Determinação de parâmetros de seca e de chuva utilizando o método “RUN” em séries temporais de precipitação no Cariri Ocidental Paraibano.

Abstract

In the hydroclimatological literature many methodologies are used to numerically represent how shocking the climate events were, according to drought/rainfall anomaly indexes. In this work the "RUN" method was used in time series of precipitation, which identifies sequences of values of the analyzed variable, below or above a certain critical limit. Historical rainfall series comprising at least 30 years of consecutive daily data were used for stations located in the Cariri Oriental of Paraíba state, in the municipalities of Barra de Santana, Caraúbas and São João do Cariri, located in the sub-basin of Taperoá, and in Alto Paraíba Region and Médio Paraíba Region, respectively. Precipitation anomalies were calculated for each data series and the positive and negative areas were identified in relation to the historical average. Consequently, the parameters of duration, severity and intensity in the rainy and drought periods were calculated. The analysis of the database and the graphs of rain/drought duration versus severity and intensity provided several results, mainly: few occurrences with precipitation above the historical average in the three series analyzed; in Bodocongó station, Barra de Santana municipality, the longest periods of drought and lower rainfall intensities were observed; more than 70% of the rainfall, from the Caraúbas and São João do Cariri series, were below the historical average. The methodology aims to support the prognosis of more expressive events of floods and droughts, contributing to the management of natural resources, especially when using historical series with expressive quality and quantity of data.