Hajime Nishikawa

Satellite analysis for water flow of Lake Inbanuma

Multispectral satellite data sets and site surveyed data was utilized for water quality assessment. Lake Inbanuma represents a complex situation of major optical constituents and emergent spectral signals for remote sensing analysis. As such it provided a good test of the combined radiometric correction methods developed for optically sensed satellite data. Based upon results of repetitive laboratory experiments we examined this region by several field campaigns synchronized date and time with satellite observations. As results, first, in proportion to increased chlorophyll content reflectance absorption appeared in the portion between 625 and 675 nm whereas near infrared peaked at approximately 720 nm. Second, the spectral ratio of red and near infrared reflectance was diagnostically useful for assessing high chlorophyll-a levels in regional water. Third, the chlorophyll-a based trophic state index, established by Carlson in 1977, was used to calculate the results from the field campaign data. Based upon those factors, two transformed Landsat Thematic Mapper data sets were digitally analyzed. The complicated pattern and direction of eutrophic/ hypertrophic lake water flow resulting from the ‘‘open-and-shut operation’’, was analyzed. Regional variances in trophic state index values were observed. Also, the over all change in the trophic state of Lake Inbanuma indicated a specific efficacy in the ‘‘open-and-shut operation’’. The accumulation of these digitally analyzed data will aid in further understanding the appropriate intervals of operation and will contribute to more accurate regional environmental assessments. 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

Simultaneous observation data of GB-SAR/PiSAR to detect flooding in an urban area

We analyzed simultaneous observation data with ground-based synthetic aperture radar (GB-SAR) and airborne SAR (PiSAR) over a flood test site at which a simple house was constructed in a field. The PiSAR under flood condition was 0.9 to 3.4u2009dB higher than that under nonflood condition. GB-SAR gives high spatial resolution as we could identify a single scattering component and a double bounce component from the house. GB-SAR showed that the difference between the flooding and nonflooding conditions came from the double bounce scattering. We also confirm that the entropy is a sensitive parameter in the eigenvalue decomposition parameters, if the scattering process is dominated by the double bounce scattering. We conclude that and entropy are a good parameter to be used to detect flooding, not only in agricultural and forest regions, but also in urban areas. We also conclude that GB-SAR is a powerful tool to supplement satellite and airborne observation, which has a relatively low spatial resolution.

Landsat analysis for evaluating spatiotemporal changes of regional-scale landscapes

This paper evaluates spatiotemporal changes of regional-scale landscapes using Landsat data, which are able to acquire large amount of data since 1972. The data provides high-quality imagery for many different applications such as land cover mapping and change detection. In this study Landsat TM images on November 1985 and October 1997 were used to evaluate quantitative landscape changes of the Chubu and Kinki regions in Japan. Land classification images were analyzed using simple landscape metrics and sequential analysis method. Consequently, we identified that the urban area grew spatially and aggregated around an existing urban core area. This study demonstrates that remote satellite images provide the desired information such as urban planning and regional planning for a spatiotemporal assessment of various regional-scale landscape changes. Keywords-Landsat; landscapes; landscape metrics; spatiotemporal