# North America-North Pacific 500 hPa Geopotential Height Reconstruction #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program # National Centers for Environmental Information (NCEI) #----------------------------------------------------------------------- # # NOTE: Please cite Publication, and Online_Resource and date accessed when using these data. # If there is no publication information, please cite Investigators, Title, and Online_Resource and date accessed. # # Online_Resource: https://www.ncdc.noaa.gov/paleo/study/19103 # Online_Resource: http://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/wise2014gph.nc # Online_Resource: http://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/wise2014gph-ext.nc # Online_Resource: http://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/readme-wise2014gph.txt # # Original_Source_URL: # # Description/Documentation lines begin with # # Data lines have no # # # Archive: Climate Reconstructions # # Parameter_Keywords: pressure, Little Ice Age, circulation, hydroclimate, geopotential height #-------------------- # Contribution_Date # Date: 2015-08-12 #-------------------- # Title # Study_Name: North America-North Pacific 500 hPa Geopotential Height Reconstruction #-------------------- # Investigators # Investigators: Wise, E.K.; Dannenberg, M.P. #-------------------- # Description_and_Notes # Description: Tree-ring-based reconstruction of cool-season (Oct-Mar) 500hPa Geopotential Height Anomalies since 1500AD # for the North Pacific and North America on a 2 x 2 degree grid (unitless z-scores). # Reconstruction is based on tree-ring width measurements from the International Tree Ring Data Bank (ITRDB): # https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets/tree-ring # Instrumental data (monthly mean 500 hPa GPH values) were supplied by NCEP/NCAR Twentieth Century Reanalysis project V2 # (http://www.esrl.noaa.gov/psd/data/gridded/data.20thC_ReanV2.html). These data (meters) were converted to cool-season (Oct-Mar) # anomalies (unitless z-scores standardized to the 1872-1971 calibration period; assigned to the ending year of the season). # See Wise and Dannenberg (2014) for more complete description of data and methods. # # Validation and reconstruction variables with no modifier (e.g., ReconGPHanoms) are the version of the reconstruction # published in Wise and Dannenberg (2014), filename wise2014gph.nc. # Two additional versions of the reconstruction were added 3-February-2016, filename wise2014gph-ext. # The first is identical to the Wise and Dannenberg (2014) version except that the variance in the # reconstruction has been scaled to the calibration period. The associated variable names are modified with "_VS", # e.g., ReconGPHanoms_VS. The validation statistics are the same for the Wise and Dannenberg (2014) reconstruction # and the ReconGPHanoms_VS reconstruction. The second was created using a different pre-screening approach in which # the False Discovery Rate (FDR; see D. S. Wilks, 2006: On "field significance" and the false discovery rate. # J. Appl. Meteorol. Clim. 45, 1181–1189) was used to select tree-ring chronologies to include in the model # rather than correlation-based selection. The variance in this version of the reconstruction has also been scaled to # the calibration period and associated variable names are modified with "_FDR", e.g., ReconGPHanoms_FDR. # Validation statistics for the FDR reconstrucion are included as separate variables. # # Description of variables in netCDF file wise2014gph.nc: # # InstGPHanoms: Cool-season (Oct-Mar) 500hPa GPH anomalies (unitless z-scores standardized to the 1872-1971 calibration period; assigned to the ending year of the season) calculated from instrumental data (monthly mean 500 hPa GPH values) supplied by NCEP/NCAR Twentieth Century Reanalysis project V2 (http://www.esrl.noaa.gov/psd/data/gridded/data.20thC_ReanV2.html) # ReconGPHanoms: Reconstructed cool-season (Oct-Mar) 500hPa GPH anomalies (unitless z-scores; assigned to the ending year of the season) # Recon_SDR: standard deviation ratio (entire period to calibration period) # Recon_error: Error as calculated by RegEm-ridge program (see T. Schneider, 2001: Analysis of incomplete climate data: Estimation of mean values and covariance matrices and imputation of missing values. Journal of Climate, 14, 853-871) # Validation_CE: coefficient of efficiency (CE) # Validation_R: Pearson correlation coefficient (R) between the predicted and observed data # Validation_RMSE: root mean squared error (RMSE) # Validation_SDR: standard deviation ratio (SDR) # Validation_bias: mean bias # Validation_data: GPH estimates produced by the leave-decade-out calibration/validation, 1872-1971 # Validation_p: p-values associated with correlation coefficients # lat: latitude vector for the gridded GPH data # lon: longitude vector for the gridded GPH data # year_inst: year vector for instrumental time period # year_recon: year vector for reconstructed time period # InstGPHm: Instrumental cool-season (Oct-Mar) 500 hPa GPH coverted back to meters. # ReconGPHm: Reconstructed cool-season (Oct-Mar) 500 hPa GPH coverted back to meters. # # # Description of variables in netCDF file wise2014gph-ext.nc: # # InstGPHanoms: Cool-season (Oct-Mar) 500hPa GPH anomalies (unitless z-scores standardized to the 1872-1971 calibration period; assigned to the ending year of the season) calculated from instrumental data (monthly mean 500 hPa GPH values) supplied by NCEP/NCAR Twentieth Century Reanalysis project V2 (http://www.esrl.noaa.gov/psd/data/gridded/data.20thC_ReanV2.html) # ReconGPHanoms: Reconstructed cool-season (Oct-Mar) 500hPa GPH anomalies (unitless z-scores; assigned to the ending year of the season) # ReconGPHanoms_VS: Reconstructed cool-season (Oct-Mar) 500hPa GPH anomalies (unitless z-scores; assigned to the ending year of the season) with variance scaled to the calibration period # Recon_SDR: standard deviation ratio (entire period to calibration period) for the Wise and Dannenberg (2014) version of the reconstruction in which variance was not scaled to the calibration period # Recon_error: Error as calculated by RegEm-ridge program (see T. Schneider, 2001: Analysis of incomplete climate data: Estimation of mean values and covariance matrices and imputation of missing values. Journal of Climate, 14, 853-871) # Validation_CE: coefficient of efficiency (CE) # Validation_R: Pearson correlation coefficient (R) between the predicted and observed data # Validation_RMSE: root mean squared error (RMSE) # Validation_SDR: standard deviation ratio (SDR) # Validation_bias: mean bias # Validation_data: GPH estimates produced by the leave-decade-out calibration/validation, 1872-1971 # Validation_p: p-values associated with correlation coefficients # ReconGPHanoms_FDR: Reconstructed cool-season (Oct-Mar) 500hPa GPH anomalies (unitless z-scores; assigned to the ending year of the season) using False Discovery Rate (FDR; see D. S. Wilks, 2006: On "field significance" and the false discovery rate. J. Appl. Meteorol. Clim. 45, 1181–1189) for pre-screening and with variance scaled to the calibration period # Validation_CE_FDR: coefficient of efficiency (CE) for FDR version of the reconstruction # Validation_R_FDR: Pearson correlation coefficient (R) between the predicted and observed data for FDR version of the reconstruction # Validation_RMSE_FDR: root mean squared error (RMSE) for FDR version of the reconstruction # Validation_SDR_FDR: standard deviation ratio (SDR) for FDR version of the reconstruction # Validation_bias_FDR: mean bias for FDR version of the reconstruction # Validation_data_FDR: GPH estimates produced by the leave-decade-out calibration/validation, 1872-1971 for FDR version of the reconstruction # Validation_p_FDR: p-values associated with correlation coefficients # lat: latitude vector for the gridded GPH data for FDR version of the reconstruction # lon: longitude vector for the gridded GPH data # year_inst: year vector for instrumental time period # year_recon: year vector for reconstructed time period # InstGPHm: Instrumental cool-season (Oct-Mar) 500 hPa GPH converted back to meters # ReconGPHm: Reconstructed cool-season (Oct-Mar) 500 hPa GPH converted back to meters # ReconGPHm_VS: Variance-scaled reconstructed cool-season (Oct-Mar) 500 hPa GPH converted back to meters # ReconGPHm_FDR: FDR version of reconstructed cool-season (Oct-Mar) 500 hPa GPH converted back to meters # # #-------------------- # Publication # Authors: Erika K. Wise and Matthew P. Dannenberg # Published_Date_or_Year: 2014-09-11 # Published_Title: Persistence of pressure patterns over North America and the North Pacific since AD 1500 # Journal_Name: Nature Communications # Volume: 5 # Edition: # Issue: 4912 # Pages: # Report_Number: # DOI: 10.1038/ncomms5912 # Online_Resource: http://www.nature.com/ncomms/2014/140911/ncomms5912/full/ncomms5912.html # Full_Citation: # Abstract: Changes in moisture delivery to western North America are largely controlled by interrelated, synoptic-scale atmospheric pressure patterns. Long-term records of upper-atmosphere pressure and related circulation patterns are needed to assess potential drivers of past severe droughts and evaluate how future climate changes may impact hydroclimatic systems. Here we develop a tree-ring-based climate field reconstruction of cool-season 500 hPa geopotential height on a 2 x 2 degree grid over North America and the North Pacific to AD 1500 and examine the frequency and persistence of preinstrumental atmospheric pressure patterns using Self-Organizing Maps. Our results show extended time periods dominated by a set of persistent upper-air pressure patterns, providing insight into the atmospheric conditions leading to periods of sustained drought and pluvial periods in the preinstrumental past. A striking shift from meridional to zonal flow occurred at the end of the Little Ice Age and was sustained for several decades. #------------------ # Funding_Agency # Funding_Agency_Name: US National Science Foundation # Grant: AGS-1102757 #------------------ # Site_Information # Site_Name: North America-North Pacific # Location: Geographic Region>Western Hemisphere # Country: # Northernmost_Latitude: 70.0 # Southernmost_Latitude: 14.0 # Easternmost_Longitude: -70.0 # Westernmost_Longitude: 160.0 # Elevation: m #------------------ # Data_Collection # Collection_Name: Wise2014GPH # Earliest_Year: 1500 # Most_Recent_Year: 2010 # Time_Unit: AD # Core_Length: m # Notes: #------------------ # Chronology_Information # Chronology: # #----------------