| Co-Investigator(Kenkyū-buntansha) |
HIRAHARA Yasuhiro Graduate School of Science, Nagoya University, Associate professor, 大学院・理学研究科, 助教授 (30252224)
YAMAGUCHI Yasushi Graduate School of Science, Nagoya University, Associate professor, 大学院・理学研究科, 助教授 (80283472)
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| Research Abstract |
For the purpose of understanding a coupled cycle of material and energy flows in the earth system, a global scale numerical model was constructed by considering interactions and feedbacks among four spheres (atmosphere, biosphere, lithosphere, and hydrosphere). As a result of simulation by this model, we found that the global terrestrial net primary production (NPP) had been increasing since 1920s, and the NPP increase was approximately 1.3% over 10 years in 1980s. On the other hand, time sequential remote sensing data sets obtained by earth observation satellites were used to give constraints to the numerical model.
As a result, the increase in the global NPP by the terrestrial vegetation was estimated at 2 to 4 % over 10 years in 1980s. We found significant increases in the areal and temporal NPP variations, e.g. in the northern middle-high latitude areas, where annual and seasonal NDVIs and temperature were positively correlated. The temporal vegetation variations were verified locally in the test sites such as the suburbs of Nagoya City, Aichi Prefecture, using the Landsat MSS and TM data. These high spatial resolution data obtained by earth observation satellites were also used to analyze important parameters in the material and energy cycle model, e.g. evapotranspiration and reflectance
The observation performances of ASTER, which is the latest high resolution multispectral imager, were confirmed to meet the baseline requirements. The ASTER data were successfully used to estimate deforested areas in Brazilian Amazon. Spectral properties of various materials were measured in our laboratory as fundamental data for interpretation of remote sensing data.
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