# Living Blended Drought Atlas (LBDA) Version 2 recalibrated reconstruction of United States Summer PMDI over the last 2000 years
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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/22454
#       Description: NOAA Landing Page
# Online_Resource: https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDP-v2/LBDPv2-2017-columns.txt
#       Description: NOAA location of this template
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# Original_Source_URL: https://www.ncdc.noaa.gov/paleo/study/19119 
#       Description: PMDI data is from this Cook et al. 2000 year drought reconstruction
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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: precipitation
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# Contribution_Date
#	Date:  2017-08-03
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# File_Last_Modified_Date
#	Date:  2017-08-03
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# Title
#	Study_Name: Living Blended Drought Atlas (LBDA) version 2 recalibrated reconstruction of United States Summer PMDI over the last 2000 years
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# Investigators
#	Investigators:  Gille, E.P.; Wahl, E.R.; Vose, R.S.; Cook, E.R.
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# Description_Notes_and_Keywords
#	Description: The half degree gridded Jun-Aug PMDI reconstructions from Cook et al. (2010) were recalibrated using the Global Historical Climatology Network (GHCN) 5km grid PMDI data. The 5km data were first upscaled to match the original half-degree grid. The recalibration was performed using a kernel density distribution mapping (KDDM) technique outlined in McGinnis et al. (2015) using an R-package provided by Seth McGinnis. We used a 50-year recalibration period covering 1929-1978 CE. We also adjusted each grid point's mean PMDI value for the recalibration period to be zero to avoid importing wet or dry bias into the recalibration. The recalibrated data set covers the continental United States just as the GHCN instrumental data does. Since instrumental data was used for 1979-2005 CE in the Cook data set, only the years 0 - 1978 CE were recalibrated. The 1979-2017 instrumental years were filled in using data from NCEI's GHCN 5km instrumental PMDI data. November 2017: The PMDI data sets were updated by recalibrating with the Oct 2017 GHCN PMDI data, and the post-recalibration years (1979-2017) were filled in using that same data. The images were all updated using the new data sets.
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# Publication 
#	Authors: Cook, E.R., Seager, R., Heim, R.R., Vose, R.S., Herweijer, C., and Woodhouse, C. 
#	Published_Date_or_Year: 2010  
#	Published_Title: Megadroughts in North America: Placing IPCC projections of hydroclimatic change in a long-term paleoclimate context
#	Journal_Name: Journal of Quaternary Science
#	Volume: 25
#	Edition: 
#	Issue: 1
#	Pages: 48-61
#	Report_Number: 
#	DOI: 10.1002/jqs.1303
#	Online_Resource: 
#	Full_Citation: 
#	Abstract: IPCC Assessment Report 4 model projections suggest that the subtropical dry zones of the world will both dry and expand poleward in the future due to greenhouse warming. The US Southwest is particularly vulnerable in this regard and model projections indicate a progressive drying there out to the end of the 21st century. At the same time, the USA has been in a state of drought over much of the West for about 10 years now. While severe, this turn of the century drought has not yet clearly exceeded the severity of two exceptional droughts in the 20th century. So while the coincidence between the turn of the century drought and projected drying in the Southwest is cause for concern, it is premature to claim that the model projections are correct. At the same time, great new insights into past drought variability over North America have been made through the development of the North American Drought Atlas from tree rings. Analyses of this drought atlas have revealed past megadroughts of unprecedented duration in the West, largely in the Medieval period about 1000 years ago. A vastly improved Living Blended Drought Atlas (LBDA) for North America now under develop- ment reveals these megadroughts in far greater detail. The LBDA indicates the occurrence of the same Medieval megadroughts in the West and similar-scale megadroughts in the agriculturally and commercially important Mississippi Valley. Possible causes of these megadroughts and their implications for the future are discussed.
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# Funding_Agency 
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# Site_Information 
#	Site_Name: Continental United States half-degree grid
#	Location: United States
#	Country:  
#	Northernmost_Latitude:  49
# 	Southernmost_Latitude:  25
# 	Easternmost_Longitude:  -67
# 	Westernmost_Longitude:  -124.5
# 	Elevation:  
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# Data_Collection   
#	Collection_Name:  CONUS Recalib PMDI Gille2017
#	Earliest_Year:  0
#	Most_Recent_Year:  2005
#	Time_Unit:  CE
#	Core_Length: 
#	Notes: 
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# Species
#	Species_Name: 
#	Common_Name:
#	Tree_Species_Code: 
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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.
# *** MORE DETAILED INSTRUCTIONS are available at www1.ncdc.noaa.gov/pub/data/paleo/templates/Variable_naming_guide.pdf
# 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, additional information) 
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## year	age, , , years CE, , , , ,N,
## lat	latitude, , , degrees North, ,climate reconstructions , , ,N,
## lon	longitude, , , degrees East, ,climate reconstructions , , ,N,
## PMDI	palmer modified drought index, , , unitless,Jun-Aug ,climate reconstructions , , ,N,
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# Data:
# Data lines follow (have no #)
# Data line format - tab-delimited text, variable short name as header
# Missing Values:  NA
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The data are available as:
a text file with columns described by the variables above - https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDP-v2/lbda-v2_pmdi_kddm_cols_2017.txt
a netCDF file- https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDP-v2/lbda-v2_pmdi_kddm_2017.nc
a text file with each row containing a year's data - https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDP-v2/lbda-v2_pmdi_kddm_rowyears_2017.txt