di saBatino, JunXia dou, daniel r. dreW, John M. edWards, JoaChiM fallMann, krzysztof fortuniak, JeMMa gornall, toBias groneMeier, Christos h. halios, denise hertWig, kohin hirano, alBert a. M. holtslag, zhiWen luo, gerald Mills, Makoto nakayoshi, kathy Pain, k. heinke sChlünzen, stefan sMith, lionel soulhaC, gert-Jan steeneveld, ting sun, natalie e theeuWes, david thoMson, JaMes a. voogt, helen C. Ward, zheng-tong Xie, and Jian zhong W ith the majority of people experiencing weather in urban areas, it is critical to understand cities, weather, and climate impacts. Increasing climate extremes (e.g., heat stress, air pollution, flash flooding) combined with the density of people means it is essential that city infrastructure and operations can withstand high-impact weather. Thus, there is a huge opportunity to mitigate climate change effects and provide healthier environments through design and planning to reduce the background climate and urban effects. However, our understanding of the underlying urban atmospheric processes are primarily derived from studies of separate aspects, rather than the complete, human-environment system. Air quality modeling has not been widely integrated with aerosol feedbacks on local climate, while few city-greening scenarios have tested the impacts on boundary layer pollutant dispersion or the carbon cycle. Building design guidelines have been developed without incorporating the impact of waste heat on local temperatures, which, in turn, determines building performance. Integration of such feedbacks is imperative as they define, rather than just modify, urban climate.There is an urgent need to link processes that people experience at street level (human scale) to processes at neighborhood, city, and regional scales. As these scales have traditionally been the focus for specialists in different fields, few observation and model systems cross these scales. However, understanding the interactions between these scales is critical for the design of future parametrizations ES261OCTOBER 2017 AMERICAN METEOROLOGICAL SOCIETY | and observation networks. Although models and observational methods are emerging that permit research into scale interactions [e.g., high-resolution numerical weather prediction (NWP), large-domain computational fluid dynamic (CFD) models, remote sensing, extensive sensor networks, vertical remote sensing], an integrated approach across methodologies is currently lacking.To tackle these scale interactions requires diverse skills from a wide range of research communities. This is a daunting challenge. However, improved understanding of urban atmospheric processes such as clouds and precipitation, heat transfer, and convection would enable improvements in urban system models to provide seamless hazard prediction at all time scales. Hence, an initial focus on the meteorological aspects of the research challenge may be a more manageable problem, even though the scope is still large. As such, it was identified that within the United Kingdom there is an urgent need to devel...

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An outdoor summer study on thermal physiology along subjects' pathways was conducted in a Japanese city using a unique wearable measurement system that measures all the relevant thermal variables: ambient temperature, humidity, wind speed (U) and short/long-wave radiation (S and L), along with some physio-psychological parameters: skin temperature (T skin), pulse rate, subjective thermal sensation and state of body motion. U, S and L were measured using a globe anemo-radiometer adapted use with pedestrian subjects. The subjects were 26 healthy Japanese adults (14 males, 12 females) ranging from 23 to 74 years in age. Each subject wore a set of instruments that recorded individual microclimate and physiological responses along a designated pedestrian route that traversed various urban textures. The subjects experienced varying thermal environments that could not be represented by fixed-point routine observational data. S fluctuated significantly reflecting the mixture of sunlit/shade distributions within complex urban morphology. U was generally low within urban canyons due to drag by urban obstacles such as buildings but the subjects' movements enhanced convective heat exchanges with the atmosphere, leading to a drop in T skin. The amount of sweating increased as standard effective temperature (SET*) increased. A clear dependence of sweating on gender and body size was found; males sweated more than females; overweight subjects sweated more than standard/underweight subjects. T skin had a linear relationship with SET* and a similarly clear dependence on gender and body size differences. T skin of the higher-sweating groups was lower than that of the lower-sweating groups, reflecting differences in evaporative cooling by perspiration.

[1] Rainfall interception (RI) over an outdoor urban-scale model was investigated from the perspectives of water and energy balance. On average, RI was 6% of the gross rainfall and smaller than typical values in forests. No correlation was found between RI and gross rainfall or rainfall duration unlike the correlations found in forests. Most RI occurred in the first several hours of rainfall, and then RI rapidly decreased with time during a rainfall event. RI was dependent on the saturation deficit at the beginning of the rainfall event. The latent heat for RI was approximately balanced by heat conduction from the concrete surfaces. Differences in the canopy structure are considered as possible reasons for the different behaviors of RI between the present site and forests. Accordingly, three aspects of the canopy structure, i.e., effective wet surface area, efficiency for scalar transfer, and canopy heat capacity, are discussed.Citation: Nakayoshi, M., R. Moriwaki, T. Kawai, and M. Kanda (2009), Experimental study on rainfall interception over an outdoor urban-scale model, Water Resour. Res., 45, W04415,

Numerical weather prediction models for urban weather require various urban parameters such as urban geometry and anthropogenic heat emission. Preparing databases of these urban parameters is essential for better reproducibility of urban weather simulation. In this paper, a database of urban geometric parameters for the whole Japan is created using a detailed building GIS. This database includes average, maximum, and standard deviation of building heights, plane and frontal area indices, roughness length for momentum, displacement height, and sky view factor. Furthermore, to expand this database to areas where detailed building GIS is not well prepared, methods of estimating the surface parameters are proposed. These methods require only a global digital elevation models and aerial imagery, which are now open to public inspection and easy to obtain. The results are compared with values derived from high-resolution building heights data.