G. Wotling et al., Regionalization of extreme precipitation distribution using the principal components of the topographical environment, J HYDROL, 233(1-4), 2000, pp. 86-101
This paper deals with the regionalization of the extreme rainfall intensiti
es in the volcanic island of Tahiti (French Polynesia), and focuses how the
method automatically takes into account the topographical relief features.
Principal component analysis of a digital elevation model supplies a limit
ed set of variables describing the topographical environment. These synthet
ic descriptors are linked to the parameters of the rainfall intensity Gumbe
l distribution by using a stepwise regression adjusted on 20 point-rainfall
records. The model is then applied on a regular 300-points grid node, and
interpolated using a spline function to provide an approximation of the plu
viometric risk all over the island. In the case of the island of Tahiti, th
e relationship between the rainfall parameter distributions and the topogra
phical descriptors is very strong, and the method supplies a direct estimat
ion, in space, of the rainfall statistics through the regression model. Val
idation of the results and comparison with simple kriging interpolation sho
w the relevance of the approach. However, more data are needed for a better
confidence in the parameter estimation in some areas of the island. This a
utomatic and objective method could be applied in any mountainous area, whe
re topography has a major influence on the precipitation features, to chara
cterize the non-stationarity of point-rainfall statistics in space. (C) 200
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