Applicability of mobile-measurement strategies to different periods: A field campaign in a precinct with a block park

Abstract

Urban green spaces play a crucial role in regulating the micro-climates of their surrounding built-up areas, which is particularly important in high-density cities. A field-measurement method with high accuracy and convenient movement is always adopted to assess the micro-climates and regulating capacity. Compared with fixed observation, mobile measurements have been found to offer advantages such as the need for lesser manpower and instruments. Despite the role of mobile measurements in characterizing urban thermal environments, there has still been a lack of consistent methods, leading to measurement errors. Accordingly, this study aimed to assess the applicability of mobile-measurement strategies by a two-day field campaign around People's Park in Guangzhou, China. Numerous findings were noted. Mobile measurements on the precinct scale required a staying time of at least 6 min to account for the response time of the probes. Additionally, the most applicable time periods for mobile measurements were the afternoon and even the evening. In terms of thermal characterization, the optimized reentry-transect method should be adopted for periods with abrupt changes in the ambient temperatures. Lastly, the block park has been observed to exert a more substantial ‘cool island’ effect under the colder weather on both days. Its park cooling intensity (PCI) in the late summer ranged from 0.55 to 1.82 °C, with a cooling efficiency of 0.33 °C/100 m, while that in the early autumn ranged from 0.49 to 3.18 °C, with a cooling efficiency of 0.50 °C/100 m.