Impact of blue spaces on the urban microclimate in different climate zones, daytimes and seasons

A systematic review

authored by

Lukas Fricke, Rupert Legg, Nadja Kabisch

Abstract

The phenomenon of the urban heat island effect requires urban planning adaptation strategies that mitigate heat stress. While the cooling effect of urban green spaces has been well studied, knowledge gaps remain regarding the cooling potential of urban blue spaces. Particularly, how the cooling intensity of an urban blue space is influenced by its features and the context in which it occurs, such as its size, location, and more broadly the local climate and season, requires closer investigation. To address these gaps, we conducted a systematic review of studies exploring the thermal effect of urban blue spaces on the surrounding urban microclimate. We extracted the cooling or heating intensity of urban blue spaces, while considering how season, time of day, climate zone, water body size and methodological approach may influence results. Through analysis of 67 identified articles, we found that the thermal effect of blue spaces varies between seasons and time of day, with daytime temperatures in the surrounding urban climate cooled by 2.6 °C on average and maximum intensities observed during late spring and early summer. While at night-time in the summer, the thermal effect showed an average urban heating intensity of 0.6 °C. These values differ depending on the methodological approach used, with mean daytime cooling intensities varying considerably by method (field measurements: 1.4 °C; remote sensing: 3.4 °C; numerical modelling: 1.7 °C). The thermal effect also differed by climate zone, with results indicating a cooling intensity during the day with higher values in temperate climate zones. At night, both cooling and heating effects were observed in continental and temperate zones. The few studies reporting on water body size indicated a higher cooling intensity with greater size of the water body. These varying cooling or heating characteristics of urban blue spaces suggest they can be utilised in different planning contexts to achieve desired goals, depending on their features, the time and location, making them valuable nature-based solutions aimed at mitigating urban heat.

Organisation(s)

Institute of Physical Geography and Landscape Ecology
Digital Landscape Ecology Group

Type

Review article

Journal

Urban Forestry and Urban Greening

Volume

101

ISSN

1618-8667

Publication date

11.2024

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Forestry, Ecology, Soil Science

Sustainable Development Goals

SDG 11 - Sustainable Cities and Communities, SDG 13 - Climate Action

Electronic version(s)

https://doi.org/10.1016/j.ufug.2024.128528 (Access: Open)