Kumiko Nakamichi

Moderation of Summertime Heat Island Phenomena via Modification of the Urban Form in the Tokyo Metropolitan Area

AbstractThis study investigated the moderation of the urban heat island via changes in the urban form in the Tokyo metropolitan area (TMA). Two urban scenarios with the same population as that of the current urban form were used for sensitivity experiments: the dispersed-city and compact-city scenarios. Numerical experiments using the two urban scenarios as well as an experiment using the current urban form were conducted using a regional climate model coupled with a single-layer urban canopy model. The averaged nighttime surface air temperature in TMA increased by ~0.34°C in the dispersed-city scenario and decreased by ~0.1°C in the compact-city scenario. Therefore, the compact-city scenario had significant potential for moderating the mean areal heat-island effect in the entire TMA. Alternatively, in the central part of the TMA, these two urban-form scenarios produced opposite effects on the surface air temperature; that is, severe thermal conditions worsened further in the compact-city scenario because...

An Integrated Model for Assessing Carbon Dioxide Emissions Considering Climate Change Mitigation and Flood Risk Adaptation Interaction

Planning for climate change mitigation/adaptation for enhancing urban resilience against natural disaster risks is an important issue in Japan. For such planning to be effective, studies suggest that it is important to consider the interaction (co-benefits and trade-offs) between adaptation and mitigation measures. For example, climate change mitigation and adaptation measures could be compatible if our government got people to move from flood prone areas with considering urban structure (e.g., compact city). In order to simulate the effectiveness of such interactions, we propose an integrated assessment model for carbon dioxide (CO2) emissions under several urban land-use scenarios considering (i) urban form (dispersion/compact city) (ii) urban resilience (adaptation to flood risks) and (iii) diffusion of electric vehicles (EVs) and photovoltaic (PV) panels at a local town level in Tokyo. The developed model can be used to evaluate the co-benefits of both mitigation and adaptation measures from the viewpoint of CO2 emissions. Indirect emissions based on households’ expenditure are also estimated in addition to direct emissions. The obtained results suggest that climate change mitigation and adaptation can generate a synergistic effect from the viewpoint of CO2 emissions.