DESCRIPTION

r.sun.hourly is a convenient script for running r.sun for multiple times in a loop. It corresponds to mode 1 (instant mode, see r.sun manual page).

Output parameters explanation

Output is one or more series of irradiance raster maps. If flag b is checked the output is a series of binary maps. Using this flag in combination with beam_rad_basename is a convenient way to determine if there is direct sunlight or not at a certain place and time.

Series of maps are (if flag t is checked) registered to space time raster dataset with absolute time and point time (not interval time). Option year has to be specified so that the raster maps can be registered to space time dataset or assigned a timestamp. The reason is that it is not possible to assign time without date.

For GRASS 6, only timestamp is assigned.

EXAMPLES

Calculate for current region the beam irradiance (direct radiation) for DOY 355 in 2014 from 8am to 3pm: 
g.region -p
r.sun.hourly elevation=elevation start_time=8 end_time=15 \
              day=355 year=2014 beam_rad_basename=beam nprocs=4 -t
# show information about newly created space time dataset
t.info beam

# show raster maps registered in beam temporal dataset
t.rast.list beam

NOTE

Beam irradiance binary raster maps can be displayed as semitransparent over other map layers or module r.null can be used to set one of the values (either shade or sunlight) as NULL.

SEE ALSO

r.sun, r.sun.daily in Addons

AUTHOR

Vaclav Petras, NCSU OSGeoREL,
Anna Petrasova, NCSU OSGeoREL

Last changed: $Date$