Using a geographic information system and remotely sensed thermal imagery to investigate frost-prone areas within the Cariboo Forest Region
Date
1997
Authors
Pettersen, Kevin Michael
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Abstract
Frost can be a significant limitation to forest re-growth in the interior areas of British Columbia. Knowledge of frost sensitive ai"eas can facilitate the selection of replanting strategies after harvesting. Technology associated with geographic information systems (GIS) and remote sensing provides new methods to investigate climatic phenomena such as frost. This research uses a GIS to combine selected topographic, forest and soil data variables with remotely sensed nocturnal surface temperatures for five areas within the Cariboo Forest Region (British Columbia, Canada). Nocturnal surface temperatures were measured via airborne thermal imagery taken during a calm, clear night (September 2, 1988). The GIS worked well to combine the spatial information and produce the multivariate spatial databases. Due to the limited statistical capabilities of the GIS, the analysis of the variables was completed using statistical software. Cross-tabulation, ordinary least squares regression, and interval regression were performed on the multivariate data to investigate the influence of the selected variables on surface temperature. Conducting analysis using multivariate databases was an important advantage since they provided additional explanation for specific relationships (e.g. anomalies) between certain variables. Local relative elevation and slope were the only two variables found to have consistent positive relationships with surface temperature for all five selected study areas. In addition, it was found that relative elevation was most influential in one of the study areas which had a substantially higher average slope. Upon further investigation, it was also found that slope was most influential for study areas which had a large difference in relative elevation. Despite certain limitations, this research has demonstrated that greater knowledge with respect to frost research can be gained by using remotely sensed thermal imagery and GIS.