North American Drought Variability PDSI Reconstructions: readme file
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              World Data Center for Paleoclimatology, Boulder
                                and 
                   NOAA Paleoclimatology Program
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NOTE: PLEASE CITE ORIGINAL REFERENCES WHEN USING THIS DATA!!!!!

CONTRIBUTORS: Cook, E.R.
NAME OF DATA SET: North American Drought Variability PDSI Reconstructions

IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2000-074.

SUGGESTED DATA CITATION: Cook, E.R., 2000, 
North American Drought Variability PDSI Reconstructions.  
International Tree-Ring Data Bank.  
IGBP PAGES/World Data Center-A for Paleoclimatology 
Data Contribution Series #2000-074.  
NOAA/NGDC Paleoclimatology Program, Boulder CO, USA.

ORIGINAL REFERENCE: Cook, E.R., Meko, D.M., Stahle, D.W. and 
Cleaveland, M.K. 1999. Drought reconstructions for the continental 
United States.  Journal of Climate, 12:1145-1162.	


LAST UPDATE:  12/2000 (Original receipt by WDC-A Paleo)
GEOGRAPHIC REGION: North America
PERIOD OF RECORD: 1700-1978 AD

LIST OF FILES: readme_pdsi.txt (this file), 
pdsiinst.xls (Microsoft Excel format, PDSI instrumental data),
pdsitree.xls (Microsoft Excel format, PDSI reconstructions 1700-1980),
pdsi.maxrecon.dat (ASCII text format, PDSI reconstructions for the 
full period of available treering data, length varies by grid point.
This file is in "decadal" format, each line of data contains 10 values
corresponding to 10 years begining with the year listed in column 1).


DESCRIPTION:
Tree Ring reconstructions of Palmer Drought Severity Index (PDSI)
across the continental United States and bordering areas of Canada
and Mexico. Drought variability study for the last ca. 100 years 
based on instrumental data, and on the last several centuries and 
millennia based on paleoclimatic proxy data. 
Hydrological conditions are displayed using the Palmer Drought 
Severity Index (PDSI).  The PDSI is a meteorological drought index 
used to assess the severity of dry or wet spells of weather. 
This index is based upon the principles of a moisture supply and 
demand balance. Negative PDSI values indicate dry conditions and 
positive values indicate wet conditions. 
PDSI values generally fall between -6 and +6.