Average Rainfall Estimation: Methods Performance Comparison in the Brazilian Semi-Arid

Abstract

Considering the rainfall’s importance in hydrological\rmodeling, the objective of this study was the performance comparison, in\rconvergence terms, of techniques often used to estimate the average rainfall\rover an area: Thiessen Polygon (TP) Method; Reciprocal Distance Squared (RDS)\rMethod; Kriging Method (KM) and Multiquadric Equations (ME) Method. The\rcomparison was done indirectly, using GORE and BALANCE index to assess the\rconvergence results from each method by increasing the rain gauges density in a\rregion, through six scenarios. The Coremas/Mae D’água Watershed\remployed as study area, with an area of 8385 km2, is situated\ron Brazilian semi-arid. The results showed the TP, as RDS and ME techniques to\rbe employed successfully to obtain the average rainfall over an area,\rhighlighting the MEM. On the other hand, KM, using two variograms models, had\ran unstable behavior, pointing the prior study of data and variogram’s choice\ras a need to practical applying.