Wind decline angle (Heat Stress Overlay): Difference between revisions
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To address this issue, an angle of 45 degrees can be applied to smooth the wind flow, leading to a more accurate representation of the frontal surface and producing more realistic values in wooded areas or parks. | To address this issue, an angle of 45 degrees can be applied to smooth the wind flow, leading to a more accurate representation of the frontal surface and producing more realistic values in wooded areas or parks. | ||
[[File:Wind_dpra.png|350px|thumb|left|DPRA: Wind has full impact (<math>S_{frontal}</math>) on next tree even when distance between them is a single cell.]] | |||
[[File:Wind_dpra.png|350px|thumb|left|DPRA: Wind has full impact (<math>S_{frontal}</math>) on next tree even when distance between them is | |||
[[File:Wind_improved.png|350px|thumb|right|DPRA Improved: Wind impact (<math>S_{frontal}</math>) on next tree is reduced producing more realistic results.]] | [[File:Wind_improved.png|350px|thumb|right|DPRA Improved: Wind impact (<math>S_{frontal}</math>) on next tree is reduced producing more realistic results.]] | ||
<br clear=all> | <br clear=all> | ||
{{article end | {{article end | ||
|notes= | |notes= | ||
* Use a value of 90 to use the original {{Heat DPRA Report}} model. | |||
* Use a value of 45 for improved wind flow around individual polygon trees. | |||
* Note that this value has a minimal impact on large woodland/forest polygons or connecting tree foliage because all trees then become a single entity without space between them. | |||
* See [[Wind_calculation_model_(Heat_Stress_Overlay)#Improved wind model|Wind calculation model]] for more details. | * See [[Wind_calculation_model_(Heat_Stress_Overlay)#Improved wind model|Wind calculation model]] for more details. | ||
|seealso= * [[Wind_calculation_model_(Heat_Stress_Overlay)#Improved wind model|Wind calculation model]] | |seealso= * [[Wind_calculation_model_(Heat_Stress_Overlay)#Improved wind model|Wind calculation model]] | ||
Latest revision as of 12:02, 16 July 2026
| Icon | Attribute | Unit | Range | Description | Default value |
|---|---|---|---|---|---|
| WIND_DECLINE_ANGLE | Degrees | This angle determines how the wind flows down around objects. | 45 |
In the original DPRA Heat stress report, the frontal surface is estimated using simplified tree shapes that are aggregated into large woodland polygons and cannot be used for individual tree polygons.
To address this issue, an angle of 45 degrees can be applied to smooth the wind flow, leading to a more accurate representation of the frontal surface and producing more realistic values in wooded areas or parks.
Notes
- Use a value of 90 to use the original DPRA Heat stress report model.
- Use a value of 45 for improved wind flow around individual polygon trees.
- Note that this value has a minimal impact on large woodland/forest polygons or connecting tree foliage because all trees then become a single entity without space between them.
- See Wind calculation model for more details.
See also
API Endpoints
- Group
- Model attributes
- Daily average radiation • Daily average wind speed • Daily maximum temperature • Daily minimum temperature • Dates • Exclude buildings • Exclude water • Exclude foliage height m • Foliage areas • Hourly humidity • Hourly radiation • Hourly temperature • Max shadow distance • Sun altitude • Sun azimuth • Sun daily motion • Wind direction • Wind speed • Wind decline angle
- Group
- Building attributes
- Bowen ratio • Foliage height • Foliage crown factor • Vegetation fraction
- Terrain attributes
- Bowen ratio • Vegetation fraction
- Area attributes
- Foliage height
- Group
- Prequels
- Building elevation • Foliage height • Terrain elevation
- Related