Analysis of extreme rainfall events on a sub-daily scale in Northeast of Brazil

Given the complex climate of the Brazilian Northeast, its variable rainfall regime in spatial and temporal scales due to multiple geographic factors and the action of various atmospheric systems, as well as intense precipitation events becoming increasingly present and strong, are incipient the initiatives to analyze extreme rainfall on a sub-daily scale. Thus, characterizing the spatial and temporal distribution of IPESS on the NEB, analyzing the seasonality of the number of events for each location and the influence of interannual variability in the occurrence of these events, became the objective of that work. For this, hourly precipitation observations were collected from 119 automatic surface weather stations spread across the NEB, between 2009 and 2018. The night period presented the highest amounts of IPESS. The meteorological stations Ibimirim/PE and Ilhéus/BA had the highest and lowest number of occurrences, respectively. The amplitude of the values of Q presented the thresholds of the stations with the values of 3.4 mm as a minimum, and 28.6 mm as a maximum, referring to the stations of Petrolina/PE and São Luís/MA, respectively. Among the capitals, Teresina/PI had the highest number of EPIES, as well as João Pessoa/PB the lowest, not only among the capitals, but also the second with the lowest number in general. It was observed that during 2009 the events were more frequent, while 2012 presented the smallest amounts.