Abstract
This study investigated effects of rooftop greening on moderating air temperature in Tokyo metropolitan area, by numerical simulation using realistic scenarios based on "nature conservation ordinance" enacted by Tokyo metropolitan government. This study was conducted by using Weather Research and Forecasting (WRF) model and NCEP Final Analysis da ta as initial and boundary conditions. The simulated case was 4th August, 2006 that was a typical cl ear summer day. As a result, in case of rooftop greening area ratio of 100%, air temperature dropped as much as about 0.7 degrees in the 23 wards of Tokyo on average. Moreover, air temperature dropped as much as about 0.3 degrees on average in case of rooftop greening area ratio of 35%, provided by the maximum greening ratio of "nature conservation ordinance" above. Additionally, this study converted an amount of decreasing air temperature into the decrease of CO2 emissions. The reduction of CO2 emissions was about 11-32 thousands t/month in August, which corresponds to about 1.1-3.5% of the amount of CO2 emissions in Tokyo.
