Northern Hemisphere 1250 Year N-TREND Summer Temperature Reconstructions Wilson, R.J.S.; Anchukaitis, K.J.; Briffa, K.R.; Büntgen, U.; Cook, E.R.; D'Arrigo, R.D.; Davi, N.K.; Esper, J.; Frank, D.C.; Gunnarson, B.E.; Hegerl, G.C.; Helama, S.; Klesse, S.; Krusic, P.J.; Linderholm, H.W.; Myglan, V.S.; Osborn, T.J.; Rydval, M.; Schneider, L.; Schurer, A.P.; Wiles, G.; Zhang, P.; Zorita, E. Wilson, R.J.S. Anchukaitis, K.J. Briffa, K.R. Büntgen, U. Cook, E.R. D'Arrigo, R.D. Davi, N.K. Esper, J. Frank, D.C. Gunnarson, B.E. Hegerl, G.C. Helama, S. Klesse, S. Krusic, P.J. Linderholm, H.W. Myglan, V.S. Osborn, T.J. Rydval, M. Schneider, L. Schurer, A.P. Wiles, G. Zhang, P. Zorita, E. Air Temperature Reconstruction earth science/paleoclimate/climate reconstructions|tree ring (age,null,null,year Common Era,null,climate reconstructions|tree ring,null,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (surface temperature,null,null,standard deviation unit,summer,climate reconstructions|tree ring,composited,null,N,Z-score relative to the 1750-1950 period) earth science/paleoclimate/climate reconstructions|tree ring (surface temperature,null,two standard deviations lower bound,degree Celsius,May-Aug,climate reconstructions|tree ring,anomalized,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (surface temperature,null,null,degree Celsius,May-Aug,climate reconstructions|tree ring,anomalized,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (surface temperature,null,two standard deviations lower bound,degree Celsius,May-Aug,climate reconstructions|tree ring,anomalized|smoothed,null,N,smoothed 20 year spline) earth science/paleoclimate/climate reconstructions|tree ring (surface temperature,null,null,standard deviation unit,summer,climate reconstructions|tree ring,composited|smoothed,null,N,Z-score relative to the 1750-1950 period; smoothed 20 year spline) earth science/paleoclimate/instrumental (surface temperature,null,null,degree Celsius,May-Aug,instrumental,anomalized,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (surface temperature,null,null,degree Celsius,May-Aug,climate reconstructions|tree ring,anomalized|smoothed,null,N,smoothed 20 year spline) earth science/paleoclimate/tree ring (tree ring standardized growth index,null,null,null,null,tree ring,composited,null,N,null) earth science/paleoclimate/tree ring (tree ring standardized growth index,null,null,null,null,tree ring,composited|smoothed,null,N,smoothed 20 year spline) earth science/paleoclimate/tree ring (age,null,null,year Common Era,null,tree ring,null,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (surface temperature,null,two standard deviations upper bound,degree Celsius,May-Aug,climate reconstructions|tree ring,anomalized,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (surface temperature,null,two standard deviations upper bound,degree Celsius,May-Aug,climate reconstructions|tree ring,anomalized|smoothed,null,N,smoothed 20 year spline) earth science/paleoclimate/instrumental (surface temperature,null,null,degree Celsius,May-Aug,instrumental,anomalized|smoothed,null,N,smoothed 20 year spline) earth science/paleoclimate/reconstructions (Northern Hemisphere>LATITUDE >LONGITUDE ) Large-scale millennial length Northern Hemisphere (NH) temperature reconstructions have been progressively improved over the last 20 years as new datasets have been developed. This paper, and its companion (Part II, Anchukaitis et al. in prep), details the latest tree-ring (TR) based NH land air temperature reconstruction from a temporal and spatial perspective. This work is the first product of a consortium called N-TREND (Northern Hemisphere Tree-Ring Network Development) which brings together dendroclimatologists to identify a collective strategy for improving large-scale summer temperature reconstructions. The new reconstruction, N-TREND2015, utilises 54 records, a significant expansion compared with previous TR studies, and yields an improved reconstruction with stronger statistical calibration metrics. N-TREND2015 is relatively insensitive to the compositing method and spatial weighting used and validation metrics indicate that the new record portrays reasonable coherence with large scale summer temperatures and is robust at all time-scales from 918 to 2004 where at least 3 TR records exist from each major continental mass. N-TREND2015 indicates a longer and warmer medieval period (~900-1170) than portrayed by previous TR NH reconstructions and by the CMIP5 model ensemble, but with better overall agreement between records for the last 600 years. Future dendroclimatic projects should focus on developing new long records from data-sparse regions such as North America and eastern Eurasia as well as ensuring the measurement of parameters related to latewood density to complement ring-width records which can improve local based calibration substantially. STUDY NOTES: Northern Hemisphere Tree-Ring Network Development (N-TREND) consortium 2015 and 2017 Northern Hemisphere summer temperature reconstructions for AD 750-2011. Reconstructions are based on 54 tree-ring records. Field reconstructions netCDF data file (Anchukaitis et al. 2017) added 2 April 2018. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Wilson, R.J.S. Investigator : Anchukaitis, K.J. Investigator : Briffa, K.R. Investigator : Büntgen, U. Investigator : Cook, E.R. Investigator : D'Arrigo, R.D. Investigator : Davi, N.K. Investigator : Esper, J. Investigator : Frank, D.C. Investigator : Gunnarson, B.E. Investigator : Hegerl, G.C. Investigator : Helama, S. Investigator : Klesse, S. Investigator : Krusic, P.J. Investigator : Linderholm, H.W. Investigator : Myglan, V.S. Investigator : Osborn, T.J. Investigator : Rydval, M. Investigator : Schneider, L. Investigator : Schurer, A.P. Investigator : Wiles, G. Investigator : Zhang, P. Investigator : Zorita, E. 2016-01-15 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/19743 https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015tr.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015mxdrwl.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015regionc3.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2017grid.nc https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015.xlsx https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015regionc2.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015tr.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015mxdrwl.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015regionc3.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2017grid.nc https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015.xlsx https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015regionc2.txt English https://www.ncdc.noaa.gov/paleo/study/19743 https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015tr.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015mxdrwl.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015regionc3.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2017grid.nc https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015.xlsx https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/ntrend2015regionc2.txt Rob Wilson, Kevin Anchukaitis, Keith R. Briffa, Ulf Büntgen, Edward Cook, Rosanne D'Arrigo, Nicole Davi, Jan Esper, Dave Frank, Björn Gunnarson, Gabi Hegerl, Samuli Helama, Stefan Klesse, Paul J. Krusic, Hans W. Linderholm, Vladimir Myglan, Timothy J. Osborn, Miloš Rydval, Lea Schneider, Andrew Schurer, Greg Wiles, Peng Zhang, Eduardo Zorita2016Last millennium northern hemisphere summer temperatures from tree rings: Part I: The long term contextQuaternary Science Reviews1341-1810.1016/j.quascirev.2015.12.005http://www.sciencedirect.com/science/article/pii/S0277379115301888 Kevin J. Anchukaitis, Rob Wilson, Keith R. Briffa, Ulf Büntgen, Edward R. Cook, Rosanne D'Arrigo, Nicole Davi, Jan Esper, David Frank, Björn E. Gunnarson, Gabi Hegerl, Samuli Helama, Stefan Klesse, Paul J. Krusic, Hans W. Linderholm, Vladimir Myglan, Timothy J. Osborn, Peng Zhang, Eduardo Zorita2018Last millennium Northern Hemisphere summer temperatures from tree rings: Part II, spatially resolved reconstructionsQuaternary Science Reviews1631-2210.1016/j.quascirev.2017.02.020https://www.sciencedirect.com/science/article/pii/S0277379117301592 START YEAR: 750 AD * END YEAR: 2014 AD -180 0 180 90