Assessing the impacts of urbanization-associated green space on urban land surface temperature: A case study of Dalian, China

- Urban green space decreased remarkably, land surface temperature increased and thermal environment deteriorated during rapid urbanization.
- The main reason of LST increased is urban green space was converted to other land use types, especially is neighborhood green space reduction.
- The role of urbanization in the increase and aggregation of high-temperature areas, as evidenced in the city center, as well as in the reduction and fragmentation of low-temperature areas, as shown in the urban fringe areas.

Taking Dalian City as the study area, the spatial distribution of urban green space and land surface temperature (LST), as well as their evolution in 1999, 2007 and 2013, were obtained through remote sensing (RS) interpretation and inversion. Landsat ETM and SPOT data were used for this purpose. By combining the temperature and vegetation index models (TVX), the effects of urban green space reduction on the thermal environment during city development were evaluated. The results show the following. (1) During 1999-2013, 88.1 km2 of urban green space was converted to other land uses, accounting for a 29.4% reduction in urban green space in the study area. (2) During the study period, the LST in this area increased by +8.455 K. The evolution of the regional thermal landscape can be characterized by increases in the LST, greater complexity of the thermal landscape structure, increase and aggregation of high-temperature areas, and reduction and fragmentation of low-temperature areas. (3) During the process of urbanization, urban green space with low land-surface temperature was converted to other land use types with high land-surface temperature. When development occurred at the price of urban green space, negative effects on the regional thermal environment were observed.