Spatiotemporal variability of multifractal properties of fineresolution daily gridded rainfall fields over India

Abstract

This study investigated the multifractal characteristics of fine resolution (0.25ox0.25°) daily gridded rainfall fields of India over the period 1901–2013 to examine their spatiotemporal variability. The scaling characterization using Multifractal Detrended Fluctuation Analysis (MFDFA) detected short-term persistency and strong multifractality in the majority of rainfall (over 81%) of the grid points. A detailed exploration on the spatial variability of multifractal properties such as Hurst exponent, spectral width, asymmetry index, Holder exponent are also performed for six rainfall homogenous regions and 34 meteorological subdivisions in India. The results showed that the highest persistence and complexity is noted in the mountainous terrains of northern and northeastern India. The sub-divisional scale analysis showed that the variability of persistence and complexity is the highest in Kerala and lowest at Vidarbha. Further, the evaluation of multifractal properties of rainfall series of pre- and post-1976/77 Pacific climate shift showed an increase in strength of multifractality in 62% grids after the shift. Changes in the status of persistence with respect to 1976/77 is the highest at Uttaranchal subdivision and changes from positive to negative asymmetry was the highest at northwestern (NW) region. Grid points of Peninsular India exhibited least reduction in complexity, multifractality and persistence in the post-1977 period when compared to pre-1977 period.