Page 133 - Çevre Şehir İklim İngilizce - Sayı 1

Yasemin Şentürk - Kemal Mert Çubukçu

The results of the study point to a weak correlation in the negative direction
between grass-covered surfaces (GRASS_M) and maximum tree-covered
surface areas. On the other hand, a medium-intensity correlation was observed
in the negative direction with average tree-covered surface areas (T_Av and
Grass_Av). These findings are in line with the result of the previous studies (Kong
et al, 2014, Zhou et al, 2017). This shows that the consistent presence of large
green areas instead of small green areas in a place decreases temperatures
more. As the average green area size increases, the interaction surfaces with
urban environment increases (Cao et al, 2010, Maimaitiyiming et al, 2014, Li
et al, 2017, Zhang et al, 2009). The increase in the interaction surfaces has
resulted in more areas with shade in urban areas and an increase in the heat
transfer between two regions with different temperatures (Maimaitiyiming et
al, 2014, Zhou et al, 2017). However, the maximum green area size was more
effective compared to other variables. This could be related to the fact that
the sample area, İzmir has a lack of green areas with a really big scale. Yet,
previous studies have emphasized that the spatial formation of green areas
in cities may display variations in accounting for the temperature in terms of
cooling intensity and importance (Zhou et al, 2017).
Literature suggests that compared to grass areas, trees are more effective
in terms of cooling effect in public open areas (Ng et al, 2012, Zardo et al,
2017). This results from the shade effect of the trees (Bowler et al, 2010). Yet,
the study results failed to find a significant difference between grass and tree-
covered areas.

2. The Importance of Cool Area Characteristics in the Reduction of
Heat Island Effect

This study reveals that urban green area size (G_S) is quite an important
factor (Table 4) in accounting for the cooling intensity of urban cool areas and
as the green area increases, the cooling capacity of urban cool areas in İzmir
(A_LST and Min_LST) increases as well. The findings are similar to those in
previous studies (Cao et al, 2010; Kong et al, 2014; Lin et al, 2015; Shashau-
Bar and Hoffman, 2010). In literature, Cao et al (2010) emphasized that urban
green area size accounts for 60% of the cooling intensity, but is not enough
on its own. Similarly, Ren et al (2013) measured that urban green area size and
perimeter accounts for the cooling intensity in summer months by %54.66-
%56.22. Similar to the findings in relevant literature, the findings of this study
reveal that out of the variables concerning vegetation and land cover, urban
cool area size (C_S) referring to the characteristics of cool areas, and urban
cool area perimeter (C_P) are the most important variables accounting for
the cooling capacity (Table 4). Additionally, the increase in size and perimeter

118 Journal of Environment, Urbanization and Climate,