Study of Urban Heat Island in Yogyakarta City Using Local Climate Zone Approach

Abstract

Yogyakarta urban area has increased significantly for the past ten years and altered ecological features, such as inducing urban heat island (UHI). Our objectives are examining UHI characteristics in Yogyakarta urban with atmospheric variables which include air temperature and relative humidity and analyzing the UHI distribution using the LCZ method. This study uses the LCZ classification to spatially compare thermal characteristic and explain how land use and building geometry affect UHI. The system comprises 17 standard classes at the local scale, using quantitative approach which includes numerical data, such as aspect ratio, building heights, and street canyons to support the classification system. Three LCZ classes found in Yogyakarta urban area are LCZ 3, LCZ 5, and LCZ 6. The LCZ variables which affect temperature and relative humidity are building heights, width of street canyons, and land use. The biggest thermal difference is ΔLCZ3-LCZ5 and ΔLCZ3-LCZ6, which happened during 08.00 – 12.00 and 16.00 – 20.00. Small UHI magnitude (< 2K) is affected by small difference in morphology and fabric. Medium UHI magnitude (2 – 5K) is mostly caused by large difference in fabric and small difference in morphology. In the future, the LCZ should be widely applied for urban planning regarding climatic mitigation.