A neural networks-based PMW-IR fusion technique to derive half hourly rainfall estimates at 0.1° resolution

The purpose of this paper is to evaluate a new operational procedure to produce half-hourly rainfall estimates at 0.18 spatial resolution. Rainfall is estimated using a neural networks (NN)–based approach utilizing passive microwave (PMW) and infrared satellite measurements. Several neural networks are tested, from multilayer perceptron to adaptative resonance theory architectures. The NN analytical selection process is explained. Halfhourly rain gauge data over Andalusia, Spain, are used for validation purposes. Several interpolation procedures are tested to transform point to areal measurements, including the maximum entropy estimation method. Rainfall estimations are also compared with Geostationary Operational Environmental Satellite precipitation index and histogram-matching results. Half-hourly rainfall estimates give ;0.6 correlations with PMW data (;0.2 with gauge), and average correlations of up to 0.7 and 0.6 are obtained for 0.58 and 0.18 monthly accumulated estimates, respectively.