Urban green infrastructure planning methods to mitigate urban heat island impacts and associated nighttime temperatures using Landsat 8 data

Abstract

This study’s hypothesis is that large heat islands can be fragmented through the use of open space, which allow flows of cool air to reduce night-time temperatures. Using data from Landsat 8, a four-step method, comprising data collection, data analysis, decision making and final planning, is proposed to enable planning for mitigation of urban heat island effects. (1) Land cover and existing daily surface air temperature maps were generated from the Landsat 8 data and summer observatory data from the Meteorological Agency. (2) Surface temperature and air temperature (at 0500 hours) maps were derived using a formula incorporating the ratio of green space within different spatial scales within the survey areas. (3) Predictive maps of surface temperature and air temperature (at 0500 hours) were generated using three alternative green space plans (focused along riversides, streets and in school grounds, respectively), using the same formula. (4) This scenario appraisal approach can contribute to new green infrastructure planning to mitigate the increasingly important issue of urban heat island impacts and night-time temperatures.