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NAME

i.sunhours - creates a sunshine hours map

KEYWORDS

sunshine, hours, daytime

SYNOPSIS

i.sunhours
i.sunhours help
i.sunhours dayofyear=name latitude=name output=name [--overwrite] [--verbose] [--quiet]

Flags:

--overwrite
Allow output files to overwrite existing files
--verbose
Verbose module output
--quiet
Quiet module output

Parameters:

dayofyear=name
Name of the day of year input map
latitude=name
Name of the latitude input map
output=name
Name of the output sunshine hours map

DESCRIPTION

i.sunhours creates a sunshine hours map from any map, it considers a perfect clear day. This method follows Iqbal (1983) as found in the AHAS manual (Parodi, 2000).

The latitude input map can be created with the i.latlong module, or with r.mapcalc's y() function in a latitude-longitude location (possibly reprojected with r.proj.

NOTES

Iqbal, M., 1983. An Introduction to Solar Radiation. Iqbal, M., Editorial: Academic Press. Toronto, Canada. Parodi, G., 2000. AVHRR Hydrological Analysis System. Algorithms and Theory, Version 1.0. WRES - ITC, The Netherlands.

TODO

SEE ALSO

i.evapo.TSA
i.latitude

AUTHORS

Yann Chemin, GRASS Development Team

Last changed: $Date: 2007/02/19 10:19:59 $


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