Tool Potential Incoming Solar Radiation
Calculation of potential incoming solar radiation (insolation). Times of sunrise/sunset will only be calculated if time span is set to single day.
Most options should do well, but TAPES-G based diffuse irradiance calculation ('Atmospheric Effects' methods 2 and 3) needs further revision!
References
- Böhner, J., Antonić, O. (2009): Land Surface Parameters Specific to Topo-Climatology. In: Hengl, T. & Reuter, H.I. [Eds.]: Geomorphometry - Concepts, Software, Applications.
- Hofierka, J., Šúri, M. (2002): The solar radiation model for Open source GIS: implementation and applications. International GRASS users conference in Trento, Italy, September 2002. ResearchGate.
- Oke, T.R. (1988): Boundary Layer Climates. London, Taylor & Francis.
- Wilson, J.P., Gallant, J.C. (2000): Secondary topographic attributes. In: Wilson, J.P., Gallant, J.C. [Eds.]: Terrain analysis: Principles and applications. New York, John Wiley & Sons, Inc., 87-131. ResearchGate.
- Author: O.Conrad (c) 2010
- Menu: Terrain Analysis|Lighting
Parameters
Name | Type | Identifier | Description | Constraints | |
---|---|---|---|---|---|
Input | Elevation | Grid, input | GRD_DEM | - | - |
Sky View Factor (*) | Grid, input, optional | GRD_SVF | - | - | |
Water Vapour Pressure [mbar] (*) | Grid, input, optional | GRD_VAPOUR | - | - | |
Linke Turbidity Coefficient (*) | Grid, input, optional | GRD_LINKE | - | - | |
Output | Direct Insolation | Grid, output | GRD_DIRECT | - | - |
Diffuse Insolation | Grid, output | GRD_DIFFUS | - | - | |
Total Insolation (*) | Grid, output, optional | GRD_TOTAL | - | - | |
Direct to Diffuse Ratio (*) | Grid, output, optional | GRD_RATIO | - | - | |
Compare to Flat Terrain (*) | Grid, output, optional | GRD_FLAT | - | - | |
Duration of Insolation (*) | Grid, output, optional | GRD_DURATION | - | - | |
Sunrise (*) | Grid, output, optional | GRD_SUNRISE | - | - | |
Sunset (*) | Grid, output, optional | GRD_SUNSET | - | - | |
Options | Grid System | Grid system | PARAMETERS_GRID_SYSTEM | - | - |
Default | Floating point | GRD_VAPOUR_DEFAULT | default value if no grid has been selected | Minimum: 0.000000 Default: 10.000000 | |
Default | Floating point | GRD_LINKE_DEFAULT | default value if no grid has been selected | Minimum: 0.000000 Default: 3.000000 | |
Solar Constant [W/m²] | Floating point | SOLARCONST | - | Minimum: 0.000000 Default: 1367.000000 | |
Local Sky View Factor | Boolean | LOCALSVF | Use sky view factor based on local slope (after Oke 1988), if no sky viev factor grid is given. | Default: 1 | |
Units | Choice | UNITS | Units for output radiation values. | Available Choices: [0] [kWh/m²] [1] [kJ/m²] [2] [J/cm²] Default: 0 | |
Shadow | Choice | SHADOW | Choose 'slim' to trace grid node's shadow, 'fat' to trace the whole cell's shadow, or ignore shadowing effects. The first is slightly faster but might show some artifacts. | Available Choices: [0] slim [1] fat [2] none Default: 0 | |
Location | Choice | LOCATION | - | Available Choices: [0] constant latitude [1] calculate from grid system Default: 0 | |
Latitude | Degree | LATITUDE | - | Minimum: -90.000000 Maximum: 90.000000 Default: 53.000000 | |
Time Period | Choice | PERIOD | - | Available Choices: [0] moment [1] day [2] range of days Default: 1 | |
Day | Date | DAY | - | Default: 2023-07-16 | |
Last Day | Date | DAY_STOP | - | Default: 2023-07-16 | |
Resolution [d] | Integer | DAYS_STEP | Time step size for a range of days calculation given in days. | Minimum: 1 Default: 5 | |
Moment [h] | Floating point | MOMENT | - | Minimum: 0.000000 Maximum: 24.000000 Default: 12.000000 | |
Time Span [h] | Value range | HOUR_RANGE | Time span used for the calculation of daily radiation sums. | - | |
Resolution [h] | Floating point | HOUR_STEP | Time step size for a day's calculation given in hours. | Minimum: 0.000000 Maximum: 24.000000 Default: 0.500000 | |
Atmospheric Effects | Choice | METHOD | - | Available Choices: [0] Height of Atmosphere and Vapour Pressure [1] Air Pressure, Water and Dust Content [2] Lumped Atmospheric Transmittance [3] Hofierka and Šúri Default: 2 | |
Height of Atmosphere [m] | Floating point | ATMOSPHERE | - | Minimum: 0.000000 Default: 12000.000000 | |
Barometric Pressure [mbar] | Floating point | PRESSURE | - | Minimum: 0.000000 Default: 1013.000000 | |
Water Content [cm] | Floating point | WATER | Water content of a vertical slice of atmosphere in cm: 1.5 to 1.7, average=1.68 | Minimum: 0.000000 Default: 1.680000 | |
Dust [ppm] | Floating point | DUST | Dust factor: 100 ppm (standard) | Minimum: 0.000000 Default: 100.000000 | |
Lumped Atmospheric Transmittance [Percent] | Floating point | LUMPED | The transmittance of the atmosphere, usually between 60 and 80 percent. | Minimum: 0.000000 Maximum: 100.000000 Default: 70.000000 | |
Update | Choice, GUI | UPDATE | show direct insolation for each time step. | Available Choices: [0] do not update [1] fit histogram stretch for each time step [2] constant histogram stretch for all time steps Default: 0 | |
Constant Histogram Stretch | Floating point, GUI | UPDATE_STRETCH | - | Minimum: 0.000000 Default: 1.000000 | |
(*) optional |
Command-line
Usage: saga_cmd ta_lighting 2 [-GRD_DEM <str>] [-GRD_SVF <str>] [-GRD_VAPOUR <str>] [-GRD_VAPOUR_DEFAULT <double>] [-GRD_LINKE <str>] [-GRD_LINKE_DEFAULT <double>] [-GRD_DIRECT <str>] [-GRD_DIFFUS <str>] [-GRD_TOTAL <str>] [-GRD_RATIO <str>] [-GRD_FLAT <str>] [-GRD_DURATION <str>] [-GRD_SUNRISE <str>] [-GRD_SUNSET <str>] [-SOLARCONST <double>] [-LOCALSVF <str>] [-UNITS <str>] [-SHADOW <str>] [-LOCATION <str>] [-LATITUDE <double>] [-PERIOD <str>] [-DAY <date>] [-DAY_STOP <date>] [-DAYS_STEP <num>] [-MOMENT <double>] [-HOUR_RANGE_MIN <double>] [-HOUR_RANGE_MAX <double>] [-HOUR_STEP <double>] [-METHOD <str>] [-ATMOSPHERE <double>] [-PRESSURE <double>] [-WATER <double>] [-DUST <double>] [-LUMPED <double>] -GRD_DEM:<str> Elevation Grid, input -GRD_SVF:<str> Sky View Factor Grid, input, optional -GRD_VAPOUR:<str> Water Vapour Pressure [mbar] Grid, input, optional -GRD_VAPOUR_DEFAULT:<double> Default Floating point Minimum: 0.000000 Default: 10.000000 -GRD_LINKE:<str> Linke Turbidity Coefficient Grid, input, optional -GRD_LINKE_DEFAULT:<double> Default Floating point Minimum: 0.000000 Default: 3.000000 -GRD_DIRECT:<str> Direct Insolation Grid, output -GRD_DIFFUS:<str> Diffuse Insolation Grid, output -GRD_TOTAL:<str> Total Insolation Grid, output, optional -GRD_RATIO:<str> Direct to Diffuse Ratio Grid, output, optional -GRD_FLAT:<str> Compare to Flat Terrain Grid, output, optional -GRD_DURATION:<str> Duration of Insolation Grid, output, optional -GRD_SUNRISE:<str> Sunrise Grid, output, optional -GRD_SUNSET:<str> Sunset Grid, output, optional -SOLARCONST:<double> Solar Constant [W/m_] Floating point Minimum: 0.000000 Default: 1367.000000 -LOCALSVF:<str> Local Sky View Factor Boolean Default: 1 -UNITS:<str> Units Choice Available Choices: [0] [kWh/m_] [1] [kJ/m_] [2] [J/cm_] Default: 0 -SHADOW:<str> Shadow Choice Available Choices: [0] slim [1] fat [2] none Default: 0 -LOCATION:<str> Location Choice Available Choices: [0] constant latitude [1] calculate from grid system Default: 0 -LATITUDE:<double> Latitude Degree Minimum: -90.000000 Maximum: 90.000000 Default: 53.000000 -PERIOD:<str> Time Period Choice Available Choices: [0] moment [1] day [2] range of days Default: 1 -DAY:<date> Day Date Default: 2023-07-16 -DAY_STOP:<date> Last Day Date Default: 2023-07-16 -DAYS_STEP:<num> Resolution [d] Integer Minimum: 1 Default: 5 -MOMENT:<double> Moment [h] Floating point Minimum: 0.000000 Maximum: 24.000000 Default: 12.000000 -HOUR_RANGE_MIN:<double> Time Span [h] Value range -HOUR_RANGE_MAX:<double> Time Span [h] Value range -HOUR_STEP:<double> Resolution [h] Floating point Minimum: 0.000000 Maximum: 24.000000 Default: 0.500000 -METHOD:<str> Atmospheric Effects Choice Available Choices: [0] Height of Atmosphere and Vapour Pressure [1] Air Pressure, Water and Dust Content [2] Lumped Atmospheric Transmittance [3] Hofierka and __ri Default: 2 -ATMOSPHERE:<double> Height of Atmosphere [m] Floating point Minimum: 0.000000 Default: 12000.000000 -PRESSURE:<double> Barometric Pressure [mbar] Floating point Minimum: 0.000000 Default: 1013.000000 -WATER:<double> Water Content [cm] Floating point Minimum: 0.000000 Default: 1.680000 -DUST:<double> Dust [ppm] Floating point Minimum: 0.000000 Default: 100.000000 -LUMPED:<double> Lumped Atmospheric Transmittance [Percent] Floating point Minimum: 0.000000 Maximum: 100.000000 Default: 70.000000