Abstract

VELASQUEZ VALLE, Miguel A. et al. Randomness of a series of precipitation in the state of Veracruz, Mexico. Rev. Mex. Cienc. Agríc [online]. 2011, vol.2, n.spe1, pp.41-55. ISSN 2007-0934.

Facing an imminent change in the statistical trends that describe the time series of climate information in the past decades, it is necessary to adequately characterize the time series in order to increase the involved variables' predictability. The aim is to present the analysis of rainfall information considering the fractal analysis in order to explain the degree of randomness of the time series from a multi-scale point of view in time. In the State of Veracruz, the weather station "Las Vigas" is representative of the region known as Las Vigas de Ramírez and is located in the center of the state. The station's length of the time series is 85 years. From this database, daily, decadal, monthly and yearly scale files were generated. These same files are stored as time series with the extension *.ts to calculate the Hurst exponent, using the reference methods of wavelets (H_w) and the rescaled range (H_R/S) designed for the analysis of patterns self-affine with Benoit® commercial program. The Hurst exponent's values were presented for a daily time scale (H_R/S= 0.26 and H_w= 0.22) and average values for the scales of decades (H_R/S= 0.25 and H_w= 0.20), monthly (H_R/S= 0.26 and H_w= 0.09) and annual (H_R/S= 0.24 and H_w= 0.21). Both reference methods indicate anti-persistent behavior of the multi-scalar time series, with a tendency to volatility.

Keywords : anti-persistence; degree of randomness; Hurst exponent; precipitation.