Page 124 - Çevre Şehir İklim İngilizce - Sayı 1

Urban Cold Space Cooling Capacity

Land Cover
The land cover map, Sentinel 2A (Table 1) is created through controlled
classification of surfaces into five groups as water, grass, forest, soil and
impermeable surfaces using a map that arranges red, green and blue stripes
with the “Merge Data Management-Merge Bands” toolbar of the ArcGIS Pro.
Normalized Difference Vegetation Index
Normalized Difference Vegetation Index (NDVI) is widely used as it can
measure the vegetation density in an urban area with a certain resolution.
The index value is used to measure not only the public green spaces in
urban areas, but also the other green elements such as gardens and urban
landscaping. Using Sentinel 2A satellite images, (Table 1) the NDVI regarding
the presence of vegetation is calculated with the following formula (Nemani
and Running, 1989).
NDVI = (NIR − RED)/(NIR + RED)
The NIR in this formula stands for Near Infrared while RED refers to red
reflectance value. The negative values for NDVI are observed on water
surfaces and the positive values that increase up close shows the presence of
vegetation (NASA, 2000).
The Normalized Difference Built-up Index (NDBI)
Landsat OLI 8 satellite images (Table 1) to map the Normalized Difference
Built-up Index (NDBI) as they measure 2D impermeable surfaces. NDBI is
measured with the following formula (Weng and Lu, 2008).
NDBI = (SWIR − NIR)/(SWIR + NIR)
SWIR in this formula stands for Short-wave Infrared Imaging while NIR refers
to Near Infrared Reflectance. Within NDBI, as the Index value gets closer to
one, the density of impermeable surfaces increases. Thus, in NDBI, negative
values are observed in water surfaces and areas of dense vegetation. Moreover,
NDBI values are inversely correlated with the presence of vegetation (Adeyeri
et al, 2017).

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