Some Features of the Urban Environment of Tokyo by Remote Sensing of Ground Surface Temperature
1974 Volume 25 Issue 3 Pages 147-158
Details
1974 Volume 25 Issue 3 Pages 147-158
Four observations of surface temperature of the urban area of Tokyo were performed making use of several airborne remote sensing methods on bright sunny afternoons during summer.
In the first observation (August 30,1971; NATIONAL ER2001 Infrared Thermometer), it became clear that the surface temperature of a river with a vast amount of water has the lowest temperature, natural or near natural forests have the next lowest temperature, an urban area with many highways is hotter than a suburban area with greenery, and a main street with heavy traffic is the hottest. The second observation (August 4-5,1972; NATIONAL ER2002 Infrared Thermometer) revealed the fact that there are many cases requiring +5+10°C corrections of the airborne records on heated roads and buildings.
The detection of a thermal complex which corresponds to an experiment of thermal convective circulation under the inversion layer in a stratified wind tunnel and the indication of the environmental temperature of roadside trees in the heated urban area are major results of the third observation (August 11,1972; AGA Thermovision 680). Seismological Section, Japan Meteorological Agency, Tokyo
In the fourth observation (August 19,1972; DAEDALUS Scanning Radiometer: Digicolor) two thermal maps were analyzed. The first is that of a residential area and the second of a densely populated urban area comprising several large green zones such as the Imperial Palace Grounds. Lower surface temperatures on the leeward side of large green zones and wide rivers (the Sumida and the Arakawa rivers) were clearly noticed.
These observational results suggest the following: Urban air circulation becomes a very complicated regime by compounded heated and cooled areas of various scales under the developed thermal inversion during the sunny days in summer. Such circulation causes a very complicated flow of polluted air resulting in several densely polluted spots in the suburban area.
