weather and Climate Impacts Assessment Science Program. DATA FILE URLS: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/wahl2012/readme-wahl2012.txt ftp://ftp.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/wahl2012/SW_NAm_Recon_MeanT_1500-1980.dat ftp://ftp.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/wahl2012/SW_NAm_Recon_Grid_1500-1980.nc ftp://ftp.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/wahl2012/SW_NAm_Recon_Grid_Uncert_1500-1980.nc ftp://ftp.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/wahl2012/SW_NAm_Recon_Grid_Uncert_1500-1980_mean_sd.nc DESCRIPTION: This article presents a tree ring-based reconstruction of western North America annual temperature over 1500-1980, with 5x5 degree grid cell coverage for the region bounded by 30°-55°N and 95°-130°W. A 1000-member probabilistic ensemble derived by bootstrap methods is employed for characterization of uncertainty. A key result based on the ensemble methodology is that the most recent decades are, at the level of the bi-decadal average, very likely the warmest across the region during the past 500 years. The reconstruction is used in a side-by-side comparison with a parallel reconstruction driven by non-informative predictors that have the same temporal autoregressive structure as the tree ring data. The proxy-based reconstruction clearly outperforms the non-informative predictor-based reconstruction across a suite of calibration and validation skill measures.