| Precipitation over arid and hyper-arid regions represents “per se” an extreme event, often
resulting in surface-hydrologic impacts comparatively more catastrophic than in temperate
climates. The spatio-temporal distribution of precipitation through arid climates is in fact
characterized by intense and short-lived patterns and intimately related to the local
availability of water and energy.
However – given the scarcity of data and the limited number of research contributions
analyzing rain extremes in hyper arid environments – is still an open question whether rainfall
sporadically falling on hyper-arid regions, and in particular its convective component,
presents peculiar features connected with the endemically water-limited regime of these
regions. If so, understanding the link between aridity and rainfall variability could turn out a
precious tool to investigate not only the climate of arid regions but also more global trends of
precipitation under global warming and aridification.
In this contribution we analyze the connection between rainfall variability, its temporal
scaling laws and aridity in a climatological prospective. Through a wide dataset of
precipitation time series covering most Continental US (CONUS) we explore the
local dependence of classic intermittency measures on aridity, finding evidence of a
well-defined variability patterns across a wide range of water-limited climates. We also
explore the connection between different intermittency features of arid climates as
contrasted with “wet” regions and briefly discuss the links between clustering,
water-availability thresholds and hydro-climatic extremes. Our findings provide a framework
to better understand the link between intermittency, rainfall scaling and climate in
water-limited regions of the world, with possible extension to global aridification studies. |