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 number | GRD_VAPOUR_DEFAULT | default value if no grid has been selected | Minimum: 0.000000 Default: 10.000000 | |
| Default | floating point number | GRD_LINKE_DEFAULT | default value if no grid has been selected | Minimum: 0.000000 Default: 3.000000 | |
| Solar Constant [W/m²] | floating point number | 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: 1 | |
| 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: 2023-10-06 | |
| Last Day | date | DAY_STOP | - | Default: 2023-10-06 | |
| Resolution [d] | integer number | DAYS_STEP | Time step size for a range of days calculation given in days. | Minimum: 1 Default: 5 | |
| Moment [h] | floating point number | 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 number | 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 number | ATMOSPHERE | - | Minimum: 0.000000 Default: 12000.000000 | |
| Barometric Pressure [mbar] | floating point number | PRESSURE | - | Minimum: 0.000000 Default: 1013.000000 | |
| Water Content [cm] | floating point number | 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 number | DUST | Dust factor: 100 ppm (standard) | Minimum: 0.000000 Default: 100.000000 | |
| Lumped Atmospheric Transmittance [Percent] | floating point number | 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 number, 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 number Minimum: 0.000000 Default: 10.000000 -GRD_LINKE:<str> Linke Turbidity Coefficient grid, input, optional -GRD_LINKE_DEFAULT:<double> Default floating point number 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 number 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: 1 -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: 2023-10-07 -DAY_STOP:<date> Last Day date Default: 2023-10-07 -DAYS_STEP:<num> Resolution [d] integer number Minimum: 1 Default: 5 -MOMENT:<double> Moment [h] floating point number 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 number 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 number Minimum: 0.000000 Default: 12000.000000 -PRESSURE:<double> Barometric Pressure [mbar] floating point number Minimum: 0.000000 Default: 1013.000000 -WATER:<double> Water Content [cm] floating point number Minimum: 0.000000 Default: 1.680000 -DUST:<double> Dust [ppm] floating point number Minimum: 0.000000 Default: 100.000000 -LUMPED:<double> Lumped Atmospheric Transmittance [Percent] floating point number Minimum: 0.000000 Maximum: 100.000000 Default: 70.000000