Multifractal analysis of 15-min and daily rainfall from a semi-arid region in Portugal

The temporal structure of rainfall was investigated by means of multifractal analysis of 15-min and daily rainfall, measured with recording and non-recording gauges, over periods of up to 30 years. The data were collected at Vale Formoso, Portugal. Spectral analysis and study of the moments of the rainfall intensity on a range of scales showed that multifractal scaling is present. Empirical exponent functions describing the scaling of the moments of the rainfall intensity were determined for different ranges of time scales. Special attention was given to the discontinuities in the scaling function caused by the divergence of moments and the limited resolution of the measuring devices and data. The description of the empirical scaling functions by a multifractal model based on Levy variables was also investigated. (C) 1999 Elsevier Science B.V. All rights reserved.