Variations and Cycles of Greenhouse Gases on the Earth's Surface

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In order to elucidate variations and cycles of greenhouse gases on the Earth's surface, extensive studies with systematic measurements and development of numerical models were performed. The results obtained from this study are summarized as follows :(l) The concentrations and isotopic ratios of various greenhouse gases such as CO_2, CH_4, N_2O, CO, HCFC, HFC, PFC and SF_6 were systematically measured over Japan, the Pacific Ocean, Siberia, Syowa Station and Spitzbergen Islands, and their temporal and spatial variations as well as causes and governing processes were clarified. Measurements of the isotopomers of atmospheric N_2O succeeded for the first time, and quantitative estimation of the N_2O budget was tried on the basis of the measurement results. Double-deconvolution analysis of the CO_2 concentration and its δ^<13>C was also made to elucidate the recent global budget of anthropogenic CO_2. Furthermore, temporal changes in HCFC, HFC and SF_6 emissions were investigated using a n … More orthernsouthern hemispheric two box-model and their measurement results. (2) A three-dimensional atmospheric transport model was developed and then applied to elucidate their global cycles in terms of the concentration and δ^<13>C.A spatially high-resolution ecosystem model was also developed to examine the role of the terrestrial biosphere in the global carbon cycle, and partial pressure differences of CO_2 between the atmosphere and the ocean were calculated and ocean uptake of CO_2 was estimated using a newly developed three-dimensional ocean carnon cycle model. A multi-box model developed in this study succeeded in reconstructing the history of the atmtospheric N_2O concentration over the last 500 years. (3) For a better understanding of the carbon cycle between the atmosphere and the lithosphere, carbon fluxes due to weathering and the release of carbon from the deep underground were quantitatively estimated by their extensive measurements. Systematic measurements were also carried out in several coral reefs in Okinawa, and it was revealed that the role of coral in the ocean carbon cycle was different depending on coral itself. Less