Estimative of 1:00 pm relative humidity based on 9:00 am and 3:00 pm data, to Parana state, Brazil

Abstract

This research was based on meteorological data from Cambará, Campo Mourão, Cândido de Abreu, Cascavel, Guarapuava, Londrina, Palmas, Paranavaí and Pinhais regions, Paraná State, Brazil. In order to use Monte Alegre Formula it was necessary to develop equations that estimate the values of Relative Humidity at 13:00 h, from the data of 9:00 and 15:00 h, standard times used in meteorological stations of the Brazilian official network. The meteorological variable used were the relative humidity data at 9:00, 13:00 and 15:00 h. The collected data refer to a period of 5 years, from June 1998 to May 2003. Equations to estimate the 13:00 h relative humidity for each region had to be developed. Equations that presented better fits based on the determination coefficients (R2) and the standard error of residues (sy.x) were submitted to covariance analysis. Similar equations were combined, what generated a general equation that estimates relative humidity at 13:00 h (UR13) based on 9:00 (UR09) data and estimates relative humidity at 13:00 h based on 15:00 (UR15) data to Paraná State. The best equation in the first case was UR13 = e (2,72976 + 0,0162192 UR09) and in the second UR13 = 2,451510 UR15 0,796072.