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 (676KB)
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8,934,000Yen (FY1998; 2,978,000Yen)
The measurements of the atmospheric CO2 concentration, flux, isotope and meteorological conditions using a tower in a temperate deciduous forest situated at the mountainous area of Japan (Takayama-city) were conducted from Oct.,1993 to Mar.,1999. Our objective of this research was to elucidate the carbon cycle in the temperate forest-ecosystem. Main results obtained in this research are as follows;
(1) The seasonal and inter-annual variations of CO2 exchange between the atmosphere and a temperate deciduous forest and the relation of them to meteorological conditions and forest activity were investigated. Average net-uptake of CO2 is 1.2 tC/ha /year, but it has notable variation due to the differences of insolation ,temperature and forest-activity in each year.
(2) Daily values of the net ecosystem production, NEP and the gross primary production, GPP of the forest were estimated from the CO2 flux measurement, and they were parameterized as a function of the air temperature and the absorbed photosynthetic active radiation. APAR. The observed seasonal change in NEP was well simulated by this experimental equation.
(3) Diurnal variations of carbon and oxygen isotopic ratios in the warm season and seasonal variation of the carbon isotopic ratio were observed. From comparison with the CO2 concentration variation, it was suggested that these variations reflect diurnal and seasonal variations of CO2 exchange between the atmosphere and the biosphere.
(4) The emission inventory of CO2 from anthropogenic origin and uptake-release rate of the ecosystem parameterized as a function of air temperature and the PAR were input to mesoscale chemical-transport model and analyzed the portion of CO2 from anthropogenic origin and uptake-release of CO2 by the biosphere.
Carbon Cycle, Temperate Forest, CO2 Flux, Stable Isotopes, Transport Model