Eventos de precipitação intensa na escala subdiária nas capitais do Nordeste do Brasil

Abstract

The intensification and increase in occurrence of extreme precipitation events on a hourly and sub-daily scale is a direct effect of the climate changes, impacting in different sectors, such as agriculture, environment, transportation, energy, tourism, etc. Thus, it is necessary to understand this phenomenon in areas densely populated, for example the Northeast of Brazil (NEB) capitals. In this sense, the present research aims to analyze the intensity and frequency of sub-daily precipitation extremes (EPIES) in the NEB capitals. The meteorological dataset is composed of hourly information of precipitation covering the period from 1 January 2010 to 31 December 2021. This dataset is managed by the National Institute of Meteorology (INMET). For EPIES, firstly the percentage of missing data was determined, then the dataset was separated into wet and dry periods. The quantile technique will be applied in order to evaluate the 95th percentile and for EPIES identification. The method for EPIES identification consists of quantifying the daily 95th and selecting, for those days, the cases in which the precipitation, in one hour, corresponds to a minimum of 50% of 95th. From this, the study agreed between the municipalities of Aracaju and Recife showed greater variability in the annual negotiation. São Luís, on the other hand, presented the largest EPIES on a monthly scale (March and April) and the largest accumulation of EPIES. Thus, the period with the highest accumulation of EPIES was in the months of November to July, mainly between the months of January to June, in which there is the action of important atmospheric systems for the NEB region, with UTCV, EWD, ITCZ, LI and MCC. Among the capitals, the municipalities of Fortaleza, São Luís and Teresina presented the diurnal cycle with greater variability, in the wet and dry period. Furthermore, the diurnal cycle during days with EPIES presents high peaks at the times these events occur.