Abstract

NAUMANN, Gustavo; VARGAS, Walter M  and  MINETTI, Juan L. Dry spells in the La Plata basin: Monitoring and trend stability. Drought implication. Meteorologica [online]. 2008, vol.33, n.1-2, pp.65-81. ISSN 1850-468X.

This paper studies the dry spells observed in the La Plata Basin, using daily data supplied by 98 stations during variable periods between 1900-2005. The main purpose of this study was to define dry spells, especially their extreme cases (meteorologi cal droughts), and to consider them on a daily basis. Trends in over different properties of precipitation and dry spells are presented as a general framework  to detect and compare temporal changes in dry states. These trends, estimated by two different methods, show a decrease, especially in the east of the basin during the period 1972-1998.  The study of the coherence of extreme dry spell shows that these phenomena occur in subregions reducing the risk of occurrence of one of these events in the entire basin. Also the extreme dry spell occurrence show a seasonal preference suggesting that there is a slight and complex dependence on the annual cycle of precipitation.  Finally, the occurrence of the 1988 drought was analyzed in a hemispheric scope. The 1988 drought is considered to be the longest dry spell in the basin. Droughts are studied in detail because water deficits translate to Argentinean economic losses of more than $4 billion dollars.

Keywords : Dry spells; Drought; La Plata Basin.

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