# Northern Hemisphere 1262 year NTREND Assimilation Surface Temperature Reconstructions #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program #----------------------------------------------------------------------- # Template Version 4.0 # Encoding: UTF-8 # NOTE: Please cite original publication, online resource and date accessed when using this data. # If there is no publication information, please cite Investigator, study title, NOAA Landing Page URL, and date accessed. # # Description/Documentation lines begin with '#' followed by a space # Data lines have no '#' # # NOAA_Landing_Page: https://www.ncdc.noaa.gov/paleo/study/33632 # Landing_Page_Description: NOAA Landing Page of this file's parent study, which includes all study metadata. # # Study_Level_JSON_Metadata: https://www.ncei.noaa.gov/pub/data/metadata/published/paleo/json/noaa-recon-33632.json # Study_Level_JSON_Description: JSON metadata of this data file's parent study, which includes all study metadata. # # Data_Type: Climate Reconstructions # # Dataset_DOI: # # Science_Keywords: air temperature reconstruction #--------------------------------------- # Resource_Links # # Data_Download_Resource: https://www.ncei.noaa.gov/pub/data/paleo/reconstructions/king2021/king2021-ntrend-readme.txt # Data_Download_Description: NOAA Template File; Northern Hemisphere Temperature Reconstruction Metadata # # Data_Download_Resource: https://www.ncei.noaa.gov/pub/data/paleo/reconstructions/king2021/finalreconstructions/ # Data_Download_Description: Data Folder; Northern Hemisphere Temperature Reconstruction netCDF Files # # Original_Source_URL: https://www.ncdc.noaa.gov/paleo-search/study/19743 # Original_Source_Description: NTREND tree-ring chronologies, and Anchukaitis et al. (2017) CFR # # Original_Source_URL: https://esgf-node.llnl.gov/projects/esgf-llnl/ # Original_Source_Description: CMIP5 Climate Model output # # Original_Source_URL: https://www.earthsystemgrid.org/ # Original_Source_Description: CESM-LME climate model output # # Original_Source_URL: https://www.ncdc.noaa.gov/paleo-search/study/27850 # Original_Source_Description: LMR2.1 CFR # # Original_Source_URL: https://doi.org/10.5281/zenodo.3725030 # Original_Source_Description: Zhu et al. (2020) CFR # # Original_Source_URL: https://www.ncdc.noaa.gov/paleo-search/study/21090 # Original_Source_Description: Guillet et al. (2017) CFR # # Original_Source_URL: https://www.ncdc.noaa.gov/paleo-search/study/26850 # Original_Source_Description: Neukom et al (2019) CFR # #--------------------------------------- # Contribution_Date # Date: 2021-06-28 #--------------------------------------- # File_Last_Modified_Date # Date: 2021-06-28 #--------------------------------------- # Title # Study_Name: Northern Hemisphere 1262 year NTREND Assimilation Surface Temperature Reconstructions #--------------------------------------- # Investigators # Investigators: King, Jonathan M.; Anchukaitis, Kevin; Tierney, Jessica; Hakim, Gregory; Emile-Geay, Julien; Zhu, Feng; Wilson, Rob #--------------------------------------- # Description_Notes_and_Keywords # Description: Reconstructed surface temperature anomalies from 750 CE to 2011 CE. Reconstructions were generated by assimilating the NTREND network with output from general circulation models using offline ensemble Kalman Filters with stationary priors and linear, seasonal proxy-system models. Each file provides the reconstruction for one model in the reconstruction ensemble, or the ensemble-mean reconstruction. Each reconstruction includes the spatio-temporal reconstruction field, time series of the mean extratropical temperature index, and associated uncertainties. All temperature anomalies are relative to the 1951-1980 CE mean. The code and input datasets used to generate the reconstructions are available at https://doi.org/10.5281/zenodo.3989941 # Provided Keywords: Data assimilation, Kalman Filter, Tree-ring, Last Millennium #--------------------------------------- # Publication # Authors: King, Jonathan M.; Anchukaitis, Kevin; Tierney, Jessica; Hakim, Gregory; Emile-Geay, Julien; Zhu, Feng; Wilson, Rob # Published_Date_or_Year: 2021 # Published_Title: A Data Assimilation Approach to Last Millennium Temperature Field Reconstruction using a Limited High-Sensitivity Proxy Network # Journal_Name: Journal of Climate # Volume: # Edition: # Issue: # Pages: 1-64 # Report_Number: # DOI: 10.1175/JCLI-D-20-0661.1 # Online_Resource: # Full_Citation: # Abstract: We use the Northern Hemisphere Tree-Ring Network Development (NTREND) tree-ring database to examine the effects of using a small, highly-sensitive proxy network for paleotemperature data assimilation over the last millennium. We first evaluate our methods using pseudo-proxy experiments. These indicate that spatial assimilations using this network are skillful in the extratropical Northern Hemisphere and improve on previous NTREND reconstructions based on Point-by-Point regression. We also find our method is sensitive to climate model biases when the number of sites becomes small. Based on these experiments, we then assimilate the real NTREND network. To quantify model prior uncertainty, we produce 10 separate reconstructions, each assimilating a different climate model. These reconstructions are most dissimilar prior to 1100 CE, when the network becomes sparse, but show greater consistency as the network grows. Temporal variability is also underestimated before 1100 CE. Our assimilation method produces spatial uncertainty estimates and these identify treeline North America and eastern Siberia as regions that would most benefit from development of new millennial-length temperature-sensitive tree-ring records. We compare our multi-model mean reconstruction to five existing paleo-temperature products to examine the range of reconstructed responses to radiative forcing. We find substantial differences in the spatial patterns and magnitudes of reconstructed responses to volcanic eruptions and in the transition between the Medieval epoch and Little Ice Age. These extant uncertainties call for the development of a paleoclimate reconstruction intercomparison framework for systematically examining the consequences of proxy network composition and reconstruction methodology and for continued expansion of tree-ring proxy networks. #--------------------------------------- # Funding_Agency # Funding_Agency_Name: NOAA Climate Program Office # Grant: NA18OAR4310420, NA18OAR4310426, NA18OAR4310422 #--------------------------------------- # Funding_Agency # Funding_Agency_Name: National Science Foundation # Grant: AGS-1702423, AGS-1803946, AGS-1602301 #--------------------------------------- # Funding_Agency # Funding_Agency_Name: Heising-Simons Foundation # Grant: 2016-05 #--------------------------------------- # Site_Information # Site_Name: Northern Hemisphere Extratropics # Location: Northern Hemisphere # Northernmost_Latitude: 90 # Southernmost_Latitude: 30 # Easternmost_Longitude: -180 # Westernmost_Longitude: 180 # Elevation_m: #--------------------------------------- # Data_Collection # Collection_Name: King2021 NTREND Surf Temp Readme # First_Year: 750 # Last_Year: 2011 # Time_Unit: year CE # Core_Length_m: # Parameter_Keywords: air temperature # Notes: #--------------------------------------- # Chronology_Information # Chronology: #--------------------------------------- # Variables # PaST_Thesaurus_Download_Resource: https://www.ncdc.noaa.gov/paleo/skos/past-thesaurus.rdf # PaST_Thesaurus_Download_Description: Paleoenvironmental Standard Terms (PaST) Thesaurus terms, definitions, and relationships in SKOS format. # # Data variables follow that are preceded by "##" in columns one and two. # Variables list, one per line, shortname-tab-var components: what, material, error, units, seasonality, data type, detail, method, C or N for Character or Numeric data) # ## time age,,,year Common Era,,tree ring;climate reconstructions,,,N, ## lat latitude,,,degree north,,tree ring;climate reconstructions,,,N, ## lon longitude,,,degree east,,tree ring;climate reconstructions,,,N,0 to 360 ## T_bcc surface temperature,multiple proxies,,degree Celsius,May-Aug,tree ring;climate reconstructions,anomalized,,N,Individual spatial reconstructions using the bcc model; anomalized to the 1951-1980 MJJA mean ## T_var_bcc surface temperature,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior using the bcc model; units are Celsius^2 ## T_ccsm4 surface temperature,,,degree Celsius,May-Aug,tree ring;climate reconstructions,anomalized,,N,Individual spatial reconstructions using the ccsm4 model; anomalized to the 1951-1980 MJJA mean ## T_var_ccsm4 surface temperature,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior using the ccsm4 model; units are Celsius^2 ## T_cesm surface temperature,,,degree Celsius,May-Aug,tree ring;climate reconstructions,anomalized,,N,Individual spatial reconstructions using the cesm model; anomalized to the 1951-1980 MJJA mean ## T_var_cesm surface temperature,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior using the cesm model; units are Celsius^2 ## T_csiro surface temperature,,,degree Celsius,May-Aug,tree ring;climate reconstructions,anomalized,,N,Individual spatial reconstructions using the csiro model; anomalized to the 1951-1980 MJJA mean ## T_var_csiro surface temperature,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior using the csiro model; units are Celsius^2 ## T_fgoals surface temperature,,,degree Celsius,May-Aug,tree ring;climate reconstructions,anomalized,,N,Individual spatial reconstructions using the fgoals model; anomalized to the 1951-1980 MJJA mean ## T_var_fgoals surface temperature,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior using the fgoals model; units are Celsius^2 ## T_hadcm3 surface temperature,,,degree Celsius,May-Aug,tree ring;climate reconstructions,anomalized,,N,Individual spatial reconstructions using the hadcm3 model; anomalized to the 1951-1980 MJJA mean ## T_var_hadcm3 surface temperature,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior using the hadcm3 model; units are Celsius^2 ## T_ipsl surface temperature,,,degree Celsius,May-Aug,tree ring;climate reconstructions,anomalized,,N,Individual spatial reconstructions using the ipsl model; anomalized to the 1951-1980 MJJA mean ## T_var_ipsl surface temperature,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior using the ipsl model; units are Celsius^2 ## T_miroc surface temperature,,,degree Celsius,May-Aug,tree ring;climate reconstructions,anomalized,,N,Individual spatial reconstructions using the miroc model; anomalized to the 1951-1980 MJJA mean ## T_var_miroc surface temperature,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior using the miroc model; units are Celsius^2 ## T_mpi surface temperature,,,degree Celsius,May-Aug,tree ring;climate reconstructions,anomalized,,N,Individual spatial reconstructions using the mpi model; anomalized to the 1951-1980 MJJA mean ## T_var_mpi surface temperature,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior using the mpi model; units are Celsius^2 ## T_mri surface temperature,,,degree Celsius,May-Aug,tree ring;climate reconstructions,anomalized,,N,Individual spatial reconstructions using the mri model; anomalized to the 1951-1980 MJJA mean ## T_var_mri surface temperature,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior using the mri model; units are Celsius^2 ## T surface temperature,,,degree Celsius,May-Aug,tree ring;climate reconstructions,interpolated; averaged,,N,Mean of the spatial reconstruction ensemble ## T_posterior_var surface temperature,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,averaged,,N,Mean of the posterior variances in the spatial reconstruction ensemble; units are Celsius^2 ## T_model_var surface temperature,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior means in the spatial reconstruction ensemble; units are Celsius^2 ## ts_bcc temperature index,,,degree Celsius,May-Aug,tree ring;climate reconstructions,averaged; anomalized,,N,Individual reconstructions of the mean extratropical temperature index using the bcc model; anomalized to the 1951-1980 MJJA mean ## ts_var_bcc temperature index,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior for the mean extratropical temperature index using the bcc model; units are Celsius^2. ## ts_ccsm4 temperature index,,,degree Celsius,May-Aug,tree ring;climate reconstructions,averaged; anomalized,,N,Individual reconstructions of the mean extratropical temperature index using the ccsm4 model; anomalized to the 1951-1980 MJJA mean ## ts_var_ccsm4 temperature index,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior for the mean extratropical temperature index using the ccsm4 model; units are Celsius^2. ## ts_cesm temperature index,,,degree Celsius,May-Aug,tree ring;climate reconstructions,averaged; anomalized,,N,Individual reconstructions of the mean extratropical temperature index using the cesm model; anomalized to the 1951-1980 MJJA mean ## ts_var_cesm temperature index,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior for the mean extratropical temperature index using the cesm model; units are Celsius^2. ## ts_csiro temperature index,,,degree Celsius,May-Aug,tree ring;climate reconstructions,averaged; anomalized,,N,Individual reconstructions of the mean extratropical temperature index using the csiro model; anomalized to the 1951-1980 MJJA mean ## ts_var_csiro temperature index,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior for the mean extratropical temperature index using the csiro model; units are Celsius^2. ## ts_fgoals temperature index,,,degree Celsius,May-Aug,tree ring;climate reconstructions,averaged; anomalized,,N,Individual reconstructions of the mean extratropical temperature index using the fgoals model; anomalized to the 1951-1980 MJJA mean ## ts_var_fgoals temperature index,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior for the mean extratropical temperature index using the fgoals model; units are Celsius^2. ## ts_hadcm3 temperature index,,,degree Celsius,May-Aug,tree ring;climate reconstructions,averaged; anomalized,,N,Individual reconstructions of the mean extratropical temperature index using the hadcm3 model; anomalized to the 1951-1980 MJJA mean ## ts_var_hadcm3 temperature index,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior for the mean extratropical temperature index using the hadcm3 model; units are Celsius^2. ## ts_ipsl temperature index,,,degree Celsius,May-Aug,tree ring;climate reconstructions,averaged; anomalized,,N,Individual reconstructions of the mean extratropical temperature index using the ipsl model; anomalized to the 1951-1980 MJJA mean ## ts_var_ipsl temperature index,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior for the mean extratropical temperature index using the ipsl model; units are Celsius^2. ## ts_miroc temperature index,,,degree Celsius,May-Aug,tree ring;climate reconstructions,averaged; anomalized,,N,Individual reconstructions of the mean extratropical temperature index using the miroc model; anomalized to the 1951-1980 MJJA mean ## ts_var_miroc temperature index,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior for the mean extratropical temperature index using the miroc model; units are Celsius^2. ## ts_mpi temperature index,,,degree Celsius,May-Aug,tree ring;climate reconstructions,averaged; anomalized,,N,Individual reconstructions of the mean extratropical temperature index using the mpi model; anomalized to the 1951-1980 MJJA mean ## ts_var_mpi temperature index,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior for the mean extratropical temperature index using the mpi model; units are Celsius^2. ## ts_mri temperature index,,,degree Celsius,May-Aug,tree ring;climate reconstructions,averaged; anomalized,,N,Individual reconstructions of the mean extratropical temperature index using the mri model; anomalized to the 1951-1980 MJJA mean ## ts_var_mri temperature index,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior for the mean extratropical temperature index using the mri model; units are Celsius^2. ## ts temperature index,,,degree Celsius,May-Aug,tree ring;climate reconstructions,averaged,,N,Mean of the extratropical temperature index reconstruction ensemble ## ts_model_var temperature index,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,averaged,,N,Mean of the posterior variances for the extratropical temperature indices in the reconstruction ensemble; units are Celsius^2 ## ts_posterior_var temperature index,,variance,degree Celsius,May-Aug,tree ring;climate reconstructions,,,N,Variance of the posterior means for the extratropical temperature indices in the reconstruction ensemble; units are Celsius^2 #------------------------ # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing_Values: See netCDF file The netCDF files of temperature reconstruction data are in this folder: https://www.ncei.noaa.gov/pub/data/paleo/reconstructions/king2021/finalreconstructions Here is the file list: bcc-reconstruction.nc ccsm4-reconstruction.nc cesm-reconstruction.nc csiro-reconstruction.nc ensemble-mean-reconstruction.nc fgoals-reconstruction.nc hadcm3-reconstruction.nc ipsl-reconstruction.nc miroc-reconstruction.nc mpi-reconstruction.nc mri-reconstruction.nc