Kensuke Goto

A map is the major tool in measuring fractal dimension of a river line whereas in this paper satellite remote sensing data were used in conjunction with the box-counting method. Satellite numeral data ware of LANDSAT/MSS, LANDSAT/TM and SPOT/HRV.Some rivers in the northern part of Kyushu district, Japan were treated with, fractal dimensions of which were measured by using not only each satellite numeral data but a combination of two or three kinds of satellite numeral data.Furthermore a change of Shoka river in China for floods were measured by fractal theory. The following conclusions were obtained: (1)Fractal dimensions of objected rivers had values close to 1.0 showing that the river lines were not so complex. (2)There was little difference in fractal dimension between by use of each satellite numeral data and a combination of two or three kinds of satellite numeral data. (3)Satellite numeral data were clarified to be very useful in measurement of fractal dimension of river lines. (4)A spread of a river width by floods were neasured by fractal dimension using satellite numeral data.

The aim of this study is to determine the optimum vegetation index for analysing damage due to a forest fire and to obtain a damage-degree map of the forest fire based on the optimum vegetation index, by using satellite remote sensing. The forest fire which occurred at Kuji City, Iwate Prefecture on April 27,1983 was treated, Landsat/MSS data before and after the forest fire were used, and six vegetation indices namely RVI, DVI1,DVI2,NDVI, TVI and GVI were compared in order to decide the optimum vegetation index. The F-test together with the t-test was carried out for the ratio of the individual vegetation index before and after the forest fire resulting in it that DVI2 was the optimum. Lastly the damage-degree map of the forest fire was obtained by the optimum DVI2 vegetation index, being very appropriate in comparison with in-situ survey and the air photo analysis.

The Typhoon 9119 attacked the northern part of Kyusyu District, the western part of Yamaguchi Prefecture and Hokkaido District on September 27 to 28,1991. This typhoon was so strong that considerable damages on cedars forests in Hita City, Oita Prefecture, apples orchards in Aomori Prefecture and others were yielded. One of its characteristics was a windy typhoon which triggered a lot of power failures due to salt damage in Chugoku District including Hiroshima, Yamaguchi and Okayama Prefectures. In this paper the authors analysed these power failures in Yamaguchi Prefecture by comparing two sets of the vegetation vigour data obtained from satellite remote sensing before and after the typhoon. The satellite data were MOS-1/MESSR data with the space resolution of 50 m and the vegetation vigour was calculated by RVI (Ratioed Vegetation Index). As a result the distribution map of salt damages examined by RVI almost coincided with that of salt-damage triggered power failures obtained by surveying in situ. Lastly the countermeasure against this kind of power failures was proposed with space and ground remote sensing technique.

As a result of the windy with little rain Typhoon 9713 which passed around the vicinity of Nansei Islands, Japan on August 18,1997,a lot of salt damages occurred on the sugar cane fields. In order to evaluate these damages the ground remote sensing technique together with the Landsat Satellite data were used. At first as of the in-situ investigation by using the ground remote sensing technique such as a portable photometer and a thermal infrared camera at Amami-Oshima Island it was cleared that the damages occurred on the sugar cane farms by the salt water can be easily observed. Secondly, through the analysis of the Landsat Stellite data it was found out that the damaged areas in Amami-Osima and Kikaishima islands can be detected by evaluating the normalized difference vegetation index (NDVI). Finally, based on these investigations the authors proposed that early detection with the ground remote sensing, the exact grasp of damaged areas using the satellite data and sprinkling with water sprinklers or vaccum cars are effective as the countermeasure against salt damages of suger cane fields.