Exploring some characteristics of the rainfall island in Barcelona

Abstract

In urban areas, rainfall patterns often differ from those in surrounding rural environments, influenced by modified atmospheric circulation, urban heat island (UHI) effects, and pollutant particles acting as condensation nuclei. This study explores the characteristics of the urban rainfall island in Barcelona using high-resolution rainfall data collected every 5 minutes from a dense urban network of about 20 tipping-bucket rain gauges over 25 years (1994–2019). In addition to several rainfall indices established by the Expert Team on Climate Change Detection and Indices (ETCCDI), we analyse the spatial distribution of a simple scaling parameter linked to rainfall irregularity, which reveals a concentric pattern around the city core, gradually decreasing toward the periphery, mirroring the spatial structure of the UHI. Although data from outside the urban area are not available, the internal gradients are sufficient to identify and characterise the urban rainfall island. In contrast, the spatial patterns of the ETCCDI do not exhibit this concentric form; instead, depending on rainfall duration, they highlight other drivers such as local topography and maritime influence.

11 - Ciutats i Comunitats Sostenibles

13 - Acció per al Clima

Postprint (published version)