Chun Liang Tan

Influence of Water bodies on Outdoor Air Temperature in Hot and Humid Climate

Water features, within an urban area have a positive effect on the microclimate of the surrounding areas when natural cooling from evaporative process is needed in the hot sunny day. The increased availability of water usually enhances evaporation, and the associated uptake of latent heat provides and additional daytime cooling effect. The water bodies of the river operate as the cooling source on the microclimate of the surrounding area. Air temperature near or over bodies of water is much different from that over land due to differences in the way water heat and cool. Water bodies are noted to be about the best absorbers of radiation, but on the other hand, they exhibit very little thermal response. Many other researches argued that evaporative cooling from water bodies or water features is yet one of the most efficient ways of passive cooling for building and urban spaces. However, evaporative cooling may not work optimally in a hot humid tropical country due to its relatively high humidity. This paper studies the evaporative cooling performance of a waterway of approximately 70m to its surrounding micro-climate. The waterway is situated in Kallang, Singapore. The air temperature and relative humidity are measured continuously for five months, May and September 2010, to find the clear extent of the cooling effect from the waterway horizontally. There is a total of 10 measurement points in each location, where five points of measurement are located along the waterway and another five points of measurement are located moving away from the waterway in order to observe the extent of its cooling effect.

Plant Selection and Placement Criteria for Landscape Design

This study explores how landscape design can be optimized by considering specific plant traits and their corresponding temperature reduction potential. An initial study was conducted with the aim of quantifying the impact of rooftop greenery on mean radiant temperature (T mrt ). Results show that under clear sky conditions, plots with vegetation can reduce surrounding T mrt by up to 6.0 °C. The effect in temperature reduction is evident for a distance up to 3.0 m away from the center of the green plots. Thereafter, a second set of measurements was made to identify specific plant traits that contribute to temperature reduction. Results indicate that the temperature reduction potential of different types of vegetation varies according to their physical characteristics as well as physiological attributes such as plant evapotranspiration rate and shrub albedo. An empirical model was developed to establish the relationship between T mrt reduction, plant evapotranspiration and shrub albedo. Findings from these studies are used as a basis to formulate a framework for landscape planning and design. In the proposed framework, vegetation as well as building information are superimposed using a Geographical Information Systems (GIS) platform. A hypothetical scenario is used to illustrate the efficacy of the proposed landscape planning framework.

STEVE Tool: Bridging the Gap between Urban Climatology Research and Urban Planning Process

In the past decades, urban heat island (UHI) phenomenon in the city and its corresponding issues including the mitigation methods have become the main research topics in the area of urban climatology. Researchers have conducted various investigations and measurements in which as the results, they have come out with various prediction models for different purposes. Nevertheless, these prediction models are too complicated for educated non-scientists, in this case the urban planners. At the end, these models remain in the academic domain, unless the scientists are engaged and involve in the urban planning process. There is a gap between scientists and planners. The Screening Tool for Estate Environment Evaluation (STEVE) has been developed as an effort to bridge between urban climatology research, in this case the urban temperature, and urban planning process. In the near future, the STEVE Tool will become an interactive design tool where the urban planners design the building massing and do the urban temperature prediction at the same platform and time. This paper also discusses the prospective of urban climatic analysis tool that lies on how to analyze the interaction between buildings and their surrounding environments as an integrated urban design process.