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Environmental Modeling Community of Practice


GCSOLAR program is a set of routines that computes direct photolysis rates and half-lives of pollutants in the aquatic environment. The half-lives are calculated as a function of season, latitude, time-of-day, depth in water bodies, and ozone layer thickness.

This program operates in an interactive screen mode to facilitate data and program command entry by the user. Input values, with few restrictions, are format free. The user controls program flow by entering program execution commands. This release (1.10 February 1988 and 1.20 July 1999) of the GCSOLAR program differs from earlier versions of the program in that it permits the user to compute photolysis rate constants as a function of elevation above sea level. This is implemented with the GCSOLAR ELEVATION command.

For a complete discussion of the chemistry associated with this program, refer to the publication, "Rates of Direct Photolysis in Aquatic Environment", R. G. Zepp and D. M. Cline, Environmental Science and Technology, 11:4, PP 359- 366 (1977).

Current Version: 1.2
Release Date: July 1999
Development Status: General Release
Development Information: Release Notes - changes and known deficiencies
Operating System: 16-bit MS-DOS
Development Language: FORTRAN
Intended Audience: Environmental Scientist/Biologist
Key Words: solar, photolysis, half-life, pollutant, aquatic, ozone
Related Web Sites: None Available
Text Files (ASCII Format)
File Name File Description
ABSTRACT.TXT Summary of functions, theory, and applicability.
README.TXT Important installation and usage information.
Download Files
File Type /
File Name /
Format /
File Description
Install /
Self-extracting Executable /
1.2 MB
Setup file for version 1.2 of the GCSOLAR system. INSTALGC.EXE must be executed from DOS or a DOS command prompt. Setup file includes documentation. See README.TXT for important installation instructions.
Document /