Análise quantitativa da variabilidade da chuva em João Pessoa/PB, em várias escalas de tempo.

Abstract

The area of interest for this study was João Pessoa, capital of Paraíba, located on the coast of Northeast Brazil. In this study daily (1961-2012) and hourly (2007-2011) rainfall totals observed at the meteorological station of the National Institute of Meteorology (INMET) in João Pessoa- PB were employed. The data were used to study the variability of rainfall on various time scales, investigating the precipitation anomalies in El Niño (EN) and La Niña (LN) years, as well as identifying heavy rainfall events with an emphasis on extreme cases. The results highlight the months from April to July as the period of maxima in the mean monthly precipitation, and in the frequency of rain days and extreme rainfall events. The extreme events were identified by means of the percentile technique, being defined as all daily precipitation total equal or higher than 60 mm (97th percentile). The monthly standardized precipitation deviation (DPP) shows negative and positive values ranging from -1.7 to 3.7. It was observed that negative DPP are more frequent both at the time of El Niño (62.04%) and La Niña (56.37%), which means a decrease in the volume of rainfall. But these results do not confirm a significant evidence of the influence of El Niño and La Niña phenomena on rainfall variability. In the daily cycle, it was evident the importance of the land breeze circulation in the precipitation regime of the city of João Pessoa, since it favors rainfall in late evening up to early morning, with maximum frequency at 6 LT (Local Time).