UNIVERSITY OF MASSACHUSETTS LOWELL

PHOTOVOLTAIC PROGRAM

INTERNATIONAL SOLAR IRRADIATION DATABASE, Version 1.0

MONTHLY SOLAR IRRADIATION

     The main section of the database includes site location data

and monthly daily global horizontal irradiation, over the period of

record.  The irradiation unit used is kWh m^-2 day^-1.

     The data are presented in tables with country name headings,

23 columns, and 1 or 2 rows for each named site.  The first row

gives the monthly mean values for irradiation.  The following row,

identified by the symbol "S" in Column 9, gives the standard

deviations.  In many cases, we received only monthly values

averaged over several years, and not multiple years of monthly

values, so that the standard deviation could not be computed.

     The following table describes the information in each column.

COLUMN   HEADING & DESCRIPTION

  1      CODE:  An alpha-numeric code used to reference the row of

         data to the source information (of printed document).

  2      SITE:  The city, town or station where the data was

         recorded.

  3      LATITUDE:  The site latitude expressed in degrees.

  4      LATITUDE; HEMISPHERE (not labeled):  N or S for northern

         or southern hemisphere.  Lower case n or s indicates 

         latitude not given with site data, but obtained

         elsewhere.

  5      LONGITUDE:  The site longitude expressed in degrees.

  6      LONGITUDE; RELATIVE TO GREENWICH MERIDIAN (not labeled):E

         or W for east or west of the meridian.  Lower case e or w

         indicates latitude not given with site data, but obtained

         here.

  7      ELE:  Elevation of the site in meters above sea level.   

  8      YRS:  The number of years of data that are

         included

  9      D:  The type of data in columns 10-21:

         I - Monthly mean daily global horizontal irradiation.

         S - Unbiased standard deviation of global irradiation:

         where Si is the average value for year i, and Si bar is  

         the average over n years.

  10-21  JAN through DEC:  Monthly values of: mean daily global

         horizontal irradiation in kWh m-2 day-1; or unbiased standard

         deviation of the global irradiation in kWh m-2 day-1.

  22     AVG:  The yearly average of the irradiation data in      

         columns 10-21 for I data rows; or the standard deviation

         of the yearly averages for S data rows.

  23     SRC:  The nature of the data source.  The symbols used   

         are described below.  Detailed information on data       

         sources is given in printed document:

         P - Irradiance measured using pyranometer.

         H - Data calculated from cloud cover information or bright  

         sunshine hours.

         U - Data from source lacking information on instrumentation. 

     A few of the data sources made reference to the accepted

standards for reporting insolation data.  The standards include the

International Pyrheliometric Scale (IPS) adopted in 1956, and the

World Radiometric Reference (WRR); (WRR=IPS*1.022).  The World

Meteorological Organization (WMO) recommends use of the WRR.

Information in the printed document indicates the standard used

where known.

     Site names are listed alphabetically within their countries.

In some cases, data sources give differing spellings to what appear

(from coordinate data) to be the same location.  In general, we

respected the differences in spelling and present the source

version.  In some cases, the source lists site numbers or

experiment numbers rather than location names.  These sites are

included for their location data.