Geoscience Reference
In-Depth Information
4 Results and Analysis
The results of this study is presented in four main sub-sections i.e. land use/land
cover maps, land surface temperature distribution, NDVI assessment and evalu-
ation based on the vegetation growth within eighteen years and the transect profiles
(for LST and NDVI) of the detailed study areas.
4.1 Land Use/Land Cover Changes
The land use/land cover maps for the two dates of part of the Petaling District are
shown in Fig.
2
. The total acreage of the study area is 16,904.547 hectares. The
detail acreage of individual land cover of the study area is listed in Table
1
. Over
the period of 18 years, there is significant decrease in the high dense trees (i.e.
forest and agricultural land) land cover category. The total area for the mixed
vegetation category (i.e. crops, parks and bushes) and built-up areas (i.e. com-
mercial, residential and administrative building) increased by 11.24 and 13.63 %
respectively. The cleared land decreased due to its conversion to built-up areas.
Although there is significant increase in built-up areas, the mixed-vegetation area
also increased. This is due to more trees being planted to replace the lost of natural
greenery within the study area.
4.2 Land Surface Temperature
The surface temperature distributions of 1991 and 2009 are shown in Fig.
3
. The
mean temperature for individual land use/land cover is summarized in Table
2
.
Based on Fig.
3
and Table
2
, the lowest and highest radiant temperature for 1991
are 25.8 C (in the high density tree area) and 33.1 C (in the built-up area)
respectively. Meanwhile, for 2009 the radiant temperatures range between 24.0
and 38.0 C. The highest mean temperature is within the built-up area while the
lowest is within water bodies. The implication of urban development by replacing
natural vegetation (forest) to built-up surfaces such as concrete, stone, metal and
asphalt clearly can increase the surface radiant temperature. Although there is
significant increase in the built-up areas, the surface temperature is still relatively
lower (refer to Fig.
3
b). This could be due to the vegetation growth within the
study area. In average, over eighteen years of development, regular matured trees,
green parks, and other vegetation in urban area potentially can reduce urban
temperature and the surrounding areas.
