Variabilidade da precipitação e os desastres naturais da cidade de João Pessoa - PB, para o recorte temporal de 1991 á 2020.

Abstract

Aware of the importance of a more detailed analysis of rainfall and in view of its contribution to the planning and mitigation of many activities and impacts caused by intense or extreme rainfall, the objective of this study was to analyze the variability of precipitation on annual, monthly, daily and hourly scales of João Pessoa-PB to characterize the rainfall regime, performing the rainfall classification according to the Percentile Technique, employing the Rainfall Anomaly Index (RAI), in order to better identify the intensity of dry and wet periods for the historical series of precipitation, analyze the dynamics of the daily cycle of precipitation with emphasis on the classification of rainfall events and investigate the atmospheric systems that influenced and the risks of disasters related to these rains. The study period is from 1991 to 2020. The Percentile Technique allowed the determination of the rainfall classes of the annual rainfall, which characterized the annual totals in five classes: Very Dry (VD), Dry (D), Normal (N), Rainy (R) and Very Rainy (VR). This classification was analyzed together with periods in which La Niña (LN) and El Niño (EN) occurred and the results did not show the influence of these phenomena on the variability of rainfall in João Pessoa. The same technique was applied to daily data enabling the identification of extreme rainfall events with a daily value equal to or greater than 54 mm. With the 97th percentile 177 extreme rainfall events were identified, the Synoptic Surface Charts made available by CPTEC-INPE were used in order to identify the atmospheric systems that generated the extreme rainfall episodes. The RAI allowed the identification of positive and negative anomalies in the months under study, resulting in 151 months (+) and 209 months (-), with most months under study having precipitation lower than the monthly average of the series under study. In the hourly cycle of precipitation, the period between late evening and early morning presents its maximum frequency, the city of João Pessoa. Therefore, we emphasize the importance of understanding the behavior of precipitation, to help in the generation of subsidies to planners and decision makers, regarding the understanding of extreme rainfall events and their consequences that affect society and thus contribute to a better organization of the urban environment of João Pessoa.