Abstract
The air pollution concentration in Kathmandu valley in the winter season was found to be higher than in the summer season due to the formation of the inversion layer. This mechanism was simulated in the water-tank experiment by measuring the temperature and flow field using liquid crystal thermometry and particle image velocimetry. Thermal stratification was made at the beginning of the experiment and the surface temperature of the valley model was changed with 12 minutes period matching the diurnal field temperature pattern of the Kathmandu valley. The updraft wind and Bernard convection occurred during daytime and downdraft wind and inversion layer were realized during nighttime. The temperature, flow field and mass dispersion characteristics obtained in the water-tank experiment explained clearly the mechanism of air pollution in Kathmandu valley.
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Manohar Lal Shrestha: He graduated his B. E. degree in Mechanical Engineering from Aligarh Muslim University, India in 1991 and worked at Toyota Nepal (United Traders Syndicate Pvt. Ltd., Nepal) as a Service Manager. He joined the R & D section of Fujikin Incorporated, Japan, in 1992 as an engineer. He got his M.E. degree in Environmental Engineering from graduate school of engineering, Osaka University, in 2002. Currently, he is a Ph. D. candidate in Osaka University and his research interests are atmospheric pollution mechanism, air flow measurement using flow visualization and image processing.
Kaga Akikazu: He received his B. E. degree in 1969, M. E. in 1971 in Mechanical Engineering, and his D. E. degree in 1985 in Environmental Engineering from Osaka University. He has been working in Osaka University from 1971 as an assistant professor, from 1988 as an associate professor and from 2000 as a professor. His current research interests are airflow measurement using flow visualization and image processing, and the analysis and management of air pollution problems in Asian cities.
Akira Kondo: He received his B. E. degree in 1982, and M. E. degree in 1984 and his D. E. degree in 1999 in Environmental Engineering from Osaka University. He worked in Matsushita Industrial Co. till 1989. After that, he worked as an assistant professor in the Department of Environmental Engineering in Osaka University. Currently, he is working as an associate professor and his research interests are numerical simulation model of atmospheric boundary layer and environment management in South-East Asia.
Yoshio Inoue: He received his B. E. degree in 1973 in mechanical engineering from Osaka Institute of Technology and his D. E. degree in 1999 in Environmental Engineering from Osaka University. He has been working in Osaka University from 1971 as a technician and as an assistant professor from 1988. His current research interests are airflow measurement using flow visualization and image processing, and automatic recognition of aerosol particles such as asbestos fibers and allergic pollens from microscopic image of specimen using image processing.
Masahiko Sugisawa: He graduated his B.E. degree in Environmental Engineering from Osaka University in 2002 and is currently a master student in the same University and his research interests are atmospheric pollution mechanism, air flow measurement using flow visualization and image processing.
Balkrishana Sapkota: He received his M. Sc. (Physics) from Tribhuvan University, Nepal in 1980, M. Tech. (Hydrology) from University of Roorkee, India in 1984 and got the Ph. D. from same University in 1988. He joined Trichandra College, Tribhuvan University (T.U.) as an Assistant Lecturer in 1981. He moved to Institute of Engineering, T.U. to work as a Lecturer in 1988. Currently, he is working as a associate professor at Institute of Engineering, Nepal. His research contributions include measurement/analysis of Air pollutant, Noise Pollution and development of Global Circuit Model to study the variation of atmospheric electrical parameters due to variation in air pollutant.
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Shrestha, M.L., Kaga, A., Kondo, A. et al. Simulation of winter air pollution dispersion mechanism of Kathmandu valley by water-tank experiment. J Vis 7, 317–329 (2004). https://doi.org/10.1007/BF03181536
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DOI: https://doi.org/10.1007/BF03181536