Urban Heat Island effect, extreme temperatures and climate change : a case study of Hong Kong SAR

Abstract

The Urban Heat Island (UHI) effect is analyzed using LANDSAT8 satellite data acquired on two episodes of heatwaves over Hong Kong and processed using the split-window algorithm to retrieve the Land Surface Temperature (LST) over this area. The in situ ambient air temperatures measured by a number of local weather stations of the Hong Kong Observatory were used to validate the acquired LST. Regional temperature changes for the Hong Kong area for the 21st century generated using the climate scenario generator tool MAGICC/SCENGEN and constrained to SRES A2AIM project a rise in temperatures of between +0.9 and + 5.4 °C. The results show the existence of severe UHI effects between urban and suburban localities during two severe heatwave events. Geospatial analysis of this local UHI problem quantifies how urban parks can minimize the UHI effect and a number of adaptation measures related to urban spatial planning are being recommended in view of a changing climate.