Multifractal Metrics of Inter-annual and Decadal Variability in Global Precipitation

Multifractal Detrended Fluctuation Analysis (MFDFA) of GPCP precipitation between 1979 and 2017 was conducted to obtain the multifractal spectra of the spatial distribution of zonal monthly precipitation. In addition, CMIP5 simulations as well as TRMM-GPM precipitation products were also analyzed. The results confirm the multifractal behavior of precipitation at global scales with multifractral spectra that display strong seasonality at high and mid-latitudes, and capture the seasonal shifts in the ITCZ as well as symmetries between the northern and southern hemisphere. Global analysis of temporal evolution of the annual cycle of the width of the multifractal spectra, a measure of process complexity and this context interpreted as a proxy of intensity, shows stronger seasonality at low and high latitudes than at mid-latitudes in the southern hemisphere with substantial weakening after themed-1980's at mid and high-latitudes. Whereas no significant changes are noted at mid-and low latitudes, there is a steep re-intensification at high latitudes in the austral winter since the early 2000's consistent with observed changes in the structure of southern Hemisphere large-scale circulation.