This disk accompanies "RECONSTRUCTING LARGE-SCALE CLIMATIC PATTERNS FROM TREE-
RING DATA: A DIAGNOSTIC ANALYSIS", H.C. Fritts, University of Arizona Press,
1991.  The disk contains (compressed) files of the reconstructed 
temperature and precipitation data for a network of weather observation sites
in the United States, plus display software.  The reconstructions along the
east and Gulf coasts of the United States do not verify and are therefore
unreliable.  PLEASE DO NOT EXPECT TO GET VALID RECONSTRUCTIONS FOR STATIONS
FROM THESE PARTICULAR REGIONS. In addition, the resonstructions for the
seasons are not as reliable as the reconstructions for the whole year and
the reconstructions for groups of years are more reliable than those for single
years because tree rings integrate information over a number of seasons 
sometimes including several years. (See the reference for more detailed 
descriptions of the strengths and weaknesses of these reconstructions.)
The best use of these programs is to compare reconstructions for groups of
years associated with a hypothesized condition to groups of years without the
hypothesized condition using the base and differemce maps.

The files on the disk are in a compressed format and must be expanded before
use.  Five megabytes of hard disk storage are required.  To expand the data 
files, create a directory for the reconstructions and copy the contents of this
disk into that directory.  When you unzipped the DIFMAP.ZIP you expanded the
programs and help files. Type TEMPDAT to expand the temperature 
reconstructions, and PRECPDAT to expand the precipitation reconstruction files.

You may then delete DIFMAP.ZIP, TEMPDAT.EXE, and PRECPDAT.EXE from the hard
disk to save space. Two versions of the display program DIFMAP are on the disk;
if your PC lacks a math coprocessor, type NOCOPRO to make the non-coprocessor
version active.  About 450 Kbytes of memory are required; you may need to
remove memory resident software to allow the programs to run on your system.

To begin the map program, type DIFMAP or MAPCL.  (MAPCL removes previously
created output files).  The reconstructions were made for a grid of
instrumental weather stations across the US (listed in file station.lst).
The program DIFMAP extracts the reconstructed data from the data files and
displays the information in map form. Output can be sent to a file and printed,
or displayed on an EGA or VGA color screen.  Screen output requires 2 to 3
minutes to generate, while creating the printer file takes only a few seconds.

The program SERIES displays reconstructed values for a single location, as
a graph or a numerical table.  Documentation for the programs is in the
files MANUAL.DOC and SERIES.DOC.  Caution is advised when intrepting these
plots.  The reconstructions are derived from large-scale climatic variations
so the station reconstructions will approximate the regional averages including
adjoining stations more closely than the data for the particular station. 
Please refer to the text for discussion of the methodology of climate
reconstructions, and potential limits in their application.
       

Copies of disk with the         
"Reconstructing Large Scale
Climatic Patterns from
Tree-Ring Data" are                        
available from:                   University of Arizona Press      
                                  1230 North Park Avenue           
                                  Suite 102                        
                                  Tucson, AZ 85719                
                                        USA
                                        
                                         or

                                  Harold C. Fritts
                                  DendroPower
                                  5703 North Lady Lane
                                  Tucson, AZ 85704-2905
                                         USA
               
For questions about this
disk, or for additional 
tree ring and other              
paleoclimate data sets,               
please contact:                   Mr. Bruce Bauer        
                                  Paleoclimate Group 
                                  National Geophysical Data Center     
                                  325 Broadway, EGC  
                                  Boulder, CO 80303 USA 
              
                                  Phone: (303) 497-6280
                                  email: bab@NGDC1.NGDC.NOAA.GOV
                                         BAB@PALEOSUN.NGDC.NOAA.GOV
