rsaga.solar.radiation: Potential incoming solar radiation

Description

This function calculates the potential incoming solar radiation in an area either using a lumped atmospheric transmittance model or estimating it based on water and dust content. Use rsaga.pisr() instead with SAGA GIS 2.0.6+.

Usage

rsaga.solar.radiation(
  in.dem,
  out.grid,
  out.duration,
  latitude,
  unit = c("kWh/m2", "J/m2"),
  solconst = 1367,
  method = c("lumped", "components"),
  transmittance = 70,
  pressure = 1013,
  water.content = 1.68,
  dust = 100,
  time.range = c(0, 24),
  time.step = 1,
  days = list(day = 21, month = 3),
  day.step = 5,
  env = rsaga.env(),
  ...
)

Arguments

in.dem: name of input digital elevation model (DEM) grid in SAGA grid format (default extension: .sgrd)
out.grid: output grid file for potential incoming solar radiation sums
out.duration: Optional output grid file for duration of insolation
latitude: Geographical latitude in degree North (negative values indicate southern hemisphere)
unit: unit of the out.grid output: "kWh/m2" (default) or "J/m2"
solconst: solar constant, defaults to 1367 W/m2
method: specifies how the atmospheric components should be accounted for: either based on a lumped atmospheric transmittance as specified by argument transmittance ("lumped", or numeric code 0; default); or by calculating the components corresponding to water and dust ("components", code 1)
transmittance: transmittance of the atmosphere in percent; usually between 60 (humid areas) and 80 percent (deserts)
pressure: atmospheric pressure in mbar
water.content: water content of a vertical slice of the atmosphere in cm: between 1.5 and 1.7cm, average 1.68cm (default)
dust: dust factor in ppm; defaults to 100ppm
time.range: numeric vector of length 2: time span (hours of the day) for numerical integration
time.step: time step in hours for numerical integration
days: either a list with components day and month specifying a single day of the year for radiation modeling; OR a numeric vector of length 2 specifying the start and end date (see Note below)
day.step: if days indicates a range of days, this specifies the time step (number of days) for calculating the incoming solar radiation
env: RSAGA geoprocessing environment obtained with rsaga.env(); this argument is required for version control (see Note)
...: optional arguments to be passed to rsaga.geoprocessor()

Author

Alexander Brenning (R interface), Olaf Conrad (SAGA module)

References

Wilson, J.P., Gallant, J.C. (eds.), 2000: Terrain analysis - principles and applications. New York, John Wiley & Sons.

Examples

Run this code

if (FALSE) {
# potential solar radiation on Nov 7 in Southern Ontario...
rsaga.solar.radiation("dem","solrad","soldur",latitude=43,
    days=list(day=7,month=11),time.step=0.5)
}