Microclimate Variations in Urban Green Spaces Depending on Site Characteristics

Abstract

Urbanization affects the urban environment by replacing natural areas with artificial surfaces. Simultaneously, when the climate of a region interacts with the local landscape, a unique microclimate is created. Such microclimates affect ecosystem processes, human comfort, and energy consumption. However, microclimates are often ignored in landscape planning due to an insufficient understanding of the interaction between their functions and the landscape configuration. In this regard, this dissertation investigates how the microclimate varies in urban green spaces and how it functions depending on site characteristics. <br/> First, Chapter 2 studied the spatial and temporal patterns of microclimates at an urban forest edge. Fragmented forests generate a variety of forest edges, leading to microclimates in the edge zones that differ from those in the forest interior. Understanding microclimatic variation is an important consideration for managers because it helps when making decisions about how to restrict the extent of edge effects. Thus, this chapter attempted to characterize the changing microclimate features at an urban forest edge located on Mt. Gwanak, Seoul, South Korea. The edge effects on air temperature, relative humidity, soil temperature, soil moisture, and photosynthetically active radiation (PAR) were examined during the hottest three consecutive days in August 2016. Results showed that each variable responded differently to the edge effects. This urban forest edge had an effect on temporal changes at a diurnal scale in all microclimate variables, except soil moisture. In addition, all variables except relative humidity were significantly influenced by the edge effect up to 15 m inward from the forest boundary. The relative humidity fluctuated the most and showed the deepest extent of the edge effect. Moreover, the edge widths calculated from the relative humidity and air temperature both peaked in the late afternoon (16:00 h). The findings provide a reference for forest managers in designing urban forest zones and will contribute to the conservation of fragmented forests in urban areas.<br/> Second, Chapter 3 demonstrates the comparisons of vegetation arrangement to improve microclimate and thermal comfort. Appropriate microclimate design for urban parks is important, as it impacts on human sensation and thereby influences utilization of outdoor spaces by the public. Modifying the vegetation arrangement can improve the microclimate, especially under hot season conditions. However, it is difficult to measure microclimatic variations in the individual components within a park. Therefore, this study combined in-situ measurements and a three-dimensional microclimate model ENVI-met, to examine variations in the microclimate of an urban neighborhood park in Seoul, Korea. Different vegetation arrangements were investigated with respect to their effects on microclimate and thermal comfort on a typical summer day. Results showed that: 1) the simulated results of ENVI-met were similar to the observed data, with an index of agreement of 0.69–0.88