Comparison and combination of OCTS and POLDER, which are sister sensors mounted on the satellite ADEOS, are considered from the viewpoint of aerosol retrieval. First it is shown that the latest inflight calibration coefficients for each sensor provide good cross-calibrations between two sensors. Then aerosol characteristics are extracted using the OCTS level-lb data and POLDER level-ldata. From comparison of the retrieved aerosol optical properties, we found that Angstrom exponent is more strongly affected by the fluctuation of radiance than the optical thickness of aerosols is. Distribution maps showing the Angstrom exponent and the optical thickness of aerosols are compiled from the artificial OCTS data contaminated by random error as well as from OCTS raw data on April 26 in 1997, respectively. From these aerosol maps, it can be seen that : 1) the retrieved optical thickness of aerosols includes the same order of error as the radiance error, 2) the Angstrom exponet suffers a error by ten times larger than the radiance one. We can say that Angstrom exponent can not avoid the influence of observational error in radiance, however we can also say that polarization degree is promising to improve this point.
Distribution of FeO and Ti02contents on the lunar surface was mapped by using Clementine UVVIS data in the following sequence. (1) The data was radiometically calibrated. (2) An image map of a large area was created by mosaicking images in one orbit and then between neighboring orbits. (3) The maturity effect was removed by using VIS reflectance data and ratio of NIR to VIS in order to obtain the FeO content parameter. (4) FeO content was derived by comparing the FeO parameter and FeO content that was actually measured for the returned samples by chemical analysis. This method was also applied to estimate Ti02 content with UV reflectance data and UV/VIS ratio. False color composite images were generated by assigning brightness, in addition to FeO and Ti02 contents, to the three primitive colors. We applied this method to two typical lunar maria; Mare Serenitatis and Mare Moscovience, and investigated lunar surface lithologies and geologic histories of these regions.
At present, NOAA/AVHRR 10-day mosaic composite image for the total Asian region is undertaking. This paper is concerned with development of an algorithm to extract optimal data for the purpose. Generally, such algorithm is required to reject cloud data at least, and to pick up less distorted data radiometirically and geometrically. As the first step, by using ground truth data, simulation by 6S code and NOAA/AVHRR image data in Mongolia, effects of atmosphere and bidirectional reflectance were investigated in this Part-1. The apparent reflectance of channels 1 and 2 were highly dependent upon the sun-target-sensor geometry, and the magnitude of disturbances was dependent upon ground covers. Finally, NDVI levels to the maximum NDVI value versus to sensor scan angle in AVHRR scenes for various ground cover conditions were investigated. Further investigation is necessary to establish a more efficient compositing algorithm.
In present paper 3-D remote sensing of woody canopy heights using a new scanning helicopter-borne lidar system with high spatial resolution was examined. This lidar system was characterized by (i) almost ground surface was covered by scanning a laser beam of small-footprints below tens of centimeters, (ii) precise grid data were obtained by rectangular scan using a garbomirror scanner, and (iii) there were two operational modes, first pulse mode (FP-mode) for measuring woody canopy and last pulse mode (LP-mode) for measuring ground level, of time interval meter measuring the elapsed time between the laser pulse emission and the return of the reflected pulse. FP-mode DEM (Digital Elevation Model, grid interval=33.3 cm) and LP-mode DEM were calculated from data measured by FP-mode and LP-mode. DSM (Digital Surface Model) was computed with an error of about 15 cm from the LP-mode DEM. Mesh data (DCHM) of woody canopy heights were obtained by subtracting the DSM from the FP-mode DEM. The laser-derived tree heights of 14 coniferous trees and 6 broadleaf trees estimated from the DCHM were in error by less than 47 cm (RMSE=19 cm) in comparison with the ground measured tree height. The median filter (3x3 mask) was effective for removal of spike noise in the DCHM. The result showed the accuracy of tree height estimate was extremely improved by the mentioned method using the scanning lidar system with high spatial resolution.
CRL/NASDA airborne synthetic aperture radar (Polarimetric Interferometric SAR, PI-SAR) has functions to observe in 2 frequencies (X and L-band), high spatial resolution and full polarimetry. This paper aims to analyze the characteristics of PI-SAR data applied for forest observation. We tried some filtering methods for speckle noise reduction, and recognized that the Frost Filter (3x3) is the most adequate. We compared distinctive abilities between PI-SAR false color composite images (Red, Green, Blue : HH, HV, VV respectively) and TM/CASI/aerial photograph images. It was verified that L-band image showed the feature of tree species as the tone of color, and X-band showed surface texture of forest crown. An inspection of relationship between forest parameters and PI-SAR backscatter coefficient was conducted. In order to avoid the incident angle effect, 1. flight path was set parallel along with straight forestry road about 8 km long. 2. research plots for forest measurement were placed near that forestry road. Distinctive features were expected in the relationship between PI-SAR observation parameters and forest parameters. We measured forest parameters such as leaf area index (LAI), basal area, diameter at breast height (DBH) and top height during a few days just after observation of PI-SAR, and analyzed the relationship in evergreen artificial forest. We also considered about appropriate sampling extent on PI-SAR data for the representative value of the dB for comparison. As the result, we found that L-HV, VH, VV data have significant correlation with forest parameters. L-HH suggested the possibility to distinguish the three categories of tree species (1. evergreen coniferous trees 2. Larix 3. broad leaf trees). We estimated trunk biomass from basal area and standard tree of the stand. And considering about saturation of L-band for forest biomass, we realized that measured plots have smaller volume than saturation revel at L-VV, but bigger at L-HH. The relationship of L-VV and trunk biomass of plots was discribed as σ∝ ∝(trunk biomass)0.28.
In order to research the actual conditions of the urban climate in a provincial city, weather maps were made by drawing with remote sensing data and measurement data of weather. The authors obtained the following results: (1) Land use maps were made by drawing with remote sensing data in Nagano City and Matsumoto City. Data of temperature and relative humidity were collected each land use. (2) Weather maps were made by drawing at an optional season, time and weather condition. For example, they were constructed at the coldest day and the hottest day. (3) A similarity in character of temperature in the commercial district in Nagano City and Matsumoto City was confirmed.