Urban Heat Island in Mediterranean Coastal Cities: The Case of Bari (Italy)

Alessandra Martinelli,Dionysia-Denia Kolokotsa,Francesco Fiorito

doi:10.3390/cli8060079

Alessandra Martinelli, Dionysia-Denia Kolokotsa + Show 1 more

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https://doi.org/10.3390/cli8060079

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Abstract

In being aware that some factors (i.e. increasing pollution levels, Urban Heat Island (UHI), extreme climate events) threaten the quality of life in cities, this paper intends to study the Atmospheric UHI phenomenon in Bari, a Mediterranean coastal city in Southern Italy. An experimental investigation at the micro-scale was conducted to study and quantify the UHI effect by considering several spots in the city to understand how the urban and physical characteristics of these areas modify air temperatures and lead to different UHI configurations. Air temperature data provided by fixed weather stations were first compared to assess the UHI distribution and its daily, monthly, seasonal and annual intensity in five years (from 2014 to 2018) to draw local climate information, and then compared with the relevant national standard. The study has shown that urban characteristics are crucial to the way the UHI phenomenon manifests itself. UHI reaches its maximum intensity in summer and during night-time. The areas with higher density (station 2—Local Climate Zone (LCZ) 2) record high values of UHI intensity both during daytime (4.0 °C) and night-time (4.2 °C). Areas with lower density (station 3—LCZ 5) show high values of UHI during daytime (up to 4.8 °C) and lower values of UHI intensity during night-time (up to 2.8 °C). It has also been confirmed that sea breezes—particularly noticeable in the coastal area—can mitigate temperatures and change the configuration of the UHI. Finally, by analysing the frequency distribution of current and future weather scenarios, up to additional 4 °C of increase of urban air temperature is expected, further increasing the current treats to urban liveability.

Highlights

IntroductionThe climate inside cities is heavily influenced by urbanization that radically changes the landscape by replacing open spaces and vegetation with buildings, roads and other infrastructures
The climate inside cities is heavily influenced by urbanization that radically changes the landscape by replacing open spaces and vegetation with buildings, roads and other infrastructures.Materials and characteristics of urban surfaces play a fundamental role in the definition of the local climate, together with anthropogenic heat emissions [1]
The0 fourth one is, instead, located in comparison with the frequency distribution of air temperatures of the 2020 future scenario. This can be recognized as the average Urban Heat Island (UHI) penalty for both stations 2 and 3

Summary

Introduction

The climate inside cities is heavily influenced by urbanization that radically changes the landscape by replacing open spaces and vegetation with buildings, roads and other infrastructures. Materials and characteristics of urban surfaces play a fundamental role in the definition of the local climate, together with anthropogenic heat emissions [1]. The climate inside the cities is different from that of rural areas. The very well-known phenomenon of Urban Heat Island (UHI) causes an increase in temperature in dense portions of the cities (downtown, in particular) [2]. UHI phenomenon has a direct consequence on the increase in buildings’ energy demand [3,4,5], on energy poverty [6,7], and on people’s health, and on liveability of cities [8,9,10].

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