An Overview: Special Issue on "Urban Climate"
Journal of Geography (Chigaku Zasshi)
This special issue brings together the latest scientific papers on the urban climate including urban heat islands (UHI) , which have been researched by urban climatologists in Japan. However a large number of papers have been published mainly by urban technology researchers in the fields of architecture and civil engineering for the purpose of contributing to the mitigation strategies for urban heat islands promoted by central and local governments. The reason for this is explained by
... s in research motivations and methodologies between scientists and technologists. Most urban climatologists are interested in the phenomena themselves and in the mechanisms of urban climates, such as observed and simulated temperature patterns in large cities and their formation mechanisms in terms of surface energy balance systems. On the other hand, urban technology researchers are mostly interested in technological developments and innovations that can be applied in mitigation strategies such as roof-top gardens and water retainable road materials, which could efficiently decrease surface temperatures on hot summer days. Both approaches are required to mitigate urban heat islands in large cities, where heat stress patients due to extremely high temperatures in summer are increasing and local torrential rainfalls triggered by summer heat islands are occurring more frequently than before. The papers included in this special issue are summarized as follows: Nakagawa (2011) reviews trends in studies on the formation mechanism of the urban heat island in Japan with special emphasis on the relationships between urban heat island intensity (UHI) and boundary layers of urban areas. Kusaka (2011) reviews urban climate studies using the Weather Research and Forecasting (WRF) model with a brief description of WRF and three urban parameterization schemes in WRF. Watarai et al. (2011) present a numerical simulation of the rapid rise of the surface air temperature in the Northwestern Kanto Plain on 20 February, 2009 using the WRF model. The results show that the temperature rise was mainly brought about by a downward wind with adiabatic heating over the area. Akasaka et al. (2011) describe a high-spatial density meteorological observation system in Tokyo named METROS, and clarify temporal and spatial characteristics of the thermal environment of Tokyo based on METROS. Mikami et al. (2011) briefly introduce high-resolution temperature ob-