Abstract

VENTURINI, Virginia  and  KREPPER, Carlos. Characterization of the spatial and temporal distribution of precipitation in the La Plata River Basin. Tecnol. cienc. agua [online]. 2017, vol.8, n.6, pp.63-75.  Epub Aug 06, 2021. ISSN 2007-2422.  https://doi.org/10.24850/j-tyca-2017-06-05.

The La Plata River Basin (LPB) has been undergoing changes in rainfall and river flows ever since 1960. Furthermore, unusual changes have been found from analyzing the low-frequency behavior of an averaged, standardized rainfall series throughout the basin. Three different periods were identified: the first between 1901 and 1959, with a slight positive linear trend; the second between 1960 and 1983 with a notable positive trend; and the last period, after January 1984, with a negative trend. These results have been verified in different rivers in the LPB by temporal flow series. Since the LPB is large, the spatial variations in the standardized rainfall trends were analyzed. This analysis was performed for the three periods mentioned above. Given that these temporal variations undoubtedly affect the recurrence of extreme events, the annual Standardized Precipitation Index (SPI) was used to study those events. Therefore, the spatial distribution of the main components in the SPI [12] series were analyzed. The results show various regions having characteristics that are different than hydrological sub-basins that are delineated by traditional means. While these regions are affected by different phenomena, the ENSO effect is present throughout most of the basin.

Keywords : La Plata Basin; SPI; precipitation; climatic signals.