The influence of radar look-direction on the detectability of lineaments is investigated using low depression angle SAR images of Japan. Regardless of various trends of general geologic structure in interpreted areas, the results of lineament interpretation show selective enhancement of lineaments with strikes at 20-30 degrees to the look-directions. To explain this tendency, a topographic model is proposed, which is modified from the model of Wise(1969) to fit dissected topographic relief in mature stage of Japan. That is, the author took into account of the influence of radar shadow formed by 1st order valleys develop in smooth slope of the Wise' s model. Based upon this modified model, the geometrical relationship among look-direction, depression angle and the angle of 1st order valley slopes provides the conditions for maximum shadow enhancement, and relative frequency of the valleys which satisfy these conditions becomes maximum when the strikes of the valleys are 20-30 degrees to the look-directions.
To improve an accuracy of satellite cloud height measurements, a stereoscopic technique has been studied. For stereoscopic measurements by using geosynchronous meteorological satellite, a precise image navigation technique and data handling time are strictly required, that have not yet been made in the current operational service, whereas the vidicon camera image data by the ETS-III orbital satellite (Engineering Test Satellite), which has a spacial resolution of about 0.4km, is suitable for stereoscopic measurement of cloud height, because of its higher resolution and lower image distortion than can be expected in geostational meteorological satellites. The results of stereoscopic analysis of the ETS-III vidicon camera data show that the data has a capability of determining the cloud height with the accuracy of about 2.6km by preliminary data process. Therefore the ETS-III vidicon camera has an ability of offering us an useful data for cloud height determination as an operational meteorological satellite service.
A new lidar technique for measuring the profiles of backscatter ratio, atmospheric visibility, and atmospheric temperature is proposed. Based on the theory of high resolution Rayleigh/Mie scattering, the feasibility and advantages of using atomic vapor cells as blocking filters for measuring atmospheric parameters are demonstrated with a numerical example worked out in detail. Ten percent accuracy in determining backscatter ratio and visibility can be achieved easily. With a SNR of 300, temperature of 1 K accuracy can be measured directly along with the backscatter ratio to a better accuracy of±1%. Using a large lidar system and assuming 50-km visibility, the proposed technique can be applied to measure backscatter ratio and temperature profiles simultaneously for a 10-km path with 30-m depth resolution in 3 min. With higher SNR the atmospheric pressure profile can also be determined.
This paper deals with the possibility of quantitative remote sensing of water quality. Particularly, influence of light reflection on water surface in this remote sensing and its removal method are discussed. As a matter of course, reflected light of sky light or sun light on water surface acts as noise only. First, reflectance of water surface is compared with spectral reflectance of turbid and clear water in the 0.4-0.7, μm wavelength range. As a result of comparison, reflectance of water surface is as large as another one. Therefore, it shows that elimination of the reflected light from water surface is indispensable to this remote sensing. Then, to eliminate this light, basic form of MSS sensor used polarization characteristics is investigated, and ability of this sensing method for real sea surface is examined. It is concluded that the influence of the reflection on water surface can be eliminated by conical scanning type sensor equipped with polarized filter, and that effectiveness for real sea surface is confirmed.
Experiments of visual extaction of lineaments based on three types of color composite imageries of Landsat MSS covering a geologically complicated part of Korean Peninsula were made. The first type of the imageries was false color made from the combination of MSS Band-4, -5 and -7 while that of the second type was false color made from a combination of Band-5 and -7 in which Band-5 transparency was used twice, i. e. it was used instead of Band-4 in the regular type of the false color imagery. It was found that the score of extracting geological information obtained from the two types of imageries was almost same leading to a conclusion that the so called 2-band false color imagery is good enough for practical use in geological study. Based on the result of the experiments, a false color mosaic of Korean Peninsula was first made using multitemporal 240 and 70 mm transparencies as the basic data for the geological study of Korean Peninsula. Density adjustment was performed for different generation transparencies taking the second generation negative transparency as a standard. In the process of color composition, Kodak Wratten Filter 98(Blue) and 99(Green) were used for Band-5 and Kodak Wratten 25(Red) was used for Band-7 transparencies respectively. It is found that the false color mosaic thus made is useful to obtain geological features especially those of lineament.
It has been recognized that better accuracy is obtained by not only to analize two-dimentionally represented image from LANDSAT MSS data but also to considering with geographical informations. Elevation data to be combined with LANDSAT MSS image must be the mesh data of the area on the earth surface corresponding to the size of a pixel in LANDSAT MSS data. Presently availavle national land digital information prepared by National Land Agency is 250m mesh and it is too large to represent LANDSAT MSS image in three dimention. Terefore, Remote Sensing Center of Nihon University to which the author belong has developed about 75m mesh national land digital data ; that is the whole areas of Tokyo Metropolis, Kanagawa Prefecture, Yamanashi Prefecture, Saitama Prefecture, Ibaraki Prefecture and Chiba Prefecture and a portion of Shizuoka Prefecture. As the example which pixel grid size elevation data sized LANDSAT MSS data is usefull for geographical information, the author takes this opportunity to describe the preparation procedure of our avove-mentioned data and illustrate some example ; the first one is perspective image of the whole area of Chiba Prefecture showing the location of steep slope in danger of landside pointed out by the prefectural authorities. The second one is image of directions of mountainside slope in Hayakawa watershed of Fujigawa water system in Yamanashi Prefecture. The third one is the image of Izu Peninsula including Mt. Fuji is the highest in Japan, derived from its LANDSAT MSS image combined which elevation data and etc.. The author suggests that the analysis of combined LANDSAT MSS data and pixel grid size elevation data of LANDSAT MSS is available for the field of investigation of water accidents, investigation of earth resourses and geographical analysis.