2001 Fiscal Year Final Research Report Summary
Evaluation of Vertical Fluxes of Nitrogen Oxide to the Troposphere from the Wide Land Surfaces
| Project/Area Number |
12680516
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | Tohoku University |
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Principal Investigator |
YASUDA Nobuhisa Graduate School of Science, Tohoku University, Professor, 大学院・理学研究科, 教授 (30004419)
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| Co-Investigator(Kenkyū-buntansha) |
SHA Weiming Graduate School of Science, Tohoku University, Associate Professor, 大学院・理学研究科, 助教授 (60251716)
YAMAZAKI Takeshi Graduate School of Science, Tohoku University, Associate Professor, 大学院・理学研究科, 助教授 (80220317)
IWASAKI Toshiki Graduate School of Science, Tohoku University, Professor, 大学院・理学研究科, 教授 (80302074)
HOJO Sachiko Shokei Women's Christian College, Department of Human Relations, Professor, 人間関係科, 教授 (90005033)
MATSUSHIMA Dai Graduate School of Science, Tohoku University, Assistant Professor, 大学院・理学研究科, 助手 (50250668)
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| Project Period (FY) |
2000 – 2001
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| Keywords | nitrogen oxide / minor gaseous constituents / turbulent transfer / urban canopy / model of heat budget / model of heat budget in the snowy area / urban atmospheric boundary layer |
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| Research Abstract |
The vertical fluxes of nitrogen oxide (NOX) including nitrogen dioxide (NO2) and nitrogen mono-oxide (NO) to the troposphere from the wide land surfaces in Miyagi Prefecture and the neighborhood areas have been hourly estimated during 8 years (1991-1998). The fundamental studies were composed of the experimental observations of NOX vertical profiles, the theoretical analyses and the researches of vertical static stabilities in the urban area. The vertical profiles of NOX were measured at the main street of 27 m-width in the urban area of Sendai City. The volumetric summations NOX of NO2 and NO are conserved in the urban canopy layer and the vertical profiles of NOX in the street canyon were clarified to have two layers by the measurements and the theoretical studies of turbulent transfers of NOX. The vertical profiles of NOX density in the upper layer have a logarithmic shape being represented by the nearly first-order equation of Inz where z is the height from the road surface. In the
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lower layer the density of NOX is nearly constant independent of the height. The transitional height of the logarithmic layer and the constant layer is about z=1〜2 m. The theory of vertical transfer of NOX were formulated. The estimation methods of friction NOX-density were introduced and the values of friction NOX-density were calculated from the data of the routine NOX-observatories controlled by the government and the prefectures. The friction velocities and the static stability were calculated from the observational data of official meteorological observatories by use of the new theoretical heat-budget model improved in the present research project in which the differences between urban canopy and the urban canyon and the roles of snowfall and the snow cover are considered. The vertical fluxes of NOX were hourly calculated with the values of the friction NOX-density and the friction velocity.
The averaged fluxes transformed into NO2 mass during 8 years were 625 kg per one year and per the road area of 27 m X 100 m at the roads considered as the source site of NOX and the averaged values were decreased in about one third of those at the roads in the urban area being far away from the roads. Less
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