A simple scaling analysis of rainfall in Andalusia (Spain) under different precipitation regimes

What is it about?

Being Andalusia a Spanish region of considerable climatic variety, with notably wet areas as well as extremely dry zones, this study has been useful to investigate the relationship between the value of the simple scaling parameter β and the characteristic rainfall regime of a place. Despite the great correspondence with the average annual precipitation (PRCPTOT), a clear dependence on rainfall irregularity can also be observed, this characteristic revealed by the ratio between the maximum daily precipitation and PRCPTOT, as well as by the wet spells frequency index CWD. The spatial distribution of the simple scaling parameter has captured the increasing influence of the Mediterranean Sea towards the East; the easternmost dry areas are clearly influenced by Mediterranean disturbances, with a high proportion of convective rainfall and an irregular rainfall pattern.

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Photo by Imelda on Unsplash

Photo by Imelda on Unsplash

Why is it important?

Using the simple scaling parameter, the generalized equations of the intensity-duration-frequency (IDF) curves, of great hydrological interest, have been calculated for the eight Andalusian provincial capitals. Moreover, the temporal trends of the simple scaling parameter in the four past decades have been studied in the different areas with the aim of determining if changes in their rainfall patterns due to global warming can be detected. The mean value of the scaling parameter β for all Andalusia has shown a decreasing trend over the past 40 years, compatible with a possible increase towards rainfall pattern irregularity for some areas of the region.