Canadian Forest Service Publications

Evaluation of the Canadian Precipitation Analysis (CaPA) to improve forest fire danger rating. 2017. Hanes, C.C.; Jain, P.; Flannigan, M.D.; Fortin, V.; Roy, G. International Journal of Wildland Fire 26: 509-522.

Year: 2017

Issued by: Great Lakes Forestry Centre

Catalog ID: 37414

Language: English

Availability: PDF (request by e-mail)

Available from the Journal's Web site.
DOI: 10.1071/WF16170

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The Fire Weather Index (FWI) System is the basic method of fire danger rating for fire management agencies in Canada. The spatial interpolation of this weather-based system can be difficult in areas where weather stations are sparse. Previous studies have shown that interpolation of precipitation is especially problematic owing to the isolated nature of convective summer storms. Environment and Climate Change Canada (ECCC) has recently developed the Canadian Precipitation Analysis (CaPA), a gridded precipitation product that integrates forecast data, station observations and Doppler radar, to improve precipitation estimates. The objective of the present study was to evaluate whether CaPA is indeed superior to the currently used interpolation method (thin-plate spline), and to assess the impact of the two precipitation estimates on the FWI System for the province o fOntario. Overall, the results showed the CaPA had increased skill in areas of radar coverage. In non-radar areas, where the ECCC station network was much sparser, there were less significant differences between the methods. Precipitation estimates from the CaPA also significantly improved the estimation of the Fine Fuel Moisture Code. Initial Spread Index and FWI in areas of radar coverage, improving estimates of potential fire danger.

Plain Language Summary

The objective was to look at Environment Canada’s Canadian Precipitation Analysis (CaPA) System and compare it to the way fire management agencies in Canada measure and interpolate precipitation. The two precipitation estimations were then compared in the calculation of the Fire Weather Index (FWI) System to determine if there was a significant improvement to fire danger prediction. The CaPA System integrates Doppler radar, weather station data and weather forecast data. The key finding was that in areas of radar coverage the CaPA improves both the estimation of precipitation and FWI system indices and codes. In areas without radar coverage, the CaPA does as well as the current interpolation method, but with fewer weather stations. Integration of the agency fire weather stations into the CaPA product would improve the results in areas without radar. Precipitation is the most problematic to interpolate over the landscape, of all the inputs for the FWI system. Interpolation of the FWI system began in the 1990’s based on CFS research. These findings are the most significant updates to the spatial application of the FWI system since then.