Distribution and formation of the abnormal heat island in Guiyang, southwestern China

Abstract

An abnormal heat island, in which genesis is totally different from that of a normal heat island, exists in typical karst city Guiyang in southwestern China and dominates its regional thermal environment. Based on Landsat enhanced thematic mapper plus images and moderate-resolution imaging spectroradiometer land surface temperature products, the abnormal heat island in this area is accordingly extracted. Through overlaying and statistic analysis in geographic information system, this paper studied the relationship among the abnormal heat island and karst distribution, vegetation coverage, and temperature difference at day and night with the following results: nearly 70% of the abnormal heat island distributes in karst and semi-karst areas, 95.7% of abnormal heat islands mainly distribute in region of low-vegetation coverage (percentage of vegetation lower than 45%); 82.28% of abnormal heat islands are in regions where the temperature difference between day and night is over 14°C. The results show that the formation of an abnormal heat island largely depends on rock types and the area of bare rock.