As droughts represent the most complex and harmful type of natural disaster, this has been affecting the state of Rio Grande do Norte for many years. The SPEI index is determined for different time scales, with multiple and different characteristics in different climates. Index indices (SPEI) are calculated based on weather data from INMET stations collected from 1950 to 2018. In this study, the SPEI index was associated with multivariate cluster analysis statistics using the K-means method for a definition. homogeneous regions of drought, where 05 groups were identified by microregions of the state. This article aims to identify the types of drought that occur in the state of Rio Grande do Norte through the SPEI index and cluster analysis from 1950 to 2018. according to their classification. It was observed for all groups, and there was a higher incidence of moderate drought, significantly present in all 05 groups. The largest dry class, according to its duration not found in group G4, was already recorded in groups G1 and G5, and in groups G3 and G5, but with shorter duration. Extractions were included in the years

The modeling has stood out for allowing the prediction of the functioning of several natural systems including watersheds, emerging as an alternative to obtain ET evapotranspiration estimates. The present work aimed to evaluate the performance of the SWAT (Soil and Water Assessment Tool) hydrological model, in the simulation of the ET for the Piranhas-Açu river basin (BHRPA), in the Rio Grande do Norte stretch, in the absence of calibration. The basin area information used in the simulation is for topography, using the Digital Elevation Model (MDE) provided by EMBRAPA, Climate Forecast System Reanalysis (CFSR) weather data available from Global Weather Data for SWAT, soil classes and characteristics of use and occupation obtained from the Soil and Land Cover and Land Use Maps of Brazil acquired from the Brazilian Institute of Geography and Statistics-IBGE. To comparation the results of the hydrological simulation, the ET through the water balance (BH) was calculated for locations within the study area. The Nash and Sutcliffe (NSE) coefficient values ranged from satisfactory (0.61) to very good (0.82), from the performance index (c) from good (0.67) to very good (0.81), for all locations a strong correlation index (r) was obtained. The ME and Pbias statistical indices show an underestimation of the simulated ET compared to the calculated one. It was found that the SWAT model used without calibration presented a good performance to simulate ET for BHRPA.

Wind is a weather variable of great importance in many applications. However, a detailed understanding of both temporal and spatial behavior is necessary in order to understand the factors that may interfere with its variability. The methodology used in the present study was based on the application of the multivariate statistical technique based on factor analysis (FA) in order to analyze the wind speed variability in the Paraíba State microregions. The data used to constitute the study are CFSR reanalysis data validated with data observed from six INMET stations covering the period from January 2000 to December 2010. According to the study, it was found that the lowest wind speed values Paraíba occur in the first semester and the highest values were obtained in the second semester. Through Factor Analysis (FA), greater weights were identified in the total variation explained by the first two factors, representing about 100% of the total data variance, where the first factor correlates with a period of lower wind variability for the region. the second with the most variable wind speed range.

Geotecnologias aplicadas à ánalise de parâmetros físico-químicos em águas de poços públicos na zona urbana de Triunfo/PB Geotechnologies applied to the analysis of physical-chemical parameters in public well waters in the urban area of Triumph/PB

Análise de parâmetros físico-químicos do rio pedra comprida na zona urbana do município de Sumé-PB Analysis of physical-chemical parameters of the long stone river in the urban area of the municipality of Sumé-PB