rsaga.insolation: Incoming Solar Radiation (Insolation)

In RSAGA: SAGA Geoprocessing and Terrain Analysis

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(),
  ...
)

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

Details

Calculation of incoming solar radiation (insolation). Based on the SADO (System for the Analysis of Discrete Surfaces) routines developed by Boehner & Trachinow.

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.

Note

This function uses module Insolation (code: 3) from SAGA library ta_lighting. It is available in SAGA GIS 2.0.4 and 2.0.5 but not 2.0.6 and 2.0.7; see rsaga.pisr().

Author(s)

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

See Also

rsaga.solar.radiation(), rsaga.pisr(), rsaga.hillshade()

RSAGA documentation built on Dec. 10, 2022, 1:12 a.m.