Climate variation in metropolitan cities

Spatial self-containment, contiguity and space-time relations in Cagliari urban area (Sardinia, Italy)

Abstract

Climate has always been studied in cities, where strong relations can be found with urban form and spatial patterns. Temperature variations, heat islands and floods are among the main factors to represent climatic phenomena and related changes over time. The same urban location choices come out from the need to resist adverse events. In general, the urban form can be related to climatic conditions, both to benefit from positive externalities - healthiness, sun exposure, ventilation, water supply - and to reduce negative externalities - thermal stress, heavy rainfall and heat islands. Furthermore, urban development, particularly attributable to land take, put in evidence how the European, and particularly the Italian, urban system presents 56% of population settled in urban areas with a high value of sealed surfaces and limited green areas, so that urban centres are more and more characterizing as climate change hotspots. In this framework the hereby presented research is developed, focused on the observation of the temperature variations in urban areas in time, aimed at capturing the changes occurring also considering the spatial extent and form of the cities more vulnerable to such phenomenon. The research in particular was aimed at exploring possible different ways of aggregating areas to a proper urban dimension: in particular Metropolitan Cities (MC) and Labor Market Area (LMA) in order to identify the most suitable geographical dimension both for the observation of the phenomenon and for the policy targets of climate neutrality. This is done analysing the spatial autocorrelation of climate-related variations in space and time.