Abstract

CASTANEDA, M  and  GONZALEZ, M. Statistical analysis of the precipitation trends in the Patagonia region in southern South America. Atmósfera [online]. 2008, vol.21, n.3, pp.303-317. ISSN 0187-6236.

This paper describes the rainfall climatology in Argentinean Patagonia and faces with rainfall trends. Gridded precipitation dataset from Delaware University is used as an alternative data and they seem to reflect the same patterns that the observed ones. The mean annual precipitation shows maximum amplitude in Patagonia, winter values greater than in summer in the northwest, especially in the west and over the Andes. Both, principal component analysis (PCA) applied to the monthly anomalous precipitations and linear annual rainfall trends, show positive trends in north and south of Patagonia, meanwhile precipitation tends to decrease in the western and central zone. An alternative nonlinear methodology, a piecewise linear function, is used to detect a number of breakpoints in order to identify the moments at which the tendency changes its behavior. Northeast of the Patagonia region and a small zone to the Southeast of Santa Cruz experienced a change in the annual tendencies of precipitation later to the decade of 1960. To the northwest, a vast region denotes a change in precipitation in the 1970 decade, whereas in the environment of the Peninsula of Valdez, the decade of 1990 is in which the change seems to predominate.

Keywords : Precipitation; nonlinear analysis; principal components.

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