rsaga.insolation: Incoming Solar Radiation (Insolation)

Description

This function calculates the amount of incoming solar radiation (insolation) depending on slope, aspect, and atmospheric properties. Module not available in SAGA GIS 2.0.6 and 2.0.7.

Usage

rsaga.insolation(
  in.dem,
  in.vapour,
  in.latitude,
  in.longitude,
  out.direct,
  out.diffuse,
  out.total,
  horizontal = FALSE,
  solconst = 8.164,
  atmosphere = 12000,
  water.vapour.pressure = 10,
  type = c("moment", "day", "range.of.days", "same.moment.range.of.days"),
  time.step = 1,
  day.step = 5,
  days,
  moment,
  latitude,
  bending = FALSE,
  radius = 6366737.96,
  lat.offset = "user",
  lat.ref.user = 0,
  lon.offset = "center",
  lon.ref.user = 0,
  env = rsaga.env(),
  ...
)

Value

The type of object returned depends on the intern argument passed to the rsaga.geoprocessor(). For intern=FALSE it is a numerical error code (0: success), or otherwise (default) a character vector with the module's console output.

Arguments

in.dem: Name of input digital elevation model (DEM) grid in SAGA grid format (default extension: .sgrd)
in.vapour: Optional input: SAGA grid file giving the water vapour pressure in mbar
in.latitude: Optional input: SAGA grid file giving for each pixel the latitude in degree
in.longitude: Optional input: SAGA grid file giving for each pixel the longitude in degree
out.direct: Optional output grid file for direct insolation
out.diffuse: Optional output grid file for diffuse insolation
out.total: Optional output grid file for total insolation, i.e. the sum of direct and diffuse insolation
horizontal: logical; project radiation onto a horizontal surface? (default: FALSE, i.e. use the actual inclined surface as a reference area)
solconst: solar constant in Joule; default: 8.164 J/cm2/min (=1360.7 kWh/m2; the more commonly used solar constant of 1367 kWh/m2 corresponds to 8.202 J/cm2/min)
atmosphere: height of atmosphere in m; default: 12000m
water.vapour.pressure: if no water vapour grid is given, this argument specifies a constant water vapour pressure that is uniform in space; in mbar, default 10 mbar
type: type of time period: "moment" (equivalent: 0) for a single instant, "day" (or 1) for a single day, "range.of.days" (or 2), or "same.moment.range.of.days" (or 3) for the same moment in a range of days; default: "moment"
time.step: time resolution in hours for discretization within a day
day.step: time resolution in days for a range of days
days: numeric vector of length 2, specifying the first and last day of a range of days (for types 2 and 3)
moment: if type="moment" or "same.moment.range.of.days", moment specifies the time of the day (hour between 0 and 24) for which the insolation is to be calculated
latitude: if no in.latitude grid is given, this will specify a fixed geographical latitude for the entire grid
bending: should planetary bending be modeled? (default: FALSE)
radius: planetary radius
lat.offset: latitude relates to grids "bottom"(equivalent code: 0), "center" (1), "top" (2), or "user"-defined reference (default: "user"); in the latter case, lat.ref.user defines the reference
lat.ref.user: if in.latitude is missing and lat.offset="user", then this numeric value defines the latitudinal reference (details??)
lon.offset: local time refers to grid's "left" edge (code 0), "center" (1), "right" edge (2), or a "user"-defined reference.
lon.ref.user: if in.longitude is missing and lon.offset="user", then this numeric value defines the reference of the local time (details??)
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(), including the env RSAGA geoprocessing environment

Author

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

Details