A simple approach for the development of urban climatic maps based on the urban characteristics in Tainan, Taiwan.

Motivated by the increasing thermal load in urban environment, this work established Urban Climatic map (UCmap) focusing on thermal environment issues based on urban development factors, e.g., land cover and building characteristics, representing thermal load of human body and ventilation path in the urban structures. In the established process of UCmap in this work, Tainan city, which is a highly developed city in southern Taiwan, is selected as the research area. A 50-m resolution grid is used to capture urban development factors and the climate data based on 1 year of mobile and fix-point measurements, from which the thermal load and the wind environment map are constructed. The results herein reveal that a higher urban development level is associated with a higher thermal load, and similar areas are more likely than others to suffer from an extreme thermal load and low wind pass conditions. Open and sparse low-rise buildings constitute the most appropriate urban characteristics for urban built environment in Tainan. By the simple approach of establishing UCmap, the microclimate condition and development intensity of regions can be easily detected and linked, for example the compact high-rise areas should be limited by floor area ratio in order to prevent the formation of hot spots. The government, urban planners, and architects without a meteorological background can efficiently obtain climate information by way of mapping the certain area, and making regulations to mitigate the growing problem of thermal stress and urban heat island.