DOI: 10.25921/8hpf-a451
title: NOAA/WDS Paleoclimatology - Northern Hemisphere Observed and Simulated Tree Ring Width Data 1401-2000 CE

description: The detection and attribution (D&A) of paleoclimatic change to external radiative forcing relies on regression of statistical reconstructions on simulations. However, this procedure may be biased by assumptions of stationarity and univariate linear response of the underlying paleoclimatic observations. Here we perform a D&A study via regression of tree ring width (TRW) observations on TRW simulations which are forward modeled from climate simulations. Temperature and moisture-sensitive TRW simulations show distinct patterns in time and space. Temperature-sensitive TRW observations and simulations are significantly correlated for northern hemisphere averages, and their variation is attributed most closely to volcanically forced simulations. In decadally smoothed temporal fingerprints, we find the observed responses to be significantly larger and/or more persistent than the simulated responses. The pattern of simulated TRW of moisture-limited trees is consistent with the observed anomalies in the two years following major volcanic eruptions. We can for the first time attribute this spatiotemporal fingerprint in moisture limited tree-ring records to volcanic forcing. These results suggest that use of nonlinear and multivariate proxy system models in paleoclimatic detection and attribution studies may permit more realistic, spatially resolved and multivariate fingerprint detection studies, and evaluation of the climate sensitivity to external radiative forcing, than has previously been possible.
description: Results presented in Figs 2-7 of Franke et al (2022). fe23 netCDF, Matlab, and readme files added to study in October 2024 to include an additional variable, trwsSm, which is the climate interpretation.
Provided Keywords: proxy system modeling, VS-Lite, tree-ring width, parameter estimation, climate-sensor simulation, detection and attribution, moisture, temperature, surface, annual resolution.
files: fe22.nc (netcdf format, produced by Matlab R2020b update 4)
       fe22.mat (created in Matlab R2020b update 4)

 figure  variable    dimensions     description
 ======  ========    ==========     ===========

 2       slon        1619x1         TRW site longitudes (east)

 2       slat        1619x1         TRW site latitudes (north)

 2       trwsS       1619x4         sitewise estimation of TRW climate sensitivity (T = temperature, M = moisture, C = complacent, N = neither)

 3       long        64x1           longitude gridpoints

 3       latg        32x1           latitude gridpoints

 3       ntrwogTf    64x32          number of years for which gridded T-sensitive TRW observations are available (lon x lat)

 3       ntrwogMf    64x32          number of years for which gridded M-sensitive TRW observations are available (lon x lat)

 3       ntrwsgTf    64x32          number of years for which gridded T-sensitive TRW simulations are available (lon x lat)

 3       ntrwsgMf    64x32          number of years for which gridded M-sensitive TRW simulations are available (lon x lat)

 4       trwsgT_gT   4x64x32x600x12 simulated T-sensitive TRW, nondimensional temperature growth function  (nens x nlon x nlat x nt x nm)

 4       trwsgT_gM   4x64x32x600x12 simulated T-sensitive TRW, nondimensional moisture growth function  (nens x nlon x nlat x nt x nm)

 4       trwsgM_gT   4x64x32x600x12 simulated M-sensitive TRW, nondimensional temperature growth function  (nens x nlon x nlat x nt x nm)

 4       trwsgM_gM   4x64x32x600x12 simulated M-sensitive TRW, nondimensional moisture growth function  (nens x nlon x nlat x nt x nm)

 5       t           1x600          time (1401-2000 CE) (t)

 5       moT         1x600          mean observed T sensitive TRW (t)

 5       msT         1x600          mean observed M sensitive TRW (t)

 5       noTt        1x600          # gridpoints, mean observed T sensitive TRW (t)

 5       nsTt        1x600          # gridpoints, mean simulated T sensitive TRW (t)

 5       moM         1x600          mean observed T sensitive TRW (t)

 5       msM         1x600          mean observed M sensitive TRW (t)

 5       noMt        1x600          # gridpoints, mean observed M sensitive TRW (t)

 5       nsMt        1x600          # gridpoints, mean simulated M sensitive TRW (t)

 5       tf          1x590          11y centered time (1461-1995 CE) (t)

 5       moTf        1x590          mean 11y filt observed T sens TRW (t)

 5       msTf        1x590          mean 11y filt observed T sens TRW (t)

 5       moMf        1x590          mean 11y filt observed M sens TRW (t)

 5       msMf        1x590          mean 11y filt observed M sens TRW (t)

 6       crow        1x12           years for significant volcanic eruptions, from Crowley and Unterman (2013) (t)

 6       sigl        1x12           years for significant volcanic eruptions, from Sigl et al (2015) (t)

 6       lonlatg     2048x2         lon, lat gridpoint ordering for Fig 6 variables

 6       trwogTdat1g 2048x600       grid ave T sensitive observed TRW (lonlatg x t)

 6       trwogMdat1g 2048x600       grid ave M sensitive observed TRW (lonlatg x t)

 6       trwsgTdat1g 2048x600       grid ave T sensitive simulated TRW (lonlatg x t)

 6       trwsgMdat1g 2048x600       grid ave M sensitive simulated TRW (lonlatg x t)

 7       f7dat       3x2x3          detection and attribution results (figure panel (1,2,3) x attribution (ALL,VOLC) x percentile estimates (5th, 50th, 95th)

   files: fe23.nc (netcdf format, produced by Matlab R2020b update 4)
          fe23.mat (created in Matlab R2020b update 4)
Variables:
    trwo        
           Size:       22x278x600
           Dimensions: nregion,nseries,time
           Datatype:   double
           Attributes:
                       _FillValue = NaN
                       LongName   = '1401-2000 B14 TRW series values by region, series within region, and simulation time (1401-2000 CE)'
    trws        
           Size:       4x22x278x600x200
           Dimensions: nens,nregion,nseries,time,np
           Datatype:   double
           Attributes:
                       _FillValue = NaN
                       LongName   = '1401-2000 FE22 TRW simulation series values by HadCM3 ALL forcing ensemble member (1-4; Schurer et al 2013), B14 region, series within region, simulation time (1401-2000 CE), and validated parameter estimate (up to 200)'
    trwsSm      
           Size:       22x278
           Dimensions: nregion,nseries
           Datatype:   double
           Attributes:
                       _FillValue = NaN
                       LongName   = 'modal sensitivity of simulations by HadCM3 ALL forcing ensemble member across all ensemble members (1-4); Schurer et al 2013), B14 region, series within region: 1 = T sensitive, 2 = M sensitive, 3 = both T and M sensitive, 4 = neither T nor M sensitive; cf Franke et al (2022) Fig. 2'
    treetime    
           Size:       1159x1
           Dimensions: ttime
           Datatype:   double
           Attributes:
                       _FillValue = NaN
                       LongName   = 'observed timescale for chronos, 850-2008 CE.'
    chronos     
           Size:       22x278x1159
           Dimensions: nregion,nseries,ttime
           Datatype:   double
           Attributes:
                       _FillValue = NaN
                       LongName   = '850-2008 B14 TRW series values by region, series within region, and observation time (850-2008).'
    lonlat      
           Size:       2x22x278
           Dimensions: lonlat,nregion,nseries
           Datatype:   double
           Attributes:
                       _FillValue = NaN
                       LongName   = 'longitude and latitude of the B14 TRW series values by region and series within region'
    elevation   
           Size:       22x278
           Dimensions: nregion,nseries
           Datatype:   double
           Attributes:
                       _FillValue = NaN
                       LongName   = 'elevation of the B14 TRW series values by region and series within region'
    chronology  
           Size:       22x278x32
           Dimensions: nregion,nseries,nchars_chr
           Datatype:   char
           Attributes:
                       LongName = 'chronology names by region and series within region'
    country     
           Size:       22x278x22
           Dimensions: nregion,nseries,nchars_ctry
           Datatype:   char
           Attributes:
                       LongName = 'country names by region and series within region'
    investigator
           Size:       22x278x42
           Dimensions: nregion,nseries,nchars_cinv
           Datatype:   char
           Attributes:
                       LongName = 'investigator names by region and series within region'
    species     
           Size:       22x278x6
           Dimensions: nregion,nseries,nchars_csp
           Datatype:   char
           Attributes:
                       LongName = 'species names by region and series within region'
    sitename    
           Size:       22x278x51
           Dimensions: nregion,nseries,nchars_cn
           Datatype:   char
           Attributes:
                       LongName = 'site names by region and series within region'