solarRad: Computes extra-terrestrial solar radiation

In r2dRue: 2d Rain Use Efficience model

Description

solarRad computes the solar radiation received at the top of the Earth's atmosphere on a horizontal surface. This radiation will change during the day and will be different at different latitudes and in different seasons.

Usage

solarRad(img, day)
solarRad12M(img, outFl, ...)

Arguments

img	object of class SpatialGridDataFrame that provided a projection class and a bbox attributes. The nature of the data.frame that contains the attribute data is not relevant. It must be in geographic coordinates.
day	The number of the day (from 1 to 365) to compute extra-terrestrial radiation.
outFl	A list of 12 file names to save the results.
...	Any unmatched parameter will be passed to the writeGDAL routine.

Details

The output is expressed in cal/cm2*day.

This function runs unnoticed within petHgsm, but can be executed manually.

Value

solarRad returns a single image corresponding to the specified day, as a SpatialGridDataFrame class. solarRad12M writes 12 images to disk in the format especified by the GDAL drivername parameter.

Author(s)

Gabriel del Barrio, Marieta SanJuan & Alberto Ruiz

References

Crop evapotranspiration - Guidelines for computing crop water requirements - FAO Irrigation and drainage paper 56

See Also

petHgsm

Examples

#not run
#aux=readGDAL('iberia_mask')
#calc the extraterrestial radiation the 15-agost
#Rad=solarRad(aux,227)
#writeGDAL(Rad,'solarrad_15ago')
#or to calculate and write to disk, the radiation of the twelve months
#RadFileNames=paste('rad',month.abb,sep='')
#solarRad12M(img,RadFileNames)

Example output

Loading required package: rgdal
Loading required package: sp
rgdal: version: 1.2-10, (SVN revision 673)
 Geospatial Data Abstraction Library extensions to R successfully loaded
 Loaded GDAL runtime: GDAL 1.10.1, released 2013/08/26
 Path to GDAL shared files: /usr/share/gdal/1.10
 Loaded PROJ.4 runtime: Rel. 4.8.0, 6 March 2012, [PJ_VERSION: 480]
 Path to PROJ.4 shared files: (autodetected)
WARNING: no proj_defs.dat in PROJ.4 shared files
 Linking to sp version: 1.2-3 
Loading required package: matrixStats

r2dRue documentation built on May 1, 2019, 10:10 p.m.