Rainfall intermittency as a hydrological extreme

Abstract

<p>Rainfall intermittency is considered a distinctive feature of the hydrological regime of arid regions. Here, the alternation between prolonged dry spells and extreme precipitation events represents a key environmental control that shapes the landscape, ecosystems, and many aspects of human life.</p> <p>Yet, the alternation between floods and droughts is increasingly becoming a characteristic component of mid-latitude temperate climates and a central feature of hydrological extremes at the global scale.</p> <p>This contribution analyzes the connection between rainfall intermittency, its temporal scaling laws, and aridity from a climatological perspective. Our central assumption is that rainfall intermittency depends on both fine-scale processes – such as land-atmosphere interactions and the local availability of water and energy – and large-scale climatic forcing and represents a primary climatic forcing across a wide range of spatial and temporal scales.</p> <p>Through an extensive data set of hourly precipitation data (NOAA US-HPD) covering most Contiguous US, we explore the link between aridity and different intermittency statistics, finding evidence of a well-defined functional relation between intermittency and aridity measures across a wide range of climates.</p> <p>Our findings provide a framework to better understand future precipitation patterns and trends across a wide range of climates, with major implications for global aridification studies.</p>