Quantifying the Impact of Land use/Land Cover Changes on the Urban Heat Island: A Case Study of the Natural Wetlands Distribution Area of Fuzhou City, China

In this paper, the natural wetlands distribution area (NWDA) of Fuzhou city was selected as a case study for quantifying the impact of land use/land cover (LULC) changes on patterns of the urban heat island (UHI) and characterizing wetland thermal properties in response to rapid urbanization from 1989 to 2009. The results show that dramatic changes in LULC have occurred that have drastically altered the land surface characteristics and spatiotemporal patterns of the UHI. Additionally, wetland degradation due to strong pressure from urban encroachment and its effect on the thermal properties of wetland landscapes was observed. Fragmented wetland patches of small sizes always exhibit high land surface temperatures (LST), but aggregated patches of larger sizes exhibit lower and more stable LST. The area of wetland patches characterized by a relatively low LST (< 20 A degrees C) decreased markedly over the time period studied. Furthermore, there is a significant linear relationship between patch size and the area of wetland with low LST. According to temporal analysis on inter-annual variations of UHI intensity (UHII), the built-up land exhibited the highest temperature. Spatially, there were significant LST gradients from the city center to the surrounding peri-urban and rural areas.