ESTIMATION OF THE DIFFUSION
COEFFICIENT OF THERMAL POLLUTION
K. TAKEUCHI'
Osrrka District Meteorological Observatory. Osaku, Japan
AND
s. I T 0
Japrrri Muteoroloqical Associofion. Tokyo. Japan
1. INTRODUCTION
The thermal pollution as well as the air pollution caused by large power
plants has recently become a serious problem in Japan. However, since it has
been rather difficult to measure the temperature distribution of a water
surface over a wide area, studies on thermal pollution have not made rapid
progress.
We have recently observed the surface temperature distribution of
thermally polluted water with an infrared radiation thermometer installed
on an airplane. After some processing of the data thus obtained, the distribution of temperature was displayed as a picture of different coloration according to temperature. An analysis was then made of the turbulent diffusion of
thermal pollution.
The case studied here may be considered typical of the diffusion from a
continuous point source and the simplest kind of oceanic pollution. The aim
of the present study is to find clues to the complicated problems of oceanic
diffusion.
2. INSTRUMENT AND OBSERVATION
The use of an infrared radiometer for measuring the surface temperature
of an object is well known. Ochiai (1973) has recently used the radiometer
for observing the temperature and pollution of the sea surface. In the present
study, too, an airborne infrared radiometer was used to observe the temperature of a wide area of sea surface. thus saving manpower and time. The
' Prpsent utldress ; Meteorological Research Institute, Tokyo, Japan.
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