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Lee D.K.,Seoul National University | Park C.,National Institute for Environmental Studies | Tomlin D.,University of Pennsylvania
Landscape and Ecological Engineering | Year: 2013

The amount of carbon stored in soil and vegetation varies according to land use. Land-use changes (LUCs) affect those carbon stocks. Changes in carbon stocks also affect greenhouse gas emissions. Predicting LUCs is therefore necessary to establish quantitative targets for carbon dioxide (CO2) reduction. This study attempts to model LUCs and the associated changes in carbon stocks for South Korea between 2005 and 2030. It examines four LUC scenarios suggested by the Intergovernmental Panel on Climate Change. Each scenario is assessed in terms of its effect on South Korean carbon stocks. Under all four scenarios, afforestation leads to carbon sequestration with an average net uptake of 22.4-31.5 MtC. The scenario yielding the highest sequestration rate increase (from 12.4 to 14.1 MtC/year) results in levels of sequestration equal to 8.3 % of South Korea's 2005 CO2 emissions. This is equivalent to a value of 304 million dollars in the European Union carbon market. Clear differences among the scenarios tested suggest that land use must be regarded as an important factor in any plan for future carbon sequestration. © 2013 International Consortium of Landscape and Ecological Engineering and Springer Japan.

Shiogama H.,Japan National Institute of Environmental Studies | Emori S.,National Institute for Environmental Studies | Emori S.,University of Tokyo | Takahashi K.,Japan National Institute of Environmental Studies | And 5 more authors.
Journal of Climate | Year: 2010

The precipitation sensitivity per 1 K of global warming in twenty-first-century climate projections is smaller in an emission scenario with larger greenhouse gas concentrations and aerosol emissions, according to the Model for Interdisciplinary Research on Climate 3.2 (MIROC3.2) coupled atmosphere-ocean general circulation model. The authors examined the reasons for the precipitation sensitivity to emission scenarios by performing separated individual forcing runs under high and low emission scenarios. It was found that the dependency on emission scenario is mainly caused by differences in black and organic carbon aerosol forcing (the sum of which is cooling forcing) between the emission scenarios and that the precipitation is more sensitive to carbon aerosols than well-mixed greenhouse gases. They also investigated the reason for the larger precipitation sensitivity (larger magnitude of precipitation decrease per 1 K cooling of temperature) in the carbon aerosol runs. Surface dimming due to the direct and indirect effects of carbon aerosols effectively decreases evaporation and precipitation, which enhances the precipitation sensitivity in the carbon aerosol runs. In terms of the atmospheric moisture cycle, although changes of vertical circulation offset the effects of changes in the atmospheric moisture in both the carbon aerosol and greenhouse gas runs, the amplitude of vertical circulation change per 1 K temperature change is less in the carbon aerosol runs. Furthermore, the second indirect effect of organic carbon aerosol counteracts the influence of the vertical circulation change. These factors lead to suppression of changes in the moisture's atmospheric residence time and increase of the precipitation sensitivity in the carbon aerosol runs. © 2010 American Meteorological Society.

Aramaki T.,National Institute for Environmental Studies | Nagao S.,Kanazawa University | Nakamura Y.-H.,Hokkaido University | Uchida M.,Japan National Institute of Environmental Studies | Shibata Y.,Japan National Institute of Environmental Studies
Radiocarbon | Year: 2010

During a rainfall event in early September 2006, the transport behavior of particulate organic carbon (POC) in a small river (Teshio River, northern Japan) with alluvial plain and forest characteristics was investigated chiefly with carbon isotopes. The radiocarbon (δ14C value) of POC varied widely from 56‰ at the beginning of the rain event to 10‰ at peak rainfall. The δ14C values have a positive correlation with C/N ratios and a negative correlation with δ13C values except for the data from when both turbidity and water level were at their maximums due to rainfall. These results indicate that the sources of organic matter in the river come from the surface layer of soil as the water level rises during a rainfall event. © 2010 by the Arizona Board of Regents on behalf of the University of Arizona.

Sakurai T.,National Institute for Environmental Studies | Kobayashi J.,National Institute for Environmental Studies | Kobayashi J.,Prefectural University of Kumamoto | Kinoshita K.,National Institute for Environmental Studies | And 13 more authors.
Environmental Toxicology and Chemistry | Year: 2013

The authors investigated the kinetics of transfer of perfluorooctane sulfonate (PFOS) from water, suspended sediment, and bottom sediment to a marine benthic fish, the marbled flounder (Pseudopleuronectes yokohamae). Fish were exposed in 3 treatments to PFOS in combinations of these exposure media for 28 d and then depurated for 84 d. A major part (37-66%) of PFOS in the fish was in the carcass (i.e., whole body minus muscle and internal organs). Three first-order-kinetic models that differed in exposure media, that is, 1) sum of dissolved and particulate phases and sediment; 2) dissolved phase, particulate phase, and sediment; and 3) dissolved phase only, were fitted to the data assuming common rate constants among the treatments. The uptake efficiency of dissolved PFOS at the respiratory surfaces was estimated to be 3.2% that of oxygen, and the half-life of PFOS in the whole body to be 29 d to 31 d. The better fit of models 1 and 2 and the values of the estimated uptake rate constants suggested that the PFOS in suspended and bottom sediments, in addition to that dissolved in water, contributed to the observed body burden of the fish. Based on an evaluation of several possible contributing factors to the uptake of PFOS from suspended and bottom sediments, the authors propose that further investigation is necessary regarding the mechanisms responsible for the uptake. Environ Toxicol Chem 2013;32:2009-2017. © 2013 SETAC.

PubMed | National Institute for Environmental Studies
Type: Journal Article | Journal: Journal of nutritional science and vitaminology | Year: 2013

Although the importance of solar radiation for vitamin D3 synthesis in the human body is well known, the solar exposure time required to prevent vitamin D deficiency has not been determined in Japan. This study attempted to identify the time of solar exposure required for vitamin D3 synthesis in the body by season, time of day, and geographic location (Sapporo, Tsukuba, and Naha) using both numerical simulations and observations. According to the numerical simulation for Tsukuba at noon in July under a cloudless sky, 3.5 min of solar exposure are required to produce 5.5 g vitamin D3 per 600 cm2 skin corresponding to the area of a face and the back of a pair of hands without ingestion from foods. In contrast, it took 76.4 min to produce the same quantity of vitamin D3 at Sapporo in December, at noon under a cloudless sky. The necessary exposure time varied considerably with the time of the day. For Tsukuba at noon in December, 22.4 min were required, but 106.0 min were required at 09:00 and 271.3 min were required at 15:00 for the same meteorological conditions. Naha receives high levels of ultraviolet radiation allowing vitamin D3 synthesis almost throughout the year.

PubMed | Japan National Institute of Advanced Industrial Science and Technology, Japan National Institute of Environmental Studies, National Institute for Environmental Studies and Prefectural University of Kumamoto
Type: | Journal: The Science of the total environment | Year: 2015

We estimated inflow rates of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) to Tokyo Bay, Japan, between February 2004 and February 2011 by a receptor-oriented approach based on quarterly samplings of the bay water. Temporal trends in these inflow rates are an important basis for evaluating changes in PFOS and PFOA emissions in the Tokyo Bay catchment basin. A mixing model estimated the average concentrations of these compounds in the freshwater inflow to the bay, which were then multiplied by estimated freshwater inflow rates to obtain the inflow rates of these compounds. The receptor-oriented approach enabled us to comprehensively cover inflow to the bay, including inflow via direct discharge to the bay. On a logarithmic basis, the rate of inflow for PFOS decreased gradually, particularly after 2006, whereas that for PFOA exhibited a marked stepwise decrease from 2006 to 2007. The rate of inflow for PFOS decreased from 730kg/y during 2004-2006 to 160kg/y in 2010, whereas that for PFOA decreased from 2000kg/y during 2004-2006 to 290kg/y in 2010. These reductions probably reflected reductions in the use and emission of these compounds and their precursors in the Tokyo Bay catchment basin. Our estimated per-person inflow rates (i.e., inflow rates divided by the estimated population in the basin) for PFOS were generally comparable to previously reported per-person waterborne emission rates in Japan and other countries, whereas those for PFOA were generally higher than previously reported per-person waterborne emission rates. A comparison with previous estimates of household emission rates of these compounds suggested that our inflow estimates included a considerable contribution from point industrial sources.

PubMed | National Institute for Environmental Studies
Type: Journal Article | Journal: Journal of epidemiology | Year: 2014

Ambient temperature affects mortality in susceptible populations, but regional differences in this association remain unclear in Japan. We conducted a time-series study to examine the variation in the effects of ambient temperature on daily mortality across Japan.A total of 731 558 all-age non-accidental deaths in 6 cities during 2002-2007 were analyzed. The association between daily mortality and ambient temperature was examined using distributed lag nonlinear models with Poisson distribution. City-specific estimates were combined using random-effects meta-analysis. Bivariate random-effects meta-regressions were used to examine the moderating effect of city characteristics.The effect of heat generally persisted for 1 to 2 days. In warmer communities, the effect of cold weather lasted for approximately 1 week. The combined increases in mortality risk due to heat (99th vs 90th percentile of city-specific temperature) and cold (first vs 10th percentile) were 2.21% (95% CI, 1.38%-3.04%) and 3.47% (1.75%-5.21%), respectively. City-specific effects based on absolute temperature changes were more heterogeneous than estimates based on relative changes, which suggests some degree of acclimatization. Northern populations with a cool climate appeared acclimatized to low temperature but were still vulnerable to extreme cold weather. Population density, average income, cost of property rental, and number of nurses appeared to influence variation in heat effect across cities.We noted clear regional variation in temperature-related increases in mortality risk, which should be considered when planning preventive measures.

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