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3. Urban Heat Island, Urban Form and Landscape Relation

Urban heat island formation is the most obvious indicator of how changes
in land use and land cover affect the climate on a local and regional scale
(Arnfield, 2003; Yow, 2007; Pielke et al., 2011; Chun and Guldmann, 2014).
Urbanization affects the climate process and also causes rapid changes in
land use and landscape surface characteristics. The replacement of open
spaces, agricultural and forest areas in cities by impermeable surfaces such as
buildings, parking lots and highways leads to a decrease in surface runoff and
an increase in surface temperature (Chapman et al., 2017). This also changes
the albedo and urban geometry compared to rural surfaces. The decrease
in the number of green areas and the increase in impermeable surfaces are
effective factors in increasing temperatures, as they reduce the amount of
evaporation-transpiration and heat flow in urban areas (Oke, 1982; Grimmond
and Oke, 1991). Due to the construction materials used in the structures and
the reflection of radiation from sunlight in the canyon, urban surfaces have
a lower albedo compared to rural areas. Since anthropogenic heat release,
which is the heat released from mand-made activities, is also higher in urban
areas, the formation of urban heat islands is inevitable in these areas (Bonan,
2008; Unger, 2009; Chun and Guldmann, 2014; Chapman et al Tue., 2017). Due
to the fact that the formation of an urban heat island is directly related to the
shape and geometry of cities, urban growth increases the surface temperatures
and the level of heat stress experienced by urban residents. Many studies
have shown that urban form indicators are among the most important factors
affecting urban heat island formation (Stewart, 2011; Heaviside et Dec., 2016;
Ward et al., 2016; Campbell et al., 2018; Liang et al., 2020).
When considering an urban scale, urban size, form, vegetation level
are the components of the urban form that have the major impact on the
thermal environment. It is known that there is a positive relationship between
the size of the city and the urban heat island in the same direction. At the
same time, urban density and socio-economic activities also have strong
positive effects on urban heat island density (Oke, 1973; Estoque et al., 2017;
Takebayashi and Senoo, 2018; Wu, 2010; Debbage and Shepherd, 2015; Zullo
et al., 2019). It is stated that the geometric characteristics of the city have a
greater effect on the formation of urban heat islands than other factors due
to their impacts on the albedo of impermeable surfaces, heat transfer and air
circulation (Debbage and Shepherd, 2015; Morabito et al., 2016; Takebayashi
and Senoo, 2018; Zullo et al., 2019). Formation of heat islands is decreased
due to the cooling effect of heat flow of trees, green spaces as well as urban
vegetation cover. Trees have a refreshing impact on the ground or building
surfaces creating a shade effect. In this way, the formation of heat islands is
also reduced (Zeng et al., 2010; Monteiro et al., 2016; Bonafoni et al., 2017;

322 The Journal of Environment, Urban and Climate