Characterization of Homogeneous Areas of Rainfall in Paraíba and Its Trends

Introduction: Rainfall is an essential element for the life, social activities and development of municipalities in Paraíba, especially those in the semiarid region. A striking characteristic of the rainy season in Paraíba is the spatiotemporal irregularity and high variability of rainfall. This heterogeneity demands scientific investigations that delimit areas of the state with similar rainfall patterns, amidst an irregular distribution. This research aimed to identify and characterize homogeneous areas of precipitation in the state of Paraíba and analyze their trends, contributing to the dissemination of knowledge and to the effective planning of water resources, specifically with regard to precipitation. To carry out the research, 124 rain gauge stations distributed throughout the state were used, with historical series covering the period from January 1994 to December 2022. The data were subjected to analysis of the Local Moran Index and the Ward method, resulting in the identification of 7 homogeneous groups with spatial dependence. The homogeneity of these groups wassubsequently tested using the Mann-Kendall and Pettitt method. The homogeneity tests indicated significant discrepant interannual variability, however the null hypothesis of homogeneity was accepted, revealing that, despite the fluctuations, the groups have homogeneous rainfall patterns. The results obtained are important for the development of accurate predictive models and for the construction of water management strategies in the semiarid region of Paraíba. Objective: The objective of this study is to characterize the areas of rainfall in the state of Paraíba and their trends, with the aim of identifying areas of increasing and decreasing rainfall. Theoretical Framework: Rainfall is an essential element for the life, social activities and development of municipalities in Paraíba, especially those in the semiarid region. One of the characteristics of the rainy season in the localities of Paraíba is the high irregularity and frequency from place to place, making it possible to indicate to the research areas of the state that have similarities amidst an irregular distribution. Method: The methodology adopted for this research involves the analysis of 124 rainfall stations that were subjected to the Moran Local Index survey and the Ward method to identify homogeneous groups with spatial dependence. For trend analyses, homogeneity tests were adopted using the Mann-Kendall and Pettitt method. Results and Discussion: The results obtained revealed that Paraíba has 7 homogeneous groups with discrepant characteristics among neighboring groups and the trend analyses indicate stationarity despite the relevant interannual variability. Research Implications: The practical and theoretical implications of this research are important for water planning in cities in Paraíba, especially those in the semi-arid climate, since the results can serve as support for decision-making regarding water projects, private investments that seek to have water security, and for the general population that aims to cultivate and live in the distinct climates of the state of Paraíba. Originality/Value: This study contributes to the literature through innovative results with the application of trend tests for each homogeneous area, offering support for literary bases for future research that aims to better understand other characteristics of the areas related to rainfall innovations.