dc.description.abstract | Along with the urban development, urban heat island(UHI) effect has
become more serious over Greater Taipei Region(GTR). The enhancement of
UHI effect is mainly due to the increase in the area of artificial impervious
surfaces, and will make the impact on the changes of climate as well as the
regional precipitation. Therefore, it’s important to monitor the phenomenon
of UHI for the metropolis. With the development of spatial information
technology, the remote sensing has advantages of high spectral rate,
multi-scale images, multi-temporal and fast data acquisition. The application
of remote sensing has been focused on urban heat island study nowadays. In
present research, the UHI effect was investigated by means of remote sensing
over GTR.
The observation from Landsat TM/ETM sensors during 1990 to 2009 were
used to analyze the spatiotemporal characteristics of UHI effect for the specific
areas. The retrievals of brightness temperature, Normalized Difference
Vegetable Index(NDVI), land cover type and impervious surface area(ISA) from
TM/ETM data were examined the correlation to the intensity of UHI.
The result indicated that the UHI effect is more severer in summer than the
other seasons(spring and winter) in north Taiwan. The intensity of UHI can be
more than 6℃ in summer. For the effect of land cover type on UHI intensity,
the urban area type can be about 4℃. The results also indicate that the UHI
intensity increased along with the urban development during the past 20 years.
By comparing the land cover and land use changes between 1990 and 2009,
about 11% vegetative area was replaced by the impervious surface over GTR.
In addition, the results showed the good exponential relationship between
ΔISA and ΔUHI, implying that the UHI will be magnified in the areas with large
ISA value efficiently, such as the center of megalopolis.
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