# European 1,150 Year Warm-Season Temperature and Hydroclimate Reconstructions
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#                World Data Service for Paleoclimatology, Boulder 
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#                     NOAA Paleoclimatology Program 
#             National Centers for Environmental Information (NCEI)
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# 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/27090 
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# Online_Resource: https://www1.ncdc.noaa.gov/pub/data/paleo/pages2k/EuroMed2k/ljungqvist2019/readme-ljungqvist2019.txt 
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# Original_Source_URL:  
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# Archive: Climate Reconstructions
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# Dataset DOI: 
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# Parameter_Keywords: air temperature, precipitation
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# Contribution_Date
#	Date: 2019-08-21
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# File_Last_Modified_Date
#	Date: 2019-08-21
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# Title
#	Study_Name: European 1,150 Year Warm-Season Temperature and Hydroclimate Reconstructions
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# Investigators
#	Investigators: Ljungqvist, F.C.; Seim, A.; Krusic, P.J.; González-Rouco, J.F.; Werner, J.P.; Cook, E.R.; Zorita, E.; Luterbacher, J.; Xoplaki, E.; Destouni, G.; García-Bustamante, E.; Aguilar, C.A.M.; Seftigen, K.; Wang, J.; Gagen, M.H.; Esper, J.; Solomina, O.; Fleitmann, D.; Büntgen, U.
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# Description_Notes_and_Keywords
#	Description: European temperature and hydroclimate reconstructions since 850 CE, plus underlying instrumental and proxy climate data. A contribution to the Past Global Changes (PAGES) 2k initiative (Euro-Med2k).
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#	Data file contents are as follows: 
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#	Instrumental_Data_1901_2003.zip: Instrumental gridded CRUTS3.25 instrumental data 1901–2003 for Europe of temperature, precipitation and the self-calibrating Palmer Drought Severity Index (scPDSI)
#	Early_instrumental_data.zip: Gridded temperature and precipitation data for Europe 1766–1900 from Casty et al. (2007)
#	Updated_EuroMed2k_temperature_JJA_reconstruction.zip: Gridded temperature June to August temperature reconstruction for Europe from tree-ring data and historical documentary data updated from Luterbacher et al. (2016)
#	Updated_Old_World_Drought_Atlas_scPDSI_values.txt: Original 0.5deg by 0.5deg tree-ring reconstructed self-calibrating Palmer Drought Severity Index (scPDSI) for Europe from the Old World Drought Atlas updated from Cook et al. (2015)
#	Updated_Old_World_Drought_Atlas_scPDSI_coordinates.txt: Coordinates to the grid-cells in updated Old World Drought Atlas
#	Updated_OWDA_variance_adjusted_regridded.zip: 5deg by 5deg regridded and variance adjusted updated Old World Drought Atlas
#	Regridded_model_simulation_data.zip: 5deg by 5deg regridded temperature, precipitation, and soil moisture output data for Europe 850–2005 for the global climate model simulations CCSM4 (Gent et al. 2011, Landrum et al 2013) and MPI-ESM-P (Giorgetta et al. 2013).
#	CCSM4 _preindustrial_control_simulation.zip: Data from the unforced CCSM4 pre-industrial control simulation with CCSM4 for Europe
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# Publication 
#	Authors: Fredrik Charpentier Ljungqvist, Andrea Seim, Paul J. Krusic, Jesús Fidel González-Rouco, Johannes P. Werner, Edward R. Cook, Eduardo Zorita, Jürg Luterbacher, Elena Xoplaki, Georgia Destouni, Elena García-Bustamante, Camilo Andrés Melo Aguilar, Kristina Seftigen, Jianglin Wang, Mary H. Gagen, Jan Esper, Olga Solomina, Dominik Fleitmann and Ulf Büntgen
#	Published_Date_or_Year: 2019-07-29    
#	Published_Title: European warm-season temperature and hydroclimate since 850 CE
#	Journal_Name: Environmental Research Letters
#	Volume: 14
#	Edition: 084015
#	Issue: 8
#	Pages:
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#	DOI: 10.1088/17489326/ab2c7e 
#	Online_Resource: https://iopscience.iop.org/article/10.1088/1748-9326/ab2c7e
#	Full_Citation: 
#	Abstract: The long-term relationship between temperature and hydroclimate has remained uncertain due to the short length of instrumental measurements and inconsistent results from climate model simulations. This lack of understanding is particularly critical with regard to projected drought and flood risks. Here we assess warm-season co-variability patterns between temperature and hydroclimate over Europe back to 850 CE using instrumental measurements, tree-ring based reconstructions, and climate model simulations. We find that the temperature-hydroclimate relationship in both the instrumental and reconstructed data turns more positive at lower frequencies, but less so in model simulations, with a dipole emerging between positive (warm and wet) and negative (warm and dry) associations in northern and southern Europe, respectively. Compared to instrumental data, models reveal a more negative co-variability across all timescales, while reconstructions exhibit a more positive co-variability. Despite the observed differences in the temperature-hydroclimate co-variability patterns in instrumental, reconstructed and model simulated data, we find that all data types share relatively similar phase-relationships between temperature and hydroclimate, indicating the common influence of external forcing. The co-variability between temperature and soil moisture in the model simulations is overestimated, implying a possible overestimation of temperature-driven future drought risks.
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# Funding_Agency 
#	Funding_Agency_Name: US National Science Foundation
#	Grant: PAGES2k
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# Funding_Agency 
#	Funding_Agency_Name: Swiss National Science Foundation
#	Grant: PAGES2k
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# Site_Information 
#	Site_Name: Europe-Mediterranean
#	Location: Europe
#	Country:  
#	Northernmost_Latitude: 72
# 	Southernmost_Latitude: 27
# 	Easternmost_Longitude: 45
# 	Westernmost_Longitude: -12
# 	Elevation:  
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# Data_Collection   
#	Collection_Name: Ljungqvist2019 
#	Earliest_Year: 850
#	Most_Recent_Year: 2003
#	Time_Unit: Year CE
#	Core_Length: 
#	Notes: 
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