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Wildfire selectivity for land cover type: does size matter ?
Barros, Ana M.G.; Pereira, J.M.C.Previous research has shown that fires burn certain land cover types disproportionally to their abundance. We used quantile regression to study land cover proneness to fire as a function of fire size, under the hypothesis that they are inversely related, for all land cover types. Using five years of fire perimeters, we estimated conditional quantile functions for lower (avoidance) and upper (preference) quantil...
A test for directional-linear independence, with applications to wildfire orien...
GarcÃa-Portugués, Eduardo; Barros, Ana M.G.; Crujeiras, Rosa M.; González-Manteiga, Wenceslao; Pereira, J.M.C.Original Paper ; A nonparametric test for assessing the independence between a directional random variable (circular or spherical, as particular cases) and a linear one is proposed in this paper. The statistic is based on the squared distance between nonparametric kernel density estimates and its calibration is done by a permutation approach. The size and power characteristics of various variants of the test a...
Spatial characterization of wildfire orientation patterns in California
Barros, Ana M.G.; Pereira, J.M.C.; Moritz, Max A.; Stephens, Scott L.Using 100 years of fire perimeter maps, we investigate the existence of geographical patterns in fire orientation across California. We computed fire perimeter orientation, at the watershed level, using principal component analysis. Circular statistics were used to test for the existence of preferential fire perimeter orientations. Where perimeters displayed preferential orientation, we searched for evidence of...
Identifying geographical patterns of wildfire orientation: a watershed-based an...
Barros, Ana M.G.; Pereira, J.M.C.; Lund, Ulric J.We searched for geographical patterns in the orientation of wildfires, using watersheds as spatial support for the analysis. An 1975–2005 annual fire atlas of mainland Portugal was used to compute the orientation of fire perimeters and watersheds, using principal component analysis. Circular statistics were employed to test for the existence of a preferred, as opposed to random, mean fire orientation in each ...
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