Laser radar (lidar) is an excellent remote monitoring method for obtaining spatial resolved information of the atmosphere. This paper consists of the followings : 1) an outline of the principle in laser radar measurement and types of laser radars, 2) laser radar systems, and 3) measurements of typical phenomena in air pollution and air-pollution related meteorology, using three laser radar systems (a mobile Mie-scattering laser radar, a large laser radar and a differential absorption lidar (DIAL)) at National Institute for Environmental Studies. Described phenomena cover aerosol dispersion of a stack plume, NO₂, concentration distribution in a plume, temporal and spatial structures of atmospheric boundary layer using an aerosol distribution as an indicator, and wide-area pollution map. In addition, data processing of image data of wide-area pollution is described.
by Nobuo Takeuchi

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Remote sensing techniques have provided new scientific tools for measuring water qualities in the natural environment. Interpretation of the signals recieved by remote sensor may make it possible to assess the water qualities both in quantitative and qualitative way. As yet, however, little is known about the specific effects on the spectral reflectance of the water body. Laboratory and field spectro-metric studies, along with theoretical studies of bio-optics, are the means by which these characteristics will be defined.
This paper describes field experimental work which forms part of an overall program intended to identify effects of water quality measurement by remote sensing. The measurements of spectral reflectance just above and below the surface, and water quality measurements were carried out at Lake Kasumigaura. Correlation coefficients were culculated on the spectral reflectance and water qualities.
The results showed that :
(1) Water qualities were highly correlated with the spectral reflectance above the surface at the region of 720nm while the other regions showed insignificant results. However, correlation between spectral reflectance just below the surface and water qualities was significant at 540nm and 694nm regions.
(2) Improved correlation can be clearly obtained if we consider the ratio of reflectances R(λ), R(694)/R(442) and (R(442)-R(694))/(R(442)+(694)).

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In order to make various photographic processes more quantitative, we made the photographic processing system which had the computer simulations and the developments of the programs for various photographic processing, the contact printer controlled by a microcomputer, three kinds of automatic processors for development, etc. Photographical density slicing processes and pseudo color processes were fully analyzed and the very useful improvement for these processes were made. Moreover the photographically processed results were consistent very well with the results of the computer silu-lations and analyses. Good advancement on the photographic processing in accuracy and reproduci-bility was attained.

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Ground illumination varies with an angle of the sun to the ground surface. A varied illumination shound be corrected, therefore, in order to obtain an accurate classification of fallen snow surface at a mountanious district using Landsat MSS data. This requires us to obtain the reflectance from the illumination of the snow surface. First, an equation, of which variables derived from the ratio between the direct sun radiation and the diffuse sky radiation, as well as from the angle of the sun to the ground surface, should be introduced. The reflectance will then be estimated through the illumination of the snow surface, should be introduced. The reflectance will then be estimated through the illumination of the snow surface obtained from Landsat data, after finding the optimum coefficients for the equation. Yagizawa Dam Watershed was chosen for this experiment and the digital terrain model was constructed. An analytical study was conducted by having the Landsat MSS data corresponding with the digital terrain model. In deciding the coefficients for the equation, an interactive method was utilized with a color TV monitor. The ratio between the direct sun radiation and the diffuse sky radiation was gradually altered until the brightness on each side of the ridge on the imagery monitor becomes equal. A classification of the snow surface reflectance derived from the new data corrected using the coefficient showed that the classified patterns correspond with changes of contour lines. In conclusion, a geographical correction is necessary to obtain correct illumination from Landsat original MSS data. For more detailed classification of the snow quality, the relation between the classification pattern of snow surface reflectance and snow surface condition shoud be proved and it remains as a future subject.

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Hydrodynamic characteristics of the "Vortex of Naruto" were investigated based on the remotely sensed data. Small scale vortices caused by the fast tidal currents at the Naruto Strait were surveyed through airplane remote sensing. Large scale vortices were surveyed through multi - level remote sensing using Landsat and airplanes. Under sea information was obtained through fluid mechanical analysis aided by the hydraulic model tests. Small scale vortices were explained to be the coherent vortices in the free boundary layers between the tidal current and the dead water regions, and were revealed to cause the strong vertical water mixing at the strait. Large scale vortices were explained to be generated as the results of the amalgamation process of the small scale coherent vortices in 6 hours, and were revealed to cause the effective tidal exchange through the strait between Harima Sea and Kii Channel. Results obtained made it possible to catch the macroscopic view of the hydrodynamic
characteristics of the "Vortex of Naruto", that had not been done by the conventional field survey using boats.

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