- 著者
- Hiroshi Takagi Akihiko Ito Heon-Sook Kim Shamil Maksyutov Makoto Saito Tsuneo Matsunaga
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.17, pp.213-219, 2021 (Released:2021-12-14)
- 参考文献数
- 45
- 被引用文献数
- 2
Numerous wetlands, including the world's two largest contiguous wetlands, lie along the free-flowing Paraná and Paraguay Rivers that travel the length of subtropical South America (SSA) region. These wetlands are floodplains that are inundated with rising river water in flood events; their morphology and area are highly changeable with flooding extent. The long-term variability of methane emission from this wetland hotspot and its sensitivity to meteorological conditions are not well known. We herein explore this unknown using space-based estimates of methane flux for the SSA region between 2009 and 2015 along with data of water balance. We find that methane emission from this region coherently varies with precipitation and inundation areal extent.
- 著者
- Hiroshi Takagi Akihiko Ito Heon-Sook Kim Shamil Maksyutov Makoto Saito Tsuneo Matsunaga
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- pp.2021-037, (Released:2021-10-13)
- 被引用文献数
- 2
Numerous wetlands, including the world's two largest contiguous wetlands, lie along the free-flowing Paraná and Paraguay Rivers that travel the length of subtropical South America (SSA) region. These wetlands are floodplains that are inundated with rising river water in flood events; their morphology and area are highly changeable with flooding extent. The long-term variability of methane emission from this wetland hotspot and its sensitivity to meteorological conditions are not well known. We herein explore this unknown using space-based estimates of methane flux for SSA region between 2009 and 2015 along with data of water balance. We find that methane emission from this region coherently varies with precipitation and inundation areal extent.
- 著者
- Akihiko ITO Kazuhito ICHII
- 出版者
- The Society of Agricultural Meteorology of Japan
- 雑誌
- 農業気象 (ISSN:00218588)
- 巻号頁・発行日
- pp.D-20-00024, (Released:2020-12-25)
- 参考文献数
- 178
- 被引用文献数
- 3
A wide variety of models have been developed and used in studies of land-atmosphere interactions and the carbon cycle, with aims of data integration, sensitivity analysis, interpolation, and extrapolation. This review summarizes the achievements of model studies conducted in Asia, a focal region in the changing Earth system, especially collaborative works with the regional flux measurement network, AsiaFlux. Process-based biogeochemical models have been developed to simulate the carbon cycle, and their accuracy has been verified by comparing with carbon dioxide flux data. The development and use of data-driven (statistical and machine learning) models has further enhanced the utilization of field survey and satellite remote sensing data. Model intercomparison studies were also conducted by using the AsiaFlux dataset for uncertainty analyses and benchmarking. Other types of models, such as cropland models and trace gas emission models, are also briefly reviewed here. Finally, we discuss the present status and remaining issues in data-model integration, regional synthesis, and future projection with the models.
- 著者
- Akihiko ITO
- 出版者
- The Society of Agricultural Meteorology of Japan
- 雑誌
- 農業気象 (ISSN:00218588)
- 巻号頁・発行日
- vol.77, no.4, pp.211-223, 2021 (Released:2021-10-10)
- 参考文献数
- 104
The increasing amount of measurement data on land-atmosphere flux has made it possible to assess the interannual and longer processes that are driven by environmental change and disturbance of terrestrial ecosystems. In this study, I used a global dataset of carbon dioxide (CO2) fluxes at eddy-covariance tower sites (FLUXNET2015) to investigate long-term trends of net ecosystem CO2 exchange (NEE), gross primary production (GPP), ecosystem respiration (RE), and related variables. From 118 sites with records of at least 5-years duration, I extracted 1198 site-years of data for use in my analyses. Applying moderate screening by data quality, I found that 58% of the sites showed increasing trends as net CO2 sinks, in which median slopes of annual NEE of -1.4 and -4.1 g C m-2 y-2 were obtained by linear regression and Sen’s slope estimator. Both GPP and RE showed increasing trends at different slopes; their slopes were positively correlated among sites. Across-site variation of NEE trends was analyzed by generalized linear mixed modeling; the best statistical model used temperature, stand age, and biome type as explanatory variables. The trend of increasing CO2 sinks differed among biome types, from almost none in grassland and savanna to steep slopes in deciduous broad-leaved forest sites. The flux trends derived from terrestrial model simulations showed that the increasing sink trend also prevails over the land. The global model simulations implied that the increasing land sink is primarily attributable to elevated CO2 concentration. These results demonstrate the usefulness of flux measurement datasets, especially in conjunction with models, to deepen our understanding of long-term terrestrial ecosystem processes.
- 著者
- Akihiko ITO Shimpei INOUE Motoko INATOMI
- 出版者
- The Society of Agricultural Meteorology of Japan
- 雑誌
- 農業気象 (ISSN:00218588)
- 巻号頁・発行日
- vol.78, no.2, pp.56-65, 2022 (Released:2022-04-10)
- 参考文献数
- 62
- 被引用文献数
- 8
Evaluating regional budgets of methane (CH4), a potent greenhouse gas and short-lived climate forcer, is an important task for future climate management. This study estimated historical CH4 emissions from paddy fields in East Asia by using a process-based terrestrial biogeochemical model driven by climate and land-use data. To capture the range of estimation uncertainty, this study used two CH4 emission schemes, four paddy field maps, and two seasonal inundation methods for a total of 16 simulations. The mean CH4 emission rate during 2000-2015 was estimated to be 5.7 Tg CH4 yr-1, which is similar to statistical inventories and other estimates. However, the large standard deviation (± 3.2 Tg CH4 yr-1) among the simulations implies that serious estimation uncertainties remain. Three factors - CH4 emission scheme, paddy field map, and inundation seasonality - were responsible for the disparity of the estimates. Because of the lack of historical management data, the model simulation did not show a decreasing trend in the agricultural CH4 emissions. A sensitivity analysis for temperature indicated that a 1-2 °C temperature rise (typical warming in mitigation-oriented scenarios) would substantially enhance CH4 emissions. However, a sensitivity analysis for water management indicated that a lower water-table depth would largely mitigate the emission increase. Additional studies to improve agricultural datasets and models for better paddy field management are still needed.
- 著者
- Akihiko ITO Kazuhito ICHII
- 出版者
- The Society of Agricultural Meteorology of Japan
- 雑誌
- 農業気象 (ISSN:00218588)
- 巻号頁・発行日
- vol.77, no.1, pp.81-95, 2021 (Released:2021-01-10)
- 参考文献数
- 178
- 被引用文献数
- 1 3
A wide variety of models have been developed and used in studies of land-atmosphere interactions and the carbon cycle, with aims of data integration, sensitivity analysis, interpolation, and extrapolation. This review summarizes the achievements of model studies conducted in Asia, a focal region in the changing Earth system, especially collaborative works with the regional flux measurement network, AsiaFlux. Process-based biogeochemical models have been developed to simulate the carbon cycle, and their accuracy has been verified by comparing with carbon dioxide flux data. The development and use of data-driven (statistical and machine learning) models has further enhanced the utilization of field survey and satellite remote sensing data. Model intercomparison studies were also conducted by using the AsiaFlux dataset for uncertainty analyses and benchmarking. Other types of models, such as cropland models and trace gas emission models, are also briefly reviewed here. Finally, we discuss the present status and remaining issues in data-model integration, regional synthesis, and future projection with the models.
- 著者
- Masanori Iwata Toyozo Takahashi Yuri Takahashi Akihiko Ito Yoshiharu Machida
- 出版者
- Japanese Society of Pharmaceutical Health Care and Sciences
- 雑誌
- 医療薬学 (ISSN:1346342X)
- 巻号頁・発行日
- vol.27, no.1, pp.63-68, 2001-02-10 (Released:2011-03-04)
- 参考文献数
- 16
- 被引用文献数
- 3 4
The therapy of mass alimentary intoxication caused by Salmonella and Enteropathogenic Escherichia coli is discussed. Endotoxin causes fervescence, disseminated intravascular coagulation or shock. When antibiotics are administered for the treatment of alimentary intoxication, toxicity of the endotoxin from the defluvium of bacillus mort body can cause serious symptoms.We noted the strong adsorption force of medicinal carbon and evaluated the endotoxin adsorption ability of medicinal carbon quantitatively using a chromogenic endotoxin specific assay quantitatively. Methods for evaluating damage due to the oral invasion of endotoxin have hardly been developed. The presence of alimentary intoxication due to a large quantity of endotoxin in intestine was assumed, and an in vivo test was performed to evaluate the endotoxin adsorption ability of medicinal carbon based on the influence of particle size. An in vitro test showed the adsorption coefficient to increase with the reaction times of medicinal carbon and endotoxin. The quantity of adsorption of endotoxin decreased as the particle size of medicinal carbon increased. As in vivo test showed that a change in the body temperature of mouse, which is an index of the physiological activity of endotoxin, was reduced by the oral administration of medicinal carbon. Consisting of small sized particles is thus considered to have a useful synergistic effect on the antibiotic treatment of food poisoning.