부산대학교 도서관

The waters of the Paraíba do Sul River supply around 15 million people, most of whom live in metropolitan regions of the state of Rio de Janeiro. Climate change alters its precipitation regime and can cause an increase in the occurrence of extreme hydrological events. Furthermore, the variability of precipitation can result from the combined effects of the surface conditions of the oceans and the variations in the dynamics of atmospheric systems. This work aims to detect possible changes in the climatic extremes of precipitation in the Paraíba do Sul hydrographic basin and to investigate evidences of correlation of these indices with the oceanic oscillations associated with the El Niño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO). Results indicate that the northeast sector of the basin present trends of increase in the total annual precipitation, in the number of very humid days and in the occurrence of extreme events, in a space of time up to five days. The southwest sector, on the other hand, show decreasing trends in total annual precipitation, in the number of very humid days, but with an increase trend in the maximum amount of rainfall on five consecutive days. The central sector has characteristics of a transition zone. The correlation analyzes show that oceanic oscillation indices have a non-significant correlation with most annual extreme precipitation indices, except for La Niña (El Niño), that can increase (decrease) the number of consecutive dry days in the region. Besides, for austral autumn, La Niña (El Niño) can decrease (increase) the precipitation in the basin, and in austral winter, hot (cold) phase of AMO can decrease (increase) the precipitation. For austral spring, two teleconnections were found: hot (cold) phase of PDO can increase (decrease) the precipitation in the southwest region of the basin, and during El Niño (La Niña) years, negative (positive) precipitation anomalies tend to occur in the northeast sector of the basin, while positive (negative) anomalies appear in its southwest region. The wavelet spectrum of precipitation anomaly indicates significant values with low power that could be correlated with ENSO, corroborating the results of seasonal correlations.
Author(s): Mônica Carneiro Alves Senna [sup.1], Gutemberg Borges França [sup.2], Matheus Francisco Pereira [sup.2], Mauricio Soares da Silva [sup.2], Enio Pereira de Souza [sup.3], Ian Cunha D`Amato Viana Dragaud [sup.2], [...]