Wind Effect (Windward / Leeward Index)
- Author: J.Boehner, A.Ringeler (c) 2008, O.Conrad (c) 2011
- Menu: Terrain Analysis | Climate and Weather
Description
The 'Wind Effect' is a dimensionless index. Values below 1 indicate wind shadowed areas whereas values above 1 indicate areas exposed to wind, all with regard to the specified wind direction. Wind direction, i.e. the direction into which the wind blows, might be either constant or variying in space, if a wind direction grid is supplied.
References
- Boehner, J., & Antonic, O. (2009): Land-surface parameters specific to topo-climatology. In: Hengl, T., & Reuter, H. (Eds.): Geomorphometry - Concepts, Software, Applications. Developments in Soil Science, Volume 33, p.195-226, Elsevier. doi:10.1016/S0166-2481(08)00008-1.
- Gerlitz, L., Conrad, O., B__hner, J. (2015): Large scale atmospheric forcing and topographic modification of precipitation rates over High Asia ___ a neural network based approach. Earth System Dynamics, 6, 1-21. doi:10.5194/esd-6-61-2015.
Parameters
| | Name | Type | Identifier | Description | Constraints |
|---|
| Input | Elevation | grid, input | DEM | - | - |
| Wind Direction | grid, input, optional | DIR | Direction into which the wind blows, starting with 0 for North and increasing clockwise. | - |
| Wind Speed | grid, input, optional | LEN | - | - |
| Output | Wind Effect | grid, output | EFFECT | - | - |
| Effective Air Flow Heights | grid, output, optional | AFH | - | - |
| Options | Grid System | grid system | PARAMETERS_GRID_SYSTEM | - | - |
| Wind Direction Units | choice | DIR_UNITS | - | Available Choices:
[0] radians
[1] degree
Default: 0 |
| Scaling | floating point number | LEN_SCALE | - | Default: 1.000000 |
| Search Distance [km] | floating point number | MAXDIST | - | Minimum: 0.000000
Default: 300.000000 |
| Constant Wind Direction | floating point number | DIR_CONST | constant direction into the wind blows, given as degree | Default: 135.000000 |
| Old Version | boolean | OLDVER | use old version for constant wind direction (no acceleration and averaging option) | Default: 0 |
| Acceleration | floating point number | ACCEL | - | Minimum: 1.000000
Default: 1.500000 |
| Elevation Averaging | boolean | PYRAMIDS | use more averaged elevations when looking at increasing distances | Default: 0 |
Command Line
Usage: saga_cmd ta_morphometry 15 [-DEM ] [-DIR ] [-DIR_UNITS ] [-LEN ] [-LEN_SCALE ] [-EFFECT ] [-AFH ] [-MAXDIST ] [-DIR_CONST ] [-OLDVER ] [-ACCEL ] [-PYRAMIDS ]
-DEM: Elevation
grid, input
-DIR: Wind Direction
grid, input, optional
-DIR_UNITS: Wind Direction Units
choice
Available Choices:
[0] radians
[1] degree
Default: 0
-LEN: Wind Speed
grid, input, optional
-LEN_SCALE: Scaling
floating point number
Default: 1.000000
-EFFECT: Wind Effect
grid, output
-AFH: Effective Air Flow Heights
grid, output, optional
-MAXDIST: Search Distance [km]
floating point number
Minimum: 0.000000
Default: 300.000000
-DIR_CONST: Constant Wind Direction
floating point number
Default: 135.000000
-OLDVER: Old Version
boolean
Default: 0
-ACCEL: Acceleration
floating point number
Minimum: 1.000000
Default: 1.500000
-PYRAMIDS: Elevation Averaging
boolean
Default: 0