North American Drought Atlas: A History of Meteorological Drought Reconstructed from 835 Tree-Ring Chronologies for the Past 2,005 Years

The North American Drought Atlas, is an HTML web browser program that provides
access to 286 annual drought reconstructions extending as far back as 1,992
years into the past. The reconstructions are derived from 835 exactly dated,
annual tree-ring chronologies. Data consists of the Palmer Drought Severity
Index (PDSI).

The North American instrumental PDSI grid developed and used in the Atlas for
reconstruction has a resolution of 2.5 degrees latitude by 2.5 degrees
longitude. It is patterned after a global study of drought by Dai et al.
(1998). The Atlas grid is composed of 286 grid points covering most of North
America.

This Atlas was developed by Paul J. Krusic and Edward R. Cook, Tree-Ring
Laboratory, Lamont-Doherty Earth Observatory of Columbia University, Palisades,
NY USA through support from the National Science Foundation, Division of
Atmospheric Sciences, Award ATM 03-22403.