Table 1.
Summary of studies investigating the cooling effect of a group of UGSs.
| Ref | Location (Köppen and Geiger Climatic classification, Kottek et al., 2006) | Month | Green site & comparator | Features of green site | Size | Purpose | Methods/Instruments | Conclusion | |
|---|---|---|---|---|---|---|---|---|---|
| Cao et al. (2010) | Nagoya, Japan (Cfa) | May 25, July 10, October 30 | 92 parks compared with the surrounding area | Trees, grass, shrubs, soil, water, low albedo surfaces, high albedo surfaces | 0.1ha to 41.9 ha | Identifying the role of park parameters (e.g., park size, land-use types, and shapes) in the PCI phenomenon |
|
Cooling effects rely on the park characteristics and seasonal radiation conditions. Also, trees, shrubs and compactness of park benefit the PCI in spring and summer. | |
| Du et al. (2017) | Shanghai, China (Cfa) | February | 68 green spaces | Including trees and shrubs, lawn, different buildings and water body | 1.12 ha to 205.32 ha | Indicating the role of UGS for implementing cooling effect and distinguishing efficient relevant elements in CEI and CED |
|
GCI impacts are contingent upon green space itself and its surrounding features. Furthermore, raising vegetation and water body fractions or reducing impervious surfaces helps to improve GCI impacts. | |
| Lin et al. (2015) | Beijing, China (Dwa) | September 22 | 30 parks compared to city center | Trees and shrubs | 18.42 km2 in total | Developing an alternative method for calculating the cooling extent of green parks by using remote sensing |
|
The area around a park that benefits from the cooling effect increases with park size. | |
| Yu et al. (2017) | Fuzhou, China (Cfa) | From January to July | 435 green patches (connected, and disconnected with water bodies) | 329 patches: tree-based (280) and grassland-based (49) | 0.02 ha to 296.7 ha | Quantifying which form of greenspace has the greatest cooling effect: simple or complex shape, large or small areas |
|
Compact greenspaces in the shape of a circle or square provide significant cooling effects in terms of intensity and efficiency | |
| Feyisa et al. (2014) | Addis Ababa, Ethiopia (Cwb) | October 4–18 | 21 green areas: public parks, green spaces around building and private parks. | Green areas with dense tree vegetation (canopy cover of at least 60%) | 0.85–22.3 ha | Identifying the physical characteristics of USG which determine cooling efficiency and examining its extent of extension |
|
Appropriate choice of species, geometry and size of parks may improve efficiency of urban cooling | |
| Anjos and Lopes (2017) | Aracaju, Brazil (As) | July 19 to October 10 | UGS around 7 urban climate stations in different parts of the city | Vegetated area: from 2.2% to 53% Water bodies: From 0 to 50% |
Not mentioned | Assessing the UHI and PCI effects based on an urban climatological network |
|
Most UHI and PCI intensities do not develop only in the light winds and clear sky But these factor have remarkable impact | |
| Brown et al. (2015) | Kuala Lumpur, Malaysia (Af); Lahore, Pakistan (Bsh); Alice Springs, Australia (Bwh); Kyoto, Japan (Cfa); Toronto, Canada (Dfb) | 10 years data | Five different zones were compared | Five sites in five different climate zones | Various sizes | Recognizing the effect of microclimate modifications on thermal comfort caused by elements in the landscape |
|
Decreasing air temperatures through a ‘cool island park’ is a moderately effective strategy | |
| Chang and Li (2014) | Taipei, Taiwan (Cfa) | August to September and December to February | 60 urban parks were surveyed and compared with the surrounding area | Trees, shrubs and pavement | Various sizes | Exploring details related to the planning and design of city parks such that they may effectively cool surrounding urban areas |
|
Parks and other open spaces should be designed with less than 50% paved area and at least 30% trees, shrubs, and other shadings. | |
| Chen et al. (2014) | Beijing, China (Dwa) | May 22, July 9, October 13 and November 14 | Measured 6 types of UGS: wood-land, shrub land, grassland, cropland, rivers, lakes | UGS covering 35% of the overall study area | Total size: 6450 ha | Focusing on the effects of spatial patterns of urban green patches on their own surface cooling effect |
|
In addition to patch size, the other elements such as shape, edge or connectivity have cooling effects | |
| Sun and Chen (2017) | Beijing, China (Dwa) | July 5 and July 29 | Five types of UGS: Impervious land (IL), forest land (FL), grass land (GL), water body (WB), and bare land (BL). |
Ringroad 5 of the city | Total size: 108.86 km2 | Investigating the dominant combinations of landscape conversions (2012), and quantifying the change of mean LST |
|
Greater focus on protecting natural forests in cities might provide greater benefits for climate mitigation. | |
| Buyadi et al. (Dec 2013) | Shah-Alam, Malaysia (Af) | February 21 and January 21 | Study site situated in center of the city with various kind of land use and green spaces | Water bodies, high dense trees, mixed vegetation | Total size: 8530 ha | Surveying the influence of development on UGS and UHI |
|
Decreasing the vegetation land cover in open spaces has a direct correlation to increasing UHI | |
| Li et al. (2013a,b) | Beijing, China (Dwa) | September 8 and October 4 | Seven landscape Metrics, based on easily calculated, interpretable, and little redundancy |
Not mentioned | 0.52 ha to 0.89 ha | Examining the effects of spatial resolution on the relationship between LST and the spatial pattern of greenspace |
|
The relationship between LST and the abundance of greenspace was negative, but with the spatial configuration of UGS varied by spatial resolution | |
| Kong et al. (2014) | Nanjing, China (Cfa) | June 13 | Part of the city includes the urbanized area of Nanjing and part of its suburbs | Impervious surface, water body, agricultural land, forest vegetation, and barren land | Total size: 9200 ha | Investigating the sensitivity of the cooling effect associated with greenspace to changes in scale; |
|
CEI and characteristics formed by greenspace patterns, and increasing vegetation provide cooling effect | |
| Zhang et al. (2014) | Beijing, China (Dwa) | June to August | 6387 green space | Trees, shrubs, grass, tree-shrubs, shrub-grass | Total size: 22,556 ha | Measuring the ecological benefits of the cooling effect associated with the use of green spaces |
|
The cooling effect and the environmental benefits of UGS largely depend on the green space's structure and size | |
| Mariani et al. (2016) | Milan, Italy (Cfb) | 33 years data (1981–2014) | Five metropolitan sites | Different sites in various zones (rural, urban parks, sites located in canyons of the urban plateau, and urban peaks) | Not mentioned | Describing the behavior of the surface energy balance (SEB) and establishing a frequency distribution climatology of the sensible fraction (SF) index |
|
The cooling effect of urban parks can be improved through ameliorating and optimizing single park structure components | |