Aplicação de análises estatísticas na pluviometria das bacias hidrográficas Aguapeí-Peixe (SP)

Abstract

The Southeast region of Brazil is located in an area vulnerable to the occurrence of climate extremes, such as episodes of severe rainfall and flooding. Thus, it is short important the understanding of spatiotemporal variability of these events for the water and energy planning to a certain region. Using varied statistical analyzes, the aim of this study was to detect the oscillations, systems or dominant phenomena that influence the rainfall and the occurrence of extreme events in River Hydrographic Basins Aguapeí-Peixe. In addition, the time series of precipitation were evaluated by applying the Mann-Kendall Test in order to identify climatic trends, in an attempt to verify the most vulnerable areas to climate change, the groups with similar rainfall patterns were detected in order to enrich the climatic understanding of the basins using the Cluster analysis, and also extreme events were accounted in the Basin were counted through the application of Standardized Precipitation Index (SPI). To this study it was used precipitation data of 18 stations in the São Paulo states obtained through the ANA. They were identified the timescales that influence in the precipitation and the occurrence of extreme events in each rainfall station in the basins, the scale of approximately 22 years that is related to the PDO was presented as the dominant scale in all rainfall stations, comparing to the scales of 11 years, 2-7 years and the scale of 0.25-0.5 years. The study revealed the association of different timescales contributes to the increase of the precipitation index, on the other hand, the lack of them is related to the years of low rainfall. The results revealed that there were increasing trends in the precipitations in all the stations analyzed and it indicates that the rains which occurred are gradually increasing along the period and this behavior tends to continue. The dendrogram generated by the Cluster analysis identified the existence of 3 subgroups contained in 2 larger groups within the Basin; the knowledge of homogeneous climatic groups assists in the implementation of water resources management. The SPI results showed a higher frequency of drought events, however, the occurrence of rainy events was more intense. In general, the results obtained through the application of statistical analyzes in the pluviometry of the River Hydrographic Basins Aguapeí-Peixe improve the climate understanding in the region and they contribute to water and energy planning, generating benefits to the economic sector and to the population.