This study is aimed at improving the accuracy of forest type classification and estimating of the states of forest floor using multi-temporal satellite data as part of evaluating hydrological characteristics of the ground surface and subsurface for regional groundwater flow simulation. The study area is 5km×5km located in the Tono region, Gifu, central Japan. The forest in the study area is composed of three forest types; evergreen coniferous forest, deciduous broad-leaved forest and mixed forest consist of them. The author has attempted a forest type classification based on seasonal variation of NDVI calculated using multi-temporal SPOT data observed in summer, autumn and winter. The results of analysis realize that the distributions of residual NDVI between summer and autumn of coniferous forest and broad-leaved forest have good selectivity, the degree in separation of residual NDVI distributions between summer and winter is less than that between summer and autumn due to influence of forest floor evergreen plants, and the residual NDVI distribution between summer and winter is useful for classification between forest and grass field. This analysis also shows that information of phonological NDVI variation regime of each forest type could be useful for estimating forest structure.
In the present research, the authors examined the effects of the probability distribution of the target shape to the results of four component decomposition. The four component decomposition method decomposes polarimetric microwave data into four components, i.e. surface scattering, double bounce scattering, volume scattering and helix scattering. Prior to the present research, three dimensional structure of the rice was measured and modeled. The model was used to calculate the probability density funtion of the rice leaves at a viewpoint of arbitrary zenith and azimuth angles. With this probability density function, a covariance matrix of volume scattering for the rice was developed. This covariance matrix was embedded in the four component decomposition, and it was applied for the polarimetric X-band scattering data of rice, measured in an anechoic radio wave chamber in Niigata Univ. during September 25 to 26, 2007. It was found that the proposed four component decomposition produced more volume scattering and less surface scattering than the results produced by the standard four component analysis. As a result, it is concluded that the probability distribution of the target shape should be considered.
In Japan, There are some nature parks in the mountain area around the country. These parks are valuable as walking and hiking place for many people who are not only keeping health but also enjoying the own view and landscape. In order to experience such situation easily, landscape simulation on a PC is convenient tool. Therefore, 3D data acquisition for the spatial of nature park are needed for achievement of the landscape simulation. However, there are some issues for 3D measurement for the spatial of nature, e.g. without GCPs, difficult to acquisition of stereo images, and so on. In these circumstances, 3D measurement method by using walking direction images is developed. Accuracy evaluation for the method and 3D modeling for a part of Oze national park are investigated in this paper.
The presence of clouds affects the radiance observed by optical sensors at the top of the atmosphere, and thus prevents accurate estimation of physical parameters on the land surface through optical satellite data. In order to overcome this problem, composite methods (MVC, MVI, etc.) were developed to reduce the effect of clouds. However, it is still uncertain whether the use of composite data completely eliminates the cloud interference. Therefore, in this research, the White object Index (WI) is proposed to estimate the cloud coverage for each pixel of MODIS data. Here White objects include both clouds and snow, so it is necessary to isolate the snow factor using the Normalized Difference Snow Index (NDSI) . Using satellite data, the spectral characteristics of cloud, vegetation and soil are analyzed and compared. Then, the ratio of cloud cover, the WI, is obtained from these characteristics. The variation between visible band and shortwave infrared band (2.1μm) has a large effect on the calculation of the WI. In order to test the effectiveness of this system, the results obtained from the WI calculations were thus compared with the cloud ratio from a synthetic mixture model composed of known ratios of cloud, vegetation and soil spectrums. The results showed only a 5% maximum error, indicating that in analyzing composite MODIS data, WI is an effective index for determining the amount of remaining cloud cover. In addition, the WI results were compared with a cloud mask image (MODIS product: MOD35), indicating that the WI produced a more detailed cloud distribution than the MOD35.
An earthquake-fault-like structure was reported in the north of the Aratozawa dam after the Iwate-Miyagi Nairiku Earthquake in 2008. Horizontal displacements around the structure were measured by photogrammetry. We found 2 rigid blocks on both side of the structure. Comparing with the nearest GPS-based control station (permanent GPS receiving station), we judged that relative displacement between the rigid blocks was caused by the movement of the earthquake fault. Displacements are smoothly varying between the structure and the rigid blocks. Therefore we concluded that the structure is based on the movement of the earthquake fault.