Estudo das alterações dos elementos meteorológicos no Estado de Pernambuco no período de 1961 a 2000.

Abstract

Temperature and relative humidity of the air, wind velocity and rainfall data of Recife, Pesqucira, Triunfo, Garanhuns, Cabrobo and Pclrolina, which arc located in the Slate of Pernambuco, were utilized to evaluate the temporal changes in the referred meteorological parameters. The data were collected for the period between 1961 and 2000. In the first place, the 40 year data was distributed into four sub-periods of 10 years each (1961-1970, 1971- 1980, 1981-1990 and 1991-2000) and the behavior of the climatic parameters was analyzed for all the locations. Using the normalized deviations and the method of least squares for the period of 1961 to 2000, the tendencies and their regression lines of rainfall, wind velocity, air temperature and relative humidity were evaluated. Harmonic analyses of these meteorological elements was conducted to identify the major important cycles. Results show that there was a decrease of 247,0 mm in the precipitation over the last decade in Recife, this reduction is associated with the two intense episodes of the phenomenon of El Nino during 1993 and 1997/1998. A decrease in relative humidity of about 3,1% was observed during the period of 1991-2000 for the locality of Pesqucira. A global increase of about 0,02° C was noted in the air temperature in the last 40 years. In the last 10 years there were specific cases where air temperature varied between 0,2 0 C and 0,5 0 C. The wind velocities were decreased in certain regions and increased in some regions of the State of Pcrnambuco, characterizing its sensibility to the changes and irregularities in the underlying surface. It is also verified, through the harmonic analysis, that the rainfall, wind velocity, air temperature and relative humidity present periodicities around the harmonic of maximum contribution, influenced by the atmospheric and oceanic phenomenon, characterized in its tendency and independent of its variations.