Explorations on cooling effect of small urban linear park design in low-rise, high-density district: The case of Gyeongui line forest park in Seoul

Various types of urban parks provide a nature-based solution for mitigating urban heat islands and the cooling effect of urban parks has been extensively studied. However, there is a scarcity of cases involving small linear parks based on quantifiable unit, despite the expectation of their high cooling efficiency due to their unique form and characteristics. This study examined the cooling effect of urban linear park (LP) in low-rise and high-density districts with the longest urban park case in Seoul, South Korea, Gyeongui Line Forest Park, focusing on the influential factors related to park design. Thermal condition simulations and field measurements, including evaluations of thermal comfort, were conducted both inside and outside the LP. Park extensions with increased tree coverage ratio exhibit a consistent decline in thermal variables, with reductions of up to 11.25°C for mean radiant temperature (MRT), and 5.84°C for physiological equivalent temperature (PET). Peak cooling intensities are observed during the hottest time of day at 12 °C for MRT, with parallel wind further enhancing the cooling effect. In addition, LP cooling effect related to adjacent street types was investigated and appeared to be more pronounced in narrower streets. Strategies such as adding tall trees along adjacent streets and connecting cold airflows from the park to a street tree corridor may help to strengthen LP’s cooling effect. While direct comparisons are limited, initial findings suggest that small urban linear parks under specific conditions have significant cooling potential, possibly comparable to or exceeding that of other similar-sized small urban parks, needing further investigation.