| Project/Area Number |
18510019
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | National Institute of Advanced Industrial Science and Technology |
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Principal Investigator |
MURAYAMA Shohei National Institute of Advanced Industrial Science and Technology, AIST, Research Institute for Environmentak Manegement Technology, Senior Researcher (30222433)
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| Co-Investigator(Kenkyū-buntansha) |
KONDO Hiroaki Research Institute for Environmentak Manegement Technology, Group Leader (60357051)
SAIGUSA Nobuko Research Institute for Environmental Management Technology, Senior Researcher (00251017)
MORIMOTO Shinji National Institute of Polar Research, Division for Research and Education, Assistant Professor (30270424)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥4,020,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥420,000)
Fiscal Year 2007: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2006: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | stable oxygen isotopic ratio / carbon cycle / exchange between atmosphere and forest ecosystem / hydrological processes / isotopic discrimination / 大気-森林生態系交換 |
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| Research Abstract |
Systematic measurements of atmospheric CO_2 concentration and its stable oxygen isotopic ratio (δ^<18>O) in and above the forest together with δ^<18>O of CO_2 in soil an, precipitation, soil water, water vapor and leaf water were made in a cool-temperate deciduous forest at Takayama site in central Japan. Using the observed data, temporal variations of δ^<18>O discriminations during photosynthesis and ecosystem respiration were estimated, and possibility of separating these carbon budget components from net ecosystem CO_2 exchange obtained from the eddy covariance flux measurement was examined. δ^<18>O of atmospheric CO_2 showed more complicated diurnal variation than CO_2 concentration, but prominent δ^<18>O increase appeared in the daytime under sunny and dry conditions, reflecting increase of photosynthetic ^<18>O discrimination. Seasonal variation of daytime δ^<18>O of CO_2 above the forest showed scattered but low values in winter and high values in spring. From late spring to early fall, significant year-to-year difference of the variation was seen with low and high values under respective rainy and sunny summer conditions, which may reflect difference of biological and hydrological processes due to that of meteorological conditions associated with the Asian summer monsoon. Comparison with the data at northern mid latitude sites suggested that the rapid decrease of δ^<18>O seen at Takayama in early summer of the rainy summer year is characteristic of the monsoon Asian region. From comparison of the CO^<18>O fluxes associated with photosynthesis and respiration calculated using a simple one-box canopy air model with the variation of the observed δ^<18>O of CO_2, it was found that the model cannot adequately simulate the δ^<18>O variation. The result suggested that analyses of the δ^<18>O data using a multi-layered canopy process model are necessary to precisely separate photosynthetic and respiratory CO_2 fluxes.
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