Scaling Characteristics of Precipitation Data over Texas

The question addressed in this study was: do the number and magnitude of dry and wet spells occur in a scale invariant manner in the state of Texas or not? To answer this question, a large set of monthly precipitation data from 75 grid points spread across Texas was employed to investigate the spatial variability in the scaling properties of number and magnitude of dry and wet spells. No coherent regional differences were found. Using a power-law analysis, time-scale properties of dry and wet spells were examined, and power-law coefficients were related to the various truncation levels. A linear relationship was found between fractal dimensions of the numbers of dry and wet spells, whereas power-law coefficients of the magnitude remained constant for all truncation levels. Also, significant low-frequency patterns of precipitation were found when the wavelet transform was used. Generally, interannual cycles were found to be significant for the state of Texas. Low-frequency cycles had no distinguishable impacts on the grid point precipitation values where significant deviations from the power law occurred.