1989 年 9 巻 2 号 p. 175-187
Mt. Sakurajima is continually active at present affecting greatly the surrounding living environment with its volcanic ashes. The Volcanic eruption plume emitted from the crater disperses into the atmosphere and is greatly influenced by the wind velocity and the wind direction in the upper layer.
It is well known that Landsat MSS 4 and 5 band data are more effective than the other band ones to observe the volcanic eruption plume.
Using the Landsat MSS data, we grasped the actual patterns of volcanic ash dispersion over extensive areas, and analyzed its seasonal characteristics and the fluctuation of dispersion as the occasional cases.
Analyzing graphically the MSS data, we obtained the relation between spectral emissivity and the distance from the crater, and the relation between the width of dispersion and the distance from the crater.
The spectral emissivity decreases exponentially according to the distance from the crater.
The width of dispersion to the distance is not always constant, and differs by the conditions of the upper layer.
We were convinced that the method of remote sensing using Landsat data is effective for grasping the actual patterns of dispersion of volcanic eruption plumes.