COMPARATIVE ANALYSIS OF RAINFALL IN THE STATE OF PARAÍBA USING POLYNOMIAL REGRESSION MODELS

The State of Paraíba shows high spatial and temporal variability in rainfall distribution. In addition, there are many locations with no information about the precipitation values. Thus, the use of polynomial regression (trend surface) in an attempt to obtain estimates of precipitation can be an alternative to a better understanding of the spatiotemporal variability of this meteorological parameter. Thus, the main objective of this study was to use the method of polynomial regression as a tool to estimate monthly averages of rainfall at known locations (weather and rain gauges stations) and compare them with measured values, in order to verify its accuracy within the region of interest. Monthly precipitation data series from 102 weather stations distributed throughout the State of Paraíba, in the period 1962-2001 have been used. The data showed high spatial variability across the state. The 3^rd and 4^th order polynomial regressions have best fit the observed data and the comparison between measured and estimated precipitation values showed that the months from June to November showed the smallest differences over almost the Paraíba territory. Thus, the method adopted is presented as a promising tool to estimate monthly rainfall in the State of Paraíba.

trend surface; spatial variability; analysis of variance.