Rain habitual for the climate compared in the cities of Aracaju/SE and Natal/RN, Northeast Brazil

Abstract

Climate variability influences meteorological conditions in cities on a large, mesoscale, and microscale. In the Brazilian Northeast (NEB), a region with different atmospheric systems and distinct climatic dynamics, factors such as latitudinal and coastal positions are crucial for understanding climatic conditions. Thus, monitoring the pattern and habituality of rainfall is especially significant for the management and development of specific urban conditions, especially larger ones, more susceptible to climatic problems. Therefore, the objective of this research is to analyze precipitation variability and identify possible temporal trends in the coastal cities of Aracaju/SE and Natal/RN, Northeast Brazil, in the period 2000-2018. For this, meteorological data on precipitation in the period mentioned from the ERA-Interim model were used. For variability analysis, the data were grouped into monthly and annual accumulated values ​​and subjected to descriptive measurements represented by graphs. After preliminary treatment, the Mann-Kendall statistical trend test was calculated over the time series. The results reveal that, for both cities, the months between January and July showed higher heterogeneity of rainfall data (higher occurrence of outliers) due to the influence mainly of the ITCZ, which acts in the transition from autumn to winter and causes frequent rains, of smaller magnitude. Furthermore, it is worth highlighting the influence of cold fronts, EWD, and breeze circulations. In both cities, there was a tendency towards a decrease in rainfall in the annual accumulation during the period analyzed.