Quantifying the seasonal contribution of coupling urban land use types on Urban Heat Island using Land Contribution Index: A case study in Wuhan, China

Abstract Urban Heat Island (UHI) is an urban climate phenomenon which is expected to respond to the change of urban environment and land use types in the future. UHI is closely related to urbanization and urban land use changes, since the expansion of impervious surface greatly affects the thermodynamic properties of the underlying surface. New ways to measure and assess the inner quantitative relationship between land use types and UHI are thus critical to answer the questions in this field. This paper presents a new method for better quantifying the contribution of respective land use type on UHI with the proposed Land Contribution Index (LCI). Seasonal thermal contribution of each land use type to UHI can be calculated based on the difference in average temperatures between a certain land use type and the entire study area. The experiment was conducted in Wuhan, China during 2005–2015 when the city was in rapid urbanization. Results indicate that the UHI effect has become more prominent in areas of rapid urbanization in the study area, and strong UHI (including high level and extremely high level) accounted for 8.56% of the whole region in 2015 compared with 2005 (3.35%). In addition, through analyzing temporal and spatial patterns of the distribution of UHI, increasing UHI areas were mainly distributed in the central and western parts of the city during 2005–2009, and then migrated to the surroundings from 2011. Furthermore, based on the calculation of LCI, construction land had the highest contribution to the UHI effect in the summer of 2015, while water body had conversely the lowest contribution to the UHI effect in the spring of 2005. Urban green space including forest land and agricultural land had intensively negative contributions to the UHI effect, and their alleviating functions on the thermal environment were less remarkable in winter.