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Abstract
TERRA /MODIS has 3 different modes of spatial resolution - 250m, 500m and 1000m - with 36 spectral bands in total and it covers the whole region of the earth both in day-time and night-time every day. The combination of spatial, spectral and time resolutions is considered to be more effective to monitor the regional heat environment associated with the land cover than the data of NOAA/AVHRR. The MODIS ground station at University of Tokyo covers the east part of Asia and data have been archived from May, 2001. In this study, major cities in the East Asia such as Tokyo, Seoul, Pyongynag, Peking and Shanghai are picked up for analysis, and the urban heat environments of the cities were monitored using MODIS data. The land cover characterization and the "Heat Island Intensity" were analyzed by comparing the summer images versus the winter images as well as day time images versus night time images. A method to normalize the hear environment of urbanized areas among different cities with different climatic conditions are proposed. The study concluded that the hear flux is most significant in Tokyo and it is about 100 times larger than that of Pyongyan in the summer-day time and 70 times in the summer-night time.
Introduction
The "Heat Island" is expanding for many big cities in the world, and the phenomenon is analyzed in terms of local/regional energy balance, economic activities, climatic aspect and so on. It is discussed as the site-specific issue5), however it is occurring in many places in global scale with different intensity. It seems to be important to analyze the heat island phenomenon among cities in different geographic location to understand the mechanism of it and forecasting the progress of it, because different stages of the heat island are exist and they are developing in different development stages.
The Institute of Industrial Science, University of Tokyo has been receiving NASA's satellite "TERRA/MODIS" data starting from May, 2001 in order to monitor the environment and disaster parameters around the East Asia6). A project was launched to analyze and assess the environment and disasters of main cities in Asia. In order to acquire TERRA data for expanded continental-scale change researches into the Southeast Asian sub-region, the IIS has provided Asian Center for Research on Remote Sensing, AIT one identical MODIS receiving facility. That station is managed by the Joint Management Committee composing of ACRoRS (AIT), Geo-Informatics and Space Technology Development Agency (Thailand).
In this study, the comparison of the heat island intensity for cities in East Asia, different stages of economic development in different geographic locations.
Data used
In this study, five cities are picked up for analyzing the heat environment so called heat island. The cities are: Tokyo (Japan), Seoul (South Korea), Pyongyang (North Korea), Beijing and Shanghai (China), those are within the coverage of the ground station of Univ. of Tokyo, Komaba, and Tokyo. Table-1 shows the list of data used in this study. In order to obtain cloud free data, the date for summer data and winter data, and the time for day-time data and night-time data are not unified. For example, the date of summer-night data for Tokyo is 2nd of June, which is rather early comparing the date for summer-day data, which is observed on 24th of July. In this study, the differences are modified by normalized methodology.
Table-1 List of Data used
| City |
Summer/Winter |
Day/Night |
Date |
Local Time |
G M T |
| Tokyo |
Summer |
Day |
2001/07/24 |
10:36 |
01:36 |
| Night |
2001/06/02 |
22:04 |
13:04 |
| Winter |
Day |
2001/11/23 |
11:08 |
02:08 |
| Night |
2001/11/23 |
22:11 |
13:11 |
| Seoul |
Summer |
Day |
2001/08/27 |
11:59 |
02:59 |
| Night |
2001/08/27 |
23:03 |
14:03 |
| Winter |
Day |
2001/11/19 |
11:32 |
02:32 |
| Night |
2001/11/19 |
22:35 |
13:35 |
| Pyongyang |
Summer |
Day |
2001/08/27 |
11:59 |
02:59 |
| Night |
2001/08/22 |
22:45 |
13:45 |
| Winter |
Day |
2001/11/19 |
11:32 |
02:32 |
| Night |
2001/11/19 |
22:35 |
13:35 |
| Peking |
Summer |
Day |
2001/08/21 |
11:33 |
03:33 |
| Night |
2001/08/20 |
21:57 |
13:57 |
| Winter |
Day |
2001/11/20 |
11:13 |
03:13 |
| Night |
2001/11/20 |
22:17 |
14:17 |
| Shanghai |
Summer |
Day |
2001/07/21 |
10:42 |
02:42 |
| Night |
2001/0917 |
22:19 |
14:19 |
| Winter |
Day |
2001/10/30 |
10:56 |
02:56 |
| Night |
2001/10/30 |
22:00 |
14:00 |
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