# Northern Hemisphere 1250 Year N-TREND Summer Temperature Field Reconstructions
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#                World Data Service for Paleoclimatology, Boulder 
#                                  and 
#                     NOAA Paleoclimatology Program 
#             National Centers for Environmental Information (NCEI)
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# Template Version 3.0
# Encoding: UTF-8
# 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. 
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# Online_Resource: https://www.ncdc.noaa.gov/paleo/study/19743 
#       Description: NOAA Landing Page
# Online_Resource: https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/readme-ntrend2017grid.txt
#       Description: NOAA location of the template
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# Original_Source_URL:  
#       Description:
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# Description/Documentation lines begin with #
# Data lines have no #
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# Archive: Climate Reconstructions
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# Dataset DOI: 
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# Parameter_Keywords: air temperature
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# Contribution_Date
#	Date: 2016-02-01
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# File_Last_Modified_Date
#	Date: 2018-04-01
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# Title
#	Study_Name: Northern Hemisphere 1250 Year N-TREND Summer Temperature Field Reconstructions
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# Investigators
#	Investigators: Anchukaitis, K.J.; Wilson, R.; Briffa, K.R.; Büntgen, U.; Cook, E.R.; D'Arrigo, R.; Davi, N.; Esper, J.; Frank, D.; Gunnarson, B.E.; Hegerl, G.; Helama, S.; Klesse, S.; Krusic, P.J.; Linderholm, H.W.; Myglan, V.; Osborn, T.J; Zhang, P.; Zorita, E.
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# Description_Notes_and_Keywords
#	Description: Northern Hemisphere Tree-Ring Network Development (N-TREND) consortium 2017 Northern Hemisphere summer temperature field reconstructions for AD 750-2011.  
#	Added to wilson et al. 2015 regional reconstruction.  Data presented in a netCDF file with the following variables:
# netcdf anchukaitis2017_ntrend {
# dimensions:
# 	longitude = 72 ;
# 	latitude = 11 ;
# 	time = 1265 ;
# variables:
# 	double longitude(longitude) ;
# 		longitude:long_name = "Longitude" ;
# 		longitude:units = "degrees_east" ;
# 	double latitude(latitude) ;
# 		latitude:long_name = "Latitude" ;
# 		latitude:units = "degrees_north" ;
# 	double time(time) ;
# 		time:long_name = "Time" ;
# 		time:units = "Year CE" ;
# 	double t_all(longitude, latitude, time) ;
# 		t_all:long_name = "Reconstructed temperatures (degrees C anomaly relative to the mean of 1961 to 1990)" ;
# 		t_all:units = "degrees_C_anomaly" ;
# 		t_all:missing_value = -9999. ;
# 	double t_filtered(longitude, latitude, time) ;
# 		t_filtered:long_name = "Reconstructed temperatures (degrees C anomaly relative to the mean of 1961 to 1990), only values with RE>0" ;
# 		t_filtered:units = "degrees_C_anomaly" ;
# 		t_filtered:missing_value = -9999. ;
# 	double r2c(longitude, latitude, time) ;
# 		r2c:long_name = "Adjusted calibration R2" ;
# 		r2c:units = "r2c_adj" ;
# 		r2c:missing_value = -9999. ;
# 	double r2v(longitude, latitude, time) ;
# 		r2v:long_name = "Validation R2" ;
# 		r2v:units = "r2v" ;
# 		r2v:missing_value = -9999. ;
# 	double RE(longitude, latitude, time) ;
# 		RE:long_name = "Reduction of Error (RE) statistic" ;
# 		RE:units = "RE" ;
# 		RE:missing_value = -9999. ;
# 	double CE(longitude, latitude, time) ;
# 		CE:long_name = "Coffiecient of Efficiency (CE)" ;
# 		CE:units = "CE" ;
# 		CE:missing_value = -9999. ;
# 
# // global attributes:
# 		:creator = "Kevin Anchukaitis, kanchukaitis@email.arizona.edu - please contact with any questions or bugfixes" ;
# 		:original\ reference = "Anchukaitis, K.J., R. Wilson, K. Briffa, U. Buntgen, E.R. Cook, R.D. D\'Arrigo, N. Davi, J. Esper, D. Frank, B. Gunnarson, G. Hegerl, S. Helama, S. Klesse, P.J. Krusic, H. Linderholm, V. Myglan, T. J. Osborn, Z. Peng, M. Rydval, L. Schneider, A. Schurer, G. Wiles and E. Zorita, Last millennium northern hemisphere summer temperatures from tree rings: Part II, spatially resolved reconstructions, Quaternary Science Reviews, 163, 1--22,doi: 10.1016/j.quascirev.2017.02.020, 2017" ;
# 		:creation_date = "08-Mar-2018 14:34:46" ;
# 		:user\ notes = "We strongly recommend using the RE filtered series (t_filtered) included here, and not the full unfiltered field (t_all) since the full field (t_all) will still give a reconstructed value even when reconstruction skill is low" ;
# }
# 
#--------------------
# Publication 
#	Authors: 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 Zorita
#	Published_Date_or_Year: 2017-05-01      
#	Published_Title: Last millennium Northern Hemisphere summer temperatures from tree rings: Part II, spatially resolved reconstructions
#	Journal_Name: Quaternary Science Reviews
#	Volume: 163
#	Edition: 
#	Issue: 
#	Pages: 1-22
#	Report_Number: 
#	DOI: 10.1016/j.quascirev.2017.02.020
#	Online_Resource: https://www.sciencedirect.com/science/article/pii/S0277379117301592
#	Full_Citation: 
#	Abstract: Climate field reconstructions from networks of tree-ring proxy data can be used to characterize regional-scale climate changes, reveal spatial anomaly patterns associated with atmospheric circulation changes, radiative forcing, and large-scale modes of ocean-atmosphere variability, and provide spatiotemporal targets for climate model comparison and evaluation. Here we use a multiproxy network of tree-ring chronologies to reconstruct spatially resolved warm season (May-August) mean temperatures across the extratropical Northern Hemisphere (40-90N) using Point-by-Point Regression (PPR). The resulting annual maps of temperature anomalies (750-1988 CE) reveal a consistent imprint of volcanism, with 96% of reconstructed grid points experiencing colder conditions following eruptions. Solar influences are detected at the bicentennial (de Vries) frequency, although at other time scales the influence of insolation variability is weak. Approximately 90% of reconstructed grid points show warmer temperatures during the Medieval Climate Anomaly when compared to the Little Ice Age, although the magnitude varies spatially across the hemisphere. Estimates of field reconstruction skill through time and over space can guide future temporal extension and spatial expansion of the proxy network.
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# Funding_Agency 
#	Funding_Agency_Name: 
#	Grant: 
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# Site_Information 
#	Site_Name: Northern Hemisphere
#	Location: Geographic Region>Northern Hemisphere
#	Country:  
#	Northernmost_Latitude: 90.0
#	Southernmost_Latitude:  0.0
#	Easternmost_Longitude: 180.0
#	Westernmost_Longitude: -180.0
#	Elevation:  m  
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# Data_Collection   
#	Collection_Name: N-TREND2017
#	Earliest_Year: 750
#	Most_Recent_Year: 2014 
#	Time_Unit: AD
#	Core_Length: m
#	Notes: 
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# Chronology_Information
#	Chronology: 
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# Variables 
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# Data variables follow are preceded by "##" in columns one and two.
# Data line variables format:  one per line, shortname-tab-variable components (what, material, error, units, seasonality, data type,detail, method, C or N for Character or Numeric data, free text) 
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## age_AD	age, , , AD, , , , ,N
## tempanom-MJJA	surface temperature anomaly, , , degrees C, May-August, climate reconstructions, NTREND2015, ,N 
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# Data:
# Data lines follow (have no #)
# Data line format - tab-delimited text, variable short name as header
# Missing Values:  
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age_AD	tempanom-MJJA