Análise estatística do vento à superfície no Nordeste do Brasil

Abstract

The Northeast region of Brazil (NEB) stands out in the national wind energy production scenario, with 523 wind farms installed out of a total of 619 in Brazil. With winds developed for the production of wind energy mainly in the second half of the year, there is still room for prospecting and expanding wind farms, it should be noted that there are still states with few or no wind farms installed, as is the case of Alagoas. To optimize the choice of the best locations for installing/expanding wind farms, data related to wind, such as predominant direction and speeds at different heights, are increasingly necessary, requiring the most accurate measurements and estimates of this atmospheric variable possible. In this sense, in this work we used wind speed data near the surface from the latest version of a gridded analysis of high spatial resolution (0.1° x 0.1°) on a daily scale, made available by Xavier et al. (2022) from 1961 to 2020. The climatology generated at this high spatial resolution showed that there is an East-West gradient of intensities that amplifies in the Northeast-Southwest direction of the NEB between January and December, with emphasis on the July-December period when it is observed the daily average speed intensities are higher. The north of Maranhão and Piauí, Ceará, with the exception of its extreme south, and large areas of Rio Grande do Norte and other states in the east of the NEB stand out with average daily speeds that exceed 3m/s, in addition to locations in the interior of Pernambuco and Bahia. There is a large area of lowintensity winds throughout the year that encompasses the center-south of the states of Maranhão and Piauí to the west of Bahia. Given this climate scenario, this study is also organized through the application of a multivariate statistical technique, Cluster Analysis (AA), six homogeneous wind regions or groups in the NEB: G1 to G6, following a decreasing order of intensity, which they were delimited by the limits of the municipalities that compose them. G1, for example, is the group with the most intense and constant speeds throughout the year and is located mainly between the states of Rio Grande do Norte and Paraíba, while G6 groups municipalities in the center-south of Maranhão, west of Piauí and west of Bahia. with the lowest wind intensities. These initial results will serve as the basis for complementary studies and projects to expand the generation of electrical energy from wind sources in the NEB. A trend analysis was investigated with the non-parametric Mann-Kendall test, showing that there is a systematic decrease in wind speeds mainly from the beginning of the 2000s, whose structural breaks were identified by the Pettitt test, since this pattern of The increase in average annual wind speed is significant and constant at the end of the time series, especially in the second half of the period between 1991 and 2020.