Effects of difference in measurement conditions of airborne scanning lidar systems on the accuracy of the tree heights estimation were investigated to improve the measurement efficiency. At the condition on the flight altitude of 300 m, footprint diameter was small (0.3 m) with low flight speed (60 km/h) and footprint interval of laser beams was set to almost same as the footprint diameter in order to thoroughly scan target canopies. For more efficient measurement, flight speed was raised up to 90 km/h at 500 m altitude condition. In the case, the footprint diameter was also expanded up to 0.5 m, so that footprint interval was almost same as the diameter, as was in 300 m altitude condition. At the condition on 900 m altitude, flight speed was much more raised to 230 km/h, so that the footprint interval became larger than the diameter. After the measurements, tree heights were estimated from the digital canopy height models produced from lidar data obtained at each of the conditions. The root mean square errors of the 166 tree heights estimation were 0.27, 0.30 and 2.38 m for the conditions of 300, 500 and 900 m altitude, respectively. These results showed that, when flight speed is raised for more efficient measurement, it is important for sizes of footprint diameter and interval to be set to almost same to obtain accurate results. It was also shown that tree height estimation with less error can be provided up to 0.5 m footprint diameter by adopting the almost same sizes of the footprint diameter and interval.

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It is important to adopt waste treatment methods and to understand material flow for the creation of a recycling society. We ran anaerobic fermentation in goat-feces in order to understand treatability. In addition, analyzed the fertilizer component of the digested sludge produced by anaerobic fermentation and considered using sludge for cultivation of plants. Initially, we compared the character of feces in some livestock, then realized that goat-feces were similar to cow-feces in low fertilizer component, high C-N ratio, and total solid rate. In the case of short hydraulic residence time of anaerobic fermentation in goat-feces, thermophilic fermentation was better than mesophilic in terms of gas production. The properties of digested sludge were mildly alkaline, about 60% volatile solids and 2-3% total solids in sully form. The sludge contained a fertilizer component especially high in N and K. The collection rate of elements in supernatant liquid of digested sludge was high in N and K but low in P and Ca due to settling out. The supernatant liquid of degested sludge is more suitable than using the digested sludge for hydroponic culture. Compared to the wet oxidation process liquid, the supernatant liquid of digested sludge has no advantage over the collection rate of K and Ca but exceeds in N.

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This study presents an artificial closed system (Arai's Mars Eco-systems Dome, A'MED), which provides a suitable climate for habitation on Mars. We ran some numerical experiments using a Local Circulation Model in order to determine the most suitable structure of the A'MED for a climate close to our terrestrial atmosphere. We tested several upper boundary conditions, which result in green house effects on the atmosphere in the A'MED. The idea of making a Mars habitable system has been proposed by Taylor (1992) and Averner and MacElroy (1976). The difference between this study and those is the energy source which is assumed to be only solar energy, and quantitative investigation for the diurnal variation of temperature and sunshine by which plants can survive. A canopy fixed at a certain altitude is a black body for infrared radiation, and transparent for visible radiation. A dry atmosphere with the same components is assumed. At first the necessary position of the canopy height is estimated between the heights of 1 km and 14 km. A lower canopy makes a stable state more quickly. Upon achieving stable equilibrium conditions, the ground level temperature increased with height of the canopy. However, the canopy surface temperature was not affected by the height of it very much. Although a space colony at 14 km height with one atmospheric pressure does not seem to be realistic, a higher canopy gives a higher temperature. Finally the model suggested that the A'MED with two or three layers of canopies allows the creation of a warmer and milder climate. This study points a way to produce good closed systems, providing a suitable environment for humans and plants by Martian natural solar energy.

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