Table-2 shows the comparison of the accumulated heat flux intensity within the urban area delineated with the same area for the 5 cities. In this table, the heat flux intensity of Pyongyang is set as “1” for summer-day, summer-night, winter-day, winter-night, and the intensities for 4 other cities with 4 different season and time are calculated respectively.
Table-2 Comparison of heat flux intensity among the 5 cities
| | Tokyo | Seoul | Pyongyang | Peking | Shanghai |
| Summer/Day time | 107 | 43 | 1 | 52 | 18 |
| Summer/Night time | 70 | 21 | 1 | 10 | 5 |
| Winter/Day time | 59 | 22 | 1 | -1 | 12 |
| Winter/Night time | 1 | -4 | 1 | 35 | 1 |
From this table, the heat flux intensity in Tokyo is most significant among the 5 cites, except the winter-night time. The second significant city is Seoul, however the heat flux intensity of Beijing is most significant in the winter-night time among the 5 cites, and second significant at the summer- day time.
The analysis was made using the single image for the 4 different season/time series(Summer, Winter, Day and Night), therefore, there might exist some reasons excluding the heat island impact, such as geographic, climatic and local characteristics influencing the local heat flux on the day observed by the satellite.
Conclusion
In this study, the land surface temperature was calculated using thermal band with 500m resolution TERRA MODIS data in combination with the visible band data of 250m resolution for 5 major cities in East Asia. And a methodology to indicate the heat flux of urban area to estimate the heat island phenomenon from the satellite images under the different geographic, climatic conditions was used. The method enables the comparison of heat flux of the 5 cities using the MODIS data.
Continuous observation will be made for more quantitative analysis in terms of heat flux as well as the vegetation function to reduce the heat island phenomenon, using long term satellite information which avoids the temporal error such as local climatic condition including the weather of the observation day and time, and sensor anomalies. Furthermore, some more cities from South East Asia such as Bangkok, Hanoi, Hochimin city, Jakarta, Kuala Lumpur, Singapore, covered by Bangkok broadcasting station, will be added for the study.
References
- MODIS Characterization Support Team: MODIS Level 1B Product User’s Guide for Level 1B Version 2.3x Release 2, Internet WEB Page, http://mcstweb.gsfc.nasa.gov/product.html, 2000
- NASA EOS: EOS AM-1 brochure, Internet WEB Page, http://terra.nasa.gov/Publication/AM-1_ brochure.pdf, 2000
- NASA Jet Propulsion Laboratory: ASTER Spectral Library, Internet WEB Page, http://spclib.jpl.nasa.gov, 2000
- MODIS UCSB ICESS: MODIS UCSB Emissivity Library, Internet WEB Page, http://www.icess.ucsb.edu/ modis/EMIS/html/em.html
- (Japanese) Ministry of Environment of Japan, HEAT ISLAND, Internet WEB Page, http://www.env.go.jp/air/report/h13_01.pdf
- Institute of Industrial Science, University of Tokyo, MODIS DB Reception Facility at IIS, Internet WEB Page, http://yasulab.iis.u-tokyo.ac.jp/%7Emodis/index.htm
- Japan Association of Remote Sensing, Remote Sensing Note, p14, 1996