||Yoichi Kawamoto, Effect of land-use change on the urban heat island in the Fukuoka-Kitakyushu metropolitan area, Japan, Sustainability, https://doi.org/10.3390/su9091521, 9, 9, 2017.08, In coastal cities, the effect of the sea breeze in mitigating the urban heat island (UHI) phenomenon has attracted attention. This study targeted the Fukuoka-Kitakyushu metropolitan area, the fourth largest metropolitan area in Japan which is also coastal. Doppler Light Detection And Ranging (LiDAR) observations were conducted in the summer of 2015 to clarify the transition of the wind field over the targeted area. To investigate the effects on the UHI of land-use change related to urbanization, the National Land Numerical Information (NLNI) land-use datasets for Japan in 1976 (NLNI-76) and 2009 (NLNI-09) were used in the Weather Research and Forecasting (WRF) model. The results of the simulation showed that most of the northern part of the Kyushu region became warmer, with an average increase of +0.236 °C for the whole simulation period. Comparing the two simulations and the Doppler LiDAR observations, the simulation results with the NLNI-09 dataset (for the year closest to the study period in 2015) showed closer conformity with the observations. The results of the simulation using NLNI-76 showed faster sea breeze penetration and higher wind velocity than the observations. These results suggest that the land-use change related to urbanization weakened the sea breeze penetration in this area..
||Alicia Murga, Yusuke Sano, Yoichi Kawamoto, Kazuhide Ito, Integrated analysis of numerical weather prediction and computational fluid dynamics for estimating cross-ventilation effects on inhaled air quality inside a factory, Atmospheric Environment, https://doi.org/10.1016/j.atmosenv.2017.08.003, 167, 11-22, 2017.01, Mechanical and passive ventilation strategies directly impact indoor air quality. Passive ventilation has recently become widespread owing to its ability to reduce energy demand in buildings, such as the case of natural or cross ventilation. To understand the effect of natural ventilation on indoor environmental quality, outdoor–indoor flow paths need to be analyzed as functions of urban atmospheric conditions, topology of the built environment, and indoor conditions. Wind-driven natural ventilation (e.g., cross ventilation) can be calculated through the wind pressure coefficient distributions of outdoor wall surfaces and openings of a building, allowing the study of indoor air parameters and airborne contaminant concentrations. Variations in outside parameters will directly impact indoor air quality and residents’ health. Numerical modeling can contribute to comprehend these various parameters because it allows full control of boundary conditions and sampling points. In this study, numerical weather prediction modeling was used to calculate wind profiles/distributions at the atmospheric scale, and computational fluid dynamics was used to model detailed urban and indoor flows, which were then integrated into a dynamic downscaling analysis to predict specific urban wind parameters from the atmospheric to built-environment scale. Wind velocity and contaminant concentration distributions inside a factory building were analyzed to assess the quality of the human working environment by using a computer simulated person. The impact of cross ventilation flows and its variations on local average contaminant concentration around a factory worker, and inhaled contaminant dose, were then discussed..
||Yoichi Kawamoto, Effect of urbanization on the urban heat island in Fukuoka-Kitakyushu metropolitan area, Japan, Procedia Engineering, doi: 10.1016/j.proeng.2016.10.027, 16, 224-231, 2016.12, In the coastal cities, the use of the sea breeze to mitigate the urban heat island phenomenon has attracted attention. To accumulate data for the urban climate in the Fukuoka-Kitakyushu metropolitan area, the fourth largest metropolitan area in Japan and located in coastal area, numerical simulations with a meso-scale meteorological model, the Weather Research and Forecast model (WRF), and upper air observation with Doppler LIDAR were carried out in the summer of 2015, simultaneously. The results of this study suggested that the urbanization process weakened sea breeze penetration..
||Yoichi Kawamoto, Effect of Urbanization on the Urban Heat Island in Fukuoka-Kitakyushu Metropolitan Area, Japan, Procedia Engineering, https://doi.org/10.1016/j.proeng.2016.10.027, 169, 224-231, 2016.01, In the coastal cities, the use of the sea breeze to mitigate the urban heat island phenomenon has attracted attention. To accumulate data for the urban climate in the Fukuoka-Kitakyushu metropolitan area, the fourth largest metropolitan area in Japan and located in coastal area, numerical simulations with a meso-scale meteorological model, the Weather Research and Forecast model (WRF), and upper air observation with Doppler LIDAR were carried out in the summer of 2015, simultaneously. The results of this study suggested that the urbanization process weakened sea breeze penetration..
||Yoichi Kawamoto, Fundamental Urban Morphology Analysis for Use in Urban Canopy Model , 日本ヒートアイランド学会, 9, 2, 44-48, 2014.12, For urban climate analysis, mesoscale meteorological models are widely utilized. The urban canopy models are used as sub-models of land surface models in mesoscale meteorological models to represent the effect of urban morphology in terms of kinetic effects and surface energy budgets. Normally, in an urban canopy model, buildings in an analysis mesh are assumed to be uniform. However, in reality, the buildings in any given area are not uniform; they can differ in terms of their heights, areas, and shapes. This raises the question whether the gaps between the morphologies of the presumably uniform modelled buildings and the real non-uniform buildings are significant or not. In this study, the urban morphology in Japanese cities is analyzed by the means of Geographical Information System (GIS). Some urban canopy models represent the variations in buildings’ heights based on normal distribution. However, in this study, building distribution in terms of heights reflects power-law distribution on a macro scale in entire Japan, and on a micro scale with a resolution of about 1 square kilometer..
||Xuefan Zhou, Ryozo Ooka, Hong Chen, Yoichi Kawamoto, Hideki Kikumoto, Impacts of inland water area changes on the local climate of Wuhan, China, Indoor and Built Environment, https://doi.org/10.1177/1420326X14546774, 25, 2, 296-313, 2014, A distinct feature of Wuhan is that almost a quarter of the total area of this city is covered with water, leading to its unique hot and humid climate characteristics in summer. However, according to records, water area in built-up zone of Wuhan has been reduced by 130.5 km2 from 1965 to 2008, while the annual average air temperature has been increased by more than 3°C. To investigate the quantitative connection between the water area reduction and air temperature increase, three scenarios were simulated in a summer; to evaluate the impact of water reduction on the local thermal environment in different water areas; and to study the impact of water reduction on the urban heat island (UHI) phenomenon. Meso-scale meteorological models of Weather Research and Forecasting model were applied in this study for quantitative assessment and prediction. With the predictions, this study reveals that the decreased water area could affect air temperature, wind velocity and wind flow direction, energy balance and the UHI intensity. The simulations show that areas with significant wind velocity, wind direction and air temperature differences are distributed among the downwind zones. Moreover, the areas with high UHI intensity are wider and farther from the boundary of urban areas because of the reduction of water areas..
||Yoichi Kawamoto, Hiroshi Yoshikado, Ryozo Ooka, Hiroshi Hayami, Hong Huang, Viet Nam, Sea breeze blowing into urban areas
Mitigation of the urban heat island phenomenon, Ventilating Cities
Air-flow Criteria for Healthy and Comfortable Urban Living, https://doi.org/10.1007/978-94-007-2771-7_2, 11-32, 2012.01, Currently, about 50% of the world’s population is living in urban areas, and that figure is predicted to continue to increase (United Nations, Department of Economic and Social Affairs Population Division, Population Estimates and Projections Section (2009) World urbanization prospects: the 2009 revision). On the other hand, many cities are facing problems caused by urbanization. The urban heat island phenomenon, one of the urban climate problems, is a typical environmental problem encountered in dense urban areas in summer. The use of the sea breeze to mitigate the urban heat island phenomenon has attracted attention in coastal cities. Some statistics show that about 40% of the world’s population lives within 100 km of the coast (World Resources Institute, Fisheries (2007) Population within 100 km of coast). Further investigation of the environment in the urban area near the coast is, therefore, important. In this chapter, Tokyo is targeted for investigation. Tokyo is the Japanese capital, and its surrounding region, the Tokyo metropolitan area, comprises a circular area with a radius of 50 km and a population of over 30 million. Within this area, the sea breeze from Tokyo Bay is an important factor mitigating the air temperature rise in summer. However, ongoing urbanization could be changing not only the mechanism of the energy balance on the urban surface but also the sea breeze system in the region. To clarify the effects of urbanization, a mesoscale meteorological model was adopted for analysis. Simulation results suggest that expansion of the Tokyo metropolitan area from the 1970s to the 1990s has induced a temperature rise near the ground and that the difference is largest in inland areas. Moreover, the time of sea breeze penetration is delayed in suburban areas. These results suggest that the ongoing urbanization process could raise the air temperature and change the sea breeze system in the Tokyo metropolitan area..
||C. S.B. Grimmond, M. Blackett, M. J. Best, J. J. Baik, S. E. Belcher, J. Beringer, S. I. Bohnenstengel, I. Calmet, F. Chen, A. Coutts, A. Dandou, K. Fortuniak, M. L. Gouvea, R. Hamdi, M. Hendry, M. Kanda, T. Kawai, Yoichi Kawamoto, H. Kondo, E. S. Krayenhoff, S. H. Lee, T. Loridan, A. Martilli, V. Masson, S. Miao, K. Oleson, R. Ooka, G. Pigeon, A. Porson, Y. H. Ryu, F. Salamanca, G. J. Steeneveld, M. Tombrou, J. A. Voogt, D. T. Young, N. Zhang, Initial results from Phase 2 of the international urban energy balance model comparison, International Journal of Climatology, https://doi.org/10.1002/joc.2227, 31, 2, 244-272, 2011.02, Urban land surface schemes have been developed to model the distinct features of the urban surface and the associated energy exchange processes. These models have been developed for a range of purposes and make different assumptions related to the inclusion and representation of the relevant processes. Here, the first results of Phase 2 from an international comparison project to evaluate 32 urban land surface schemes are presented. This is the first large-scale systematic evaluation of these models. In four stages, participants were given increasingly detailed information about an urban site for which urban fluxes were directly observed. At each stage, each group returned their models' calculated surface energy balance fluxes. Wide variations are evident in the performance of the models for individual fluxes. No individual model performs best for all fluxes. Providing additional information about the surface generally results in better performance. However, there is clear evidence that poor choice of parameter values can cause a large drop in performance for models that otherwise perform well. As many models do not perform well across all fluxes, there is need for caution in their application, and users should be aware of the implications for applications and decision making..
||Ryozo Ooka, Mai Khiem, Hiroshi Hayami, Hiroshi Yoshikado, Hong Huang, Yoichi Kawamoto, Influence of meteorological conditions on summer ozone levels in the central Kanto area of Japan, Procedia Environmental Sciences, https://doi.org/10.1016/j.proenv.2011.03.017, 4, 138-150, 2011.01, We investigated the influence of meteorological factors that affect ozone in summer using both measurement analysis and numerical simulation. The results show that there is a close relationship between changes in meteorological conditions and variations in ozone concentrations over the central Kanto area. In summer, up to 84% of long-term variations in peak ozone concentrations may be accounted for by changes in the seasonally averaged daily maximum temperatures and seasonally averaged wind speeds. The ozone episodes in the Kanto region are dominated by three major patterns, of which Patterns I and II are regular summertime pressure patterns with a 26% and 16% frequency of occurrence, respectively. A detailed process analysis of ozone formation under urban heat island (UHI) at two areas in the Kanto region - urban and rural area - indicates that ozone formation is mainly controlled by chemistry, dry deposition, vertical transport, and horizontal transport processes. The groundlevel ozone concentrations are enhanced mainly by the vertical mixing of ozone-rich air from aloft, whereas dry deposition process mainly depletes ozone. Horizontal transport and chemistry processes play opposite roles in the net change of ozone concentration between the two areas. The results of numerical simulations also indicate that the sea breeze has significant effects on the ozone accumulation and distribution in the Kanto area. The high ozone was first observed in urban area and then was transported to the rural area by sea breeze. At rural area, the highest ozone concentrations were found in late afternoon, about two hours later in comparison with the urban area..
||Ryozo Ooka, Taiki Sato, Kazuya Harayama, Shuzo Murakami, Yoichi Kawamoto, Thermal Energy Balance Analysis of the Tokyo Metropolitan Area Using a Mesoscale Meteorological Model Incorporating an Urban Canopy Model, Boundary-Layer Meteorology, https://doi.org/10.1007/s10546-010-9550-8, 138, 1, 77-97, 2011.01, The summer climate around the Tokyo metropolitan area has been analysed on an urban scale, and the regional characteristics of the thermal energy balance of a bayside business district in the centre of Tokyo (Otemachi) have been compared with an inland residential district (Nerima), using a mesoscale meteorological model incorporating an urban canopy model. From the results of the analysis, the mechanism of diurnal change in air temperature and absolute humidity in these areas is quantitatively demonstrated, with a focus on the thermal energy balance. Moreover, effective countermeasures against urban heat-islands are considered from the viewpoint of each region's thermal energy balance characteristics. In addition to thermal energy outflux by turbulent diffusion, advection by sea-breezes from Tokyo Bay discharges sensible heat in Otemachi. This mitigates temperature increases during the day. On the other hand, because all sea-breezes must first cross the centre of Tokyo, it has less of a cooling effect in Nerima. As a result, the air temperature during the day in Nerima is higher than that in Otemachi..
||Mai Khiem, Ryozo Ooka, Hiroshi Hayami, Hiroshi Yoshikado, Hong Huang, Yoichi Kawamoto, Process analysis of ozone formation under different weather conditions over the Kanto region of Japan using the MM5/CMAQ modelling system, Atmospheric Environment, https://doi.org/10.1016/j.atmosenv.2010.07.038, 44, 35, 4463-4473, 2010.11, We have assessed the contributions of individual physical and chemical atmospheric processes on ozone formation under different weather conditions during a typical summer month (August 2005) using the MM5/CMAQ modelling system. We found that the ozone episodes in the Kanto region are dominated by three major patterns, of which Patterns I and II are regular summertime pressure patterns with a 26% and 16% frequency of occurrence, respectively. A process analysis at two typical sites in the Kanto region - one located in the central region of Tokyo and the other located in the rural areas of Kanto - indicates that ozone formation is mainly controlled by advection, vertical diffusion, dry deposition, and chemical processes. The ground-level ozone concentrations are enhanced mainly by the vertical mixing of ozone-rich air from aloft, whereas the dry deposition and chemical processes mainly deplete ozone. By investigating the effects of each process under different weather conditions, we found that the significant decrease in ozone removal due to the chemical and advection processes under conditions of high stagnation is the most important cause of the enhanced levels of ozone in the central region of Tokyo. The results of this study can contribute to a better understanding of ozone formation in the Kanto region, and they may be valuable for local policy makers for further development planning..
||C. S.B. Grimmond, M. Blackett, M. J. Best, J. Barlow, J. J. Baik, S. E. Belcher, S. I. Bohnenstengel, I. Calmet, F. Chen, A. Dandou, K. Fortuniak, M. L. Gouvea, R. Hamdi, M. Hendry, T. Kawai, Yoichi Kawamoto, H. Kondo, E. S. Krayenhoff, S. H. Lee, T. Loridan, A. Martilli, V. Masson, S. Miao, K. Oleson, G. Pigeon, A. Porson, Y. H. Ryu, F. Salamanca, L. Shashua-Bar, G. J. Steeneveld, M. Tombrou, J. Voogt, D. Young, N. Zhang, The international urban energy balance models comparison project
First results from phase 1, Journal of Applied Meteorology and Climatology, https://doi.org/10.1175/2010JAMC2354.1, 49, 6, 1268-1292, 2010.06, A large number of urban surface energy balance models now exist with different assumptions about the important features of the surface and exchange processes that need to be incorporated. To date, no comparison of these models has been conducted; in contrast, models for natural surfaces have been compared extensively as part of the Project for Intercomparison of Land-surface Parameterization Schemes. Here, the methods and first results from an extensive international comparison of 33 models are presented. The aim of the comparison overall is to understand the complexity required to model energy and water exchanges in urban areas. The degree of complexity included in the models is outlined and impacts on model performance are discussed. During the comparison there have been significant developments in the models with resulting improvements in performance (root-mean-square error falling by up to two-thirds). Evaluation is based on a dataset containing net all-wave radiation, sensible heat, and latent heat flux observations for an industrial area in Vancouver, British Columbia, Canada. The aim of the comparison is twofold: to identify those modeling approaches that minimize the errors in the simulated fluxes of the urban energy balance and to determine the degree of model complexity required for accurate simulations. There is evidence that some classes of models perform better for individual fluxes but no model performs best or worst for all fluxes. In general, the simpler models perform as well as the more complex models based on all statistical measures. Generally the schemes have best overall capability to model net all-wave radiation and least capability to model latent heat flux..
||Yoichi Kawamoto, Ryozo Ooka, Incorporating an urban canopy model to represent the effects of buildings
Development of urban climate analysis model using MM5 Part 2, Journal of Environmental Engineering (Japan), https://doi.org/10.3130/aije.74.1009, 74, 642, 1009-1018, 2009.08, Urban heat island phenomena have been analyzed by numerous researchers using mesoscale meteorological models. Although there are many mesoscale models, MM5 is considered one of the major mesoscale models. In such analysis, a one-dimensional heat balancemodel is primarily used for surface boundary conditions. However, it is necessary to include the effect of the building canopy to analyze the thermal environment at pedestrian level. Therefore, MM5 is incorporated with the urban canopy model. The urban thermal environment in Kanto region is analyzed by means of the new method. The results show better agreement with observation data..
||Yoichi Kawamoto, Ryozo Ooka, Improvement of parameterization of ground surface andincorporationofanthropogenic heatrelease Development ofurban climate analysis modelusing MM5 Part1, Journal of Environmental Engineering (Japan), https://doi.org/10.3130/aije.73.1125, 73, 631, 1125-1132, 2008.09, Meso-scale climate analysis is very useful to understand the structure of the urban heat island. MM5, provided by National Center for Atmospheric Research, is one of major meso-scale model in the world. However, parameterization of ground surface in MM5 is rather coarse to analyze urban climate. That is, in MM5, ground surface parameters are determined by most superior land-use in each mesh. However, this method is unable to represent detail urban structure, to say, the effect of Cool Island with green or water body is neglected. In this paper, ground surface parameterization in MM5 is modified to represent land-use fraction. Furthermore, effect of anthropogenic heat release is also incorporated in MM5..
||Junichi Susaki, Supannika Pothithep, Ryozo Ooka, Yoshihumi Yasuoka, Takahiro Endo, Yoichi Kawamoto, Hidenobu Nakai, Madoka Nakashima, Rei Takada, Keiichi Okada, Extraction of parameters from remote sensing data for environmental indices for urban sustainability, 26th Asian Conference on Remote Sensing, ACRS 2005 and 2nd Asian Space Conference, ASC
Asian Association on Remote Sensing - 26th Asian Conference on Remote Sensing and 2nd Asian Space Conference, ACRS 2005, 2, 906-915, 2005.12, Asian mega cities have continued to expand, and accordingly, various problems, e.g. social, economical and environmental problems, have been widely recognized in Asia. Especially, environmental issues caused by Asian mega cities will affect not only the areas within mega cities but also the whole area of Asian countries because the effects will be widely propagated by atmospheric or marine transportation. Authors have conducted researches related to comprehensive assessment indices for urban sustainability, named as Environmental Indices for Urban Sustainability (EIUS). In the framework of EIUS, both the environmental quality and the environmental load are focused on. An urban sustainability will be evaluated based on the scores for all categories of EIUS . Most of the environmental data used in EIUS are collected from statistical data and those are restricted to point-based data. If area-based data such as vegetation distribution or urban area distribution are required, remotely sensed technique is quite useful. Remote sensing data also has an advantage to compare the parameters of different cities by the same criteria. In the present research, the applicability of remote sensing data to extract area-based environmental data for EIUS was examined. Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) images, observed in 1990s and 2000s, were used to extract vegetation index, albedo and land surface temperature. Urban areas of Bangkok in 1990s and 2000s were extracted from such parameters. Based on the acquired results, the methodology will be improved and applied to extract urban areas in other Asian mega cities..