The current urban heat island effect over Hong Kong

Abstract

In this study, the current Urban Heat Island (UHI) effect is analyzed by using the Landsat 8 data on 9th August, 2013 (0300 UT) and the split-window (SW) algorithm to retrieve the Land Surface Temperature (LST) over Hong Kong. Comparison of the UHI effect in 2013 and 2005 were also carried out to find out the trends and changes of the built-up areas. The methodology of data collection and production were processed by the use of remote sensing technology, image processing and geographical information system. The two different set of images that were used to create meaningful thermal results in order to analysis and measure the LST were acquired from Operation Land Imager (OLI) and Thermal Infrared sensor (TIR) of Landsat 8. The normalized difference vegetation index (NDVI) was used to investigate the relationship between rural-urban and LST. The in-situ ambient air temperatures measured by the five selected local weather stations were also compared with the LST. The results significantly show that the existence of severe UHI effect in Hong Kong are mainly located in the Kowloon Peninsula, the northern part of Hong Kong Island and the Hong Kong International Airport. Besides, the high LST over the western part of New Territories with scattered development were also shown. The difference of temperature gradients of the in-situ ambient air temperatures and the LST, as well the NDVI confirmed that the UHI is highly dependent on the types of surface materials in the urban and rural areas. Additionally, results point out that the areas showing the increased temperature over the urbanized regions has increased from 2005 to 2013. Analysis also highlighted how urban park can minimize the UHI with compare to the artificial building materials. As a result, urban design and the UHI reduction and mitigation strategies play a very crucial role on the sustainable development of a city.