Fluid dynamic characteristis of jet, which is one of interesting topics in turbulent flow research, have been studied by many reseachers. Although recent some trials to apply coherent vortex structure theory on the study of turbulent jet are considered being interest to the author, it is considered that almost all exsisting researches are either theoritical or experimental ones. In this paper, the author tries to indicate some derterministic features of the turbulent buoyant jet as well as non-buoyant jet in straits and coastal zones by remote sensing including aero photograph, colour analysis of sound echo and Landsat data analysis. Physical model studies are also introduced to supplement the analyses. With analysis of field observation data of tidal jet in Naruto strait, the anthor shows that dynamic vortices shall be generated along shear layers when the jet strouhal number at the end of potential core is of 0.2 through 0.5. The colour sonar analysis shows definitely vertical profiles of the above coherent vortices. With regarding to the jet characteristics in the far field, Landsat data of several buoyant jets discharged into Japan sea from rivers including Shyo, Kuzuryu, Tedori and Mogamic are discussed.
The synthetic aperture radar (SAR) images produced from the Seasat SAR data have provided useful all-weather topographical information. In order to produce a SAR image, the raw data is compressed by the action of matched filters, first in the range direction, then in the azimuth direction. The estimation error in a coefficient of the azimuth matched filter, called Doppler rate, causes image slip between looks. The image slip gives rise to most degradation of SAR multi-look image in look summation operation. In order to reduce the degradation and produce a high resolution SAR multi-look image, an image slip detection type auto-focusing will be effective on condition that the precisely measured image slip data is given. One of the conventional image slip measurement method is based on the cross-correlation between two looks of one scene. But, it is dependent on the characteristics of the scene. This paper describes an improved method called three looks correlation. In this method, the measurement error is reduced by measuring and selecting the image slip among three looks of various scenes. The results of the Doppler rate auto-focusing tests show that the proposed method can reduce the measurement error by half in comparison with the conventional one.
This paper reviews the method and results of the airborne SAR survey which was conducted by NEDO (New Energy Development Organization) as a part of the Nation-Wide Geothermal Survey Project. The whole Japanese Islands except IzuOgasawara Islands were covered by non-stereo/west-look SAR images. In addition to this, main geothermal area was covered by non-stereo/northlook images and Izu peninsula was covered by stereo/north and west-look images. The SAR holographic date was processed through an optical correlator to present the mosaic image of scale 1 : 200, 000. The geological and geothermal interpretation of the images are now under progress. This paper presents several SAR images as well as maps produced from SAR images. Some technical problems arisen during the data acquisition (flight) are also presented.