Remote Sensing of Severe Canadian Tornadoes
The Northern Tornadoes Project (NTP) aims to better detect tornado occurrence throughout Canada, improve severe and extreme weather understanding and prediction, mitigate against harm to people and property, and investigate future implications due to climate change. NTP relies heavily on quasi-daily satellite imagery that captures 4 spectral bands, the visible spectrum in the red, green, and blue (RGB) bands and the near infrared (NI) band at a nominal resolution of 3 meters / pixel, for both operational and research purposes. Operationally, satellite imagery is used in the preliminary detection and characterization of tornado and downburst damage, especially in areas where a ground survey is not possible due to lack of access, such as in the more northern, isolated regions of Canada. For research, NTP is using satellite imagery to systematically search regions across Canada for historical undocumented tornadoes. Due to the lack of population in the northern regions of Canada, it is common for tornadoes in those areas to go unreported, and therefore undocumented. Preliminary results have shown over 150 potential tornadoes found using historical satellite imagery, dating back to 1987. Near infrared imagery from satellites is also being used by NTP to calculate vegetation indices to characterize the damage done to agricultural land by tornadoes and downbursts. Preliminary results have shown that the change in the Normalized Difference Vegetation Index (NDVI) between pre-tornado and post-tornado imagery can be used to characterize features of tornadoes more accurately.