Watanabe K.,Japan National Institute of Environmental Studies |
Komatsu N.,Ibaraki Kasumigaura Environmental Science Center |
Kitamura T.,Ibaraki Kasumigaura Environmental Science Center |
Ishii Y.,Tokyo Metropolitan Research Institute for Environmental Protection |
And 9 more authors.
Environmental Microbiology | Year: 2012
The free-living, cosmopolitan, freshwater betaproteobacterial bacterioplankton genus Polynucleobacter was detected in different years in 11 lakes of varying types and a river using the size-exclusion assay method (SEAM). Of the 350 strains isolated, 228 (65.1%) were affiliated with the Polynucleobacter subclusters PnecC (30.0%) and PnecD (35.1%). Significant positive correlations between fluorescence in situ hybridization and SEAM data were observed in the relative abundance of PnecC and PnecD bacteria to Polynucleobacter communities (PnecC+PnecD). Isolates were mainly PnecC bacteria in the samples with a high specific UV absorbance at 254nm (SUVA254), and a low total hydrolysable neutral carbohydrate and amino acid (THneutralCH+THAA) content of the dissolved organic matter (DOM) fraction, which is known to be correlated with a high humic content. In contrast, the PnecD bacteria were abundant in samples with high chlorophyll a and/or THneutralCH+THAA concentrations, indicative of primary productivity. With few exceptions, differences in the relative abundance of PnecC and PnecD in each sample, determined using a high-sensitivity cultivation-based approach, were due to DOM quality. These results suggest that the major DOM component in the field, which is allochthonously or autochthonously derived, is a key factor for ecological niche separation between PnecC and PnecD subclusters. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.
Shimada K.,Tokyo University of Agriculture and Technology |
Shimada K.,Tokyo Metropolitan Research Institute for Environmental Protection |
Shimada M.,Tokyo University of Agriculture and Technology |
Takami A.,Japan National Institute of Environmental Studies |
And 5 more authors.
Aerosol and Air Quality Research | Year: 2015
This study investigated the source categories and emission areas of carbonaceous aerosols transported from East Asia to the East China Sea. Mass concentrations of heavy metals, ionic components, organic carbon, and elemental carbon (EC) were measured at the Cape Hedo Atmosphere and Aerosol Monitoring Station in Okinawa, Japan, throughout 2010. The relative influences of different categories of aerosols were determined by positive matrix factorization, and the source regions of each emissions category were evaluated by using the total potential source contribution function. Five source categories were identified: dust, sea salt and nitrate, secondary species, coal combustion, and oil combustion. The results showed that the major source of aerosols in North China is coal combustion, whereas the major source in South China, Japan, and Korea is oil combustion. The relative contributions of the five sources to EC concentrations at Cape Hedo were dust 7.0%, sea salt and nitrate 19.1%, secondary species 28.5%, oil combustion 12.8%, and coal combustion 32.6%. In particular, wintertime coal combustion in residential areas of North China contributed significantly to EC in 2010. The results also indicate that the contribution of coal combustion in source areas was higher in winter (52%), whereas the contribution of oil combustion was higher in spring (33%). © Taiwan Association for Aerosol Research.
Hijioka Y.,Japan National Institute of Environmental Studies |
Takano S.,Chiyoda Corporation |
Oka K.,Chiyoda Corporation |
Yoshikawa M.,Chiyoda Corporation |
And 3 more authors.
Regional Environmental Change | Year: 2015
The impacts of climate change are apparent in various regions of the world. Even though climate change may have a positive effect, it is anticipated that there will be many severely negative effects on human and natural resources in the future. Therefore, in addition to the need for stronger promotion of mitigation policies, it is urgently necessary to study and implement adaptation policies over the longer term to prepare for the possible negative impact of climate change. To implement climate change adaptation measures rapidly in Japan, it would seem practical and effective to make good use of the various countermeasures already promoted by both the national and the local governments for many sectors such as disaster prevention, environmental management, food production, and protection of the nation’s health. These countermeasures are considered to have potential for effecting climate change adaptation. This study, focusing on adaptation to climate change negative impacts, investigates to what extent the existing policies of the Tokyo Metropolitan Government could contribute to climate change adaptation, based on a comprehensive examination of targeted fields and indicators for which adaptation policies could be pursued. The results showed many of the existing policies could be useful for adaptation to climate change in many sectors. Furthermore, less than half of these policies need to take future climate change into account in order to contribute to climate change adaptation. This study proposes three basic steps that consider future climate change and local governmental propositions for the rapid implementation of adaptation policies in Japan. © 2015 Springer-Verlag Berlin Heidelberg
Akasaka I.,Tokyo Metropolitan Research Institute for Environmental Protection
International Journal of Climatology | Year: 2010
This study investigated interannual variations in seasonal march of rainfall in the Philippines by revealing onset and withdrawal pentads of rainy seasons from 1961 to 2000. For defining the onset and withdrawal of rainy season, the empirical orthogonal function (EOF) analysis was applied. As a result, the onset of summer rainy season, when started in mid-May on the average, was frequently delayed and fluctuated more greatly after the latter half of the 1970s. Such characteristics were not found in the onset of autumn rainy season, which corresponds to the increase in rainfall amount on the east coast. To clarify causes of the long-term change in the onset timing of the summer rainy season, we classified transition patterns of atmospheric circulation related to the onset of the summer rainy season by applying the EOF analysis to spatial anomalies of geopotential height at 850 hPa level. The first two dominant EOF modes showed three important triggers of the onset of the summer rainy season in atmospheric circulation: (1) the northeastwards shift in the subtropical high over the western North Pacific, (2) the evolution of the monsoon trough over the northern South China Sea and (3) the great approach of the easterly wave. Additionally, interannual variations in the time coefficients of EOF1 have a positive tendency on the boundary of the latter half of the 1970s and are significantly correlated with those in the onset of the summer rainy season. That is, it was suggested that the change of the onset timing in the summer rainy season after the latter half of the 1970s was related to a long-term change in transition patterns of atmospheric circulation connected with the onset of the summer rainy season. © 2009 Royal Meteorological Society.
Iwase Y.,Nippon Telegraph and Telephone |
Iwase Y.,Tokyo City University |
Kondo Y.,Tokyo City University |
Fujiwara T.,Tokyo Metropolitan Research Institute for Environmental Protection
AIJ Journal of Technology and Design | Year: 2011
Cooling system had been installed for all metropolitan high schools in 2008 to improve indoor thermal condition and to increase learning efficiency of students. On the other hand IAQ problem may occur if windows are closed and mechanical ventilation is not operated. It is reported that low indoor humidity activates influenza virus. In this paper, indoor CO2 concentration and humidity are discussed on the basis of measured data in classrooms of high school. Furthermore, CFD simulation was conducted to study appropriate HVAC system to prevent influenza infection.