Evapotranspiração de referência no contexto das mudanças climáticas no estado da Paraíba.

Abstract

Changes in climatic conditions have important implications for arid and semi-arid regions, such as the Brazilian Northeast, which may affect water demand in particular. To evaluate these changes, daily data of wind velocity at 2 meters height, maximum temperature, minimum temperature, average relative humidity and daily sunshine were used, these being the main variables responsible for the increase of reference evapotranspiration - ETo. The units of study are the localities of São Gonçalo, Patos, Monteiro, Campina Grande, Areia and João Pessoa. It was considered a period of approximately 18,250 days with daily data from 1966 to 2016, obtained in the conventional stations of the National Institute of Meteorology (INMET), distributed in the state of Paraíba. The aforementioned data were used to calculate the ETo values and to perform the trend analysis for the climatic variables and the ETo on the annual and seasonal scale. The methodology adopted was to verify the consistency of the meteorological data, which resulted in the comparison of different statistical methodologies that use multivariate techniques to fill in daily meteorological data. The trend analysis was performed using the Mann-Kendall non- parametric test and the change point determination using the Sen slope estimator. The FAO-Penman-Monteith method was used to calculate ETo. It was verified that there was a tendency of elevation in the ETo in the annual scale, in the localities of Monteiro, Campina Grande and João Pessoa; already in the seasonal scale all the localities presented tendency of elevation in the ETo in most of the seasons of the year, with exception of Ducks and Sand. The trends became significant from the 1970s and 1980s to the locations of Monteiro, Campina Grande and Joao Pessoa.