TY - JOUR

T1 - Impact of blue spaces on the urban microclimate in different climate zones, daytimes and seasons

T2 - A systematic review

AU - Fricke, Lukas

AU - Legg, Rupert

AU - Kabisch, Nadja

N1 - Publisher Copyright: © 2024 The Authors

PY - 2024/11

Y1 - 2024/11

N2 - 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.

AB - 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.

KW - Climate change

KW - Urban blue space

KW - Urban cooling

KW - Urban heat

KW - Urban microclimate

KW - Urban planning

UR - http://www.scopus.com/inward/record.url?scp=85205678604&partnerID=8YFLogxK

U2 - 10.1016/j.ufug.2024.128528

DO - 10.1016/j.ufug.2024.128528

M3 - Review article

AN - SCOPUS:85205678604

VL - 101

JO - Urban Forestry and Urban Greening

JF - Urban Forestry and Urban Greening

SN - 1618-8667

M1 - 128528

ER -