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Harvard Forest Data Archive
EXPOS Model for Estimating Topographic Exposure to WindRelated Publications
- HF024-01: zip file contains Expos program (Windows executable file and related files)
- Lead: Emery Boose
- Contact: Information Manager
- Start date:
- End date:
- Status: completed
- Release date: 1999
- EML file: knb-lter-hfr.24.16
- DOI: digital object identifier
- EDI: data package
- DataONE: data package
- Related links:
- Landscape and Regional Impacts of Hurricanes in New England 1620-1997
- Landscape and Regional Impacts of Hurricanes in Puerto Rico 1508-1997
- Reconstruction of the 1938 Hurricane in New England and Hurricane Hugo in Puerto Rico
- Study type: modeling
- Research topic: ecological informatics and modelling
- LTER core area: disturbance
- Keywords: geographic information systems, hurricane damage, landscape, models, topography, wind
EXPOS is a simple model of topographic exposure to wind that utilizes digital elevation data to predict which points on a landscape are exposed to or protected from a given wind direction. The model was developed to approximate the effects of topography on hurricane wind flow at a landscape scale (~ 10 km).
The model requires an accurate digital elevation map and a specified wind direction. Each point on the elevation map is then classified as protected or exposed, depending on whether or not it falls within the wind shadow cast by points upwind. The wind shadow is estimated by assuming that the wind bends downward no more than a fixed inflection angle from the horizontal as it passes over a height of land. The effects of topographic features beyond the margins of the input elevation map are of course not predicted by the model.
For a given landscape and wind direction, predicted protected areas decrease in size as the inflection angle increases. Application of the model in studies of two recent hurricanes suggests that the probability of wind damage in protected areas also decreases as the inflection angle increases. An inflection angle of about 5 to 10 degrees was found to give good results.
For more information on the EXPOS model, please see the published paper (Boose, E. R., D. R. Foster, and M. Fluet. 1994. Hurricane impacts to tropical and temperate forest landscapes. Ecological Monographs 64: 369-400). Additional information is contained in the documentation that accompanies the program.
Instructions for installing and using the EXPOS program are contained in the accompanying Readme file.
This dataset is released to the public under Creative Commons CC0 1.0 (No Rights Reserved). Please keep the dataset creators informed of any plans to use the dataset. Consultation with the original investigators is strongly encouraged. Publications and data products that make use of the dataset should include proper acknowledgement.
Boose E. 1999. EXPOS Model for Estimating Topographic Exposure to Wind. Harvard Forest Data Archive: HF024 (v.16). Environmental Data Initiative: https://doi.org/10.6073/pasta/b3b62a833070f274cf634121dbef2597.
HF024-01: zip file contains Expos program (Windows executable file and related files)
- Compression: zip
- Format: Windows executable
- Type: model