Chuvas urbanas nas capitais do nordeste brasileiro

Abstract

Brazilian Northeast (NEB) has high spatiotemporal variability of rainfall. Some studies were carried out in relation to rainfall in the capitals of NEB, which are summarized in specific studies or, when in their entirety, it does not cover a period of 60 years. Therefore, the objective of the study is to evaluate the variability of urban rainfall on a multiscale (annual and seasonal) in the capitals of NEB, with emphasis on the identification of the meteorological systems responsible for the occurrence of the seasonality of urban rainfall and the detection of its trends. For this, rainfall data from 1960 to 2020 and descriptive statistics were used in the analysis of El Niño-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (ODP) - (annual) and Boxplot (seasonal). The Mann-Kendall (MK) test was applied to detect rainfall trends in the capitals of NEB, as well as establishing a relational pattern between population growth and rainfall accumulated by decade. In the discussion of the results, the following criterion was adopted: North of the NEB (NNEB) - (MA, PI, CE and RN), East of the NEB (ENEB) - (PB, PE, AL and SE) and South of the NEB (SNEB) – (BA). The results obtained in the study indicate that the variability of multiscale urban rainfall (annual and seasonal) in the capitals of NEB is directly associated with the ENSO phases, whose intensity can vary around the ODP phase, with direct influence on the producing and inhibiting meteorological systems. of rain in NEB. In addition, the anthropic influence cannot be ruled out, since there is a relational pattern of population growth and the variability of decennial rainfall in the capitals of NEB, mainly regarding, the urbanization process, which drastically influences the alteration of urban rainfall regimes in the study period. In this way, it was possible to identify the meteorological systems responsible for the occurrence of the seasonality of urban rainfall and the tendency of rainfall in the capitals of NEB. As well as showing the influence of climate variability modes on rainfall dynamics in the capitals of NEB. Changes in rainfall patterns can lead to water shortages in the near future, periods of prolonged drought will compromise urban agriculture and, especially, decrease investments in the industrial, tourist sector and maintenance of quality of life.