“…For the data imputing procedure, the technique proposed by Harrell (2001) based on counting the percentages (%) of missing data was adopted, which follows the following criteria: After counting the gaps, the package "mtsdi" version 0.3.5 was used (Junger and Ponce de Leon, 2018) for imputing the data, starting with criterion 2. Data imputing was based on the spline function in order to smooth the time series (Gois et al, 2019), where library = library of the package used; a = number of interactions for F I G U R E 1 Distribution of the environmental mesoregions of the State of Alagoas and location of the 54 weather stations T A B L E 1 Rainfall stations of the State of Alagoas, Brazil, with identifiers (ID), municipalities, longitude ( ), latitude ( ), and altitude (m), and missing data (MD, in %), respectively monthly rainfall (mm); f = empirical function of the monthly rainfall variable (mm); and method = imputing method using the spline. After the organization, manipulation, and application of the imputing method in the monthly rainfall data, the next step was to extract the SPI data for characterizing droughts in the State of Alagoas, obtained from the use of the DrinC Software.…”