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

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.     

A method for locating potential tree-planting sites in urban areas: A case study of Los Angeles, USA

A GIS-based method for locating potential tree-planting sites based on land cover data is introduced. Criteria were developed to identify locations that are spatially available for potential tree planting based on land cover, sufficient distance from impervious surfaces, a minimum amount of pervious surface, and no crown overlap with other trees. In an ArcGIS environment, a computer program was developed to iteratively search, test, and locate potential tree-planting sites by virtually planting large, medium and small trees on plantable areas, with large trees given priority as more benefits are expected to accrue to them. A study in Los Angeles, USA found 2.2 million potential planting sites, approximately 109.3 km² of potential tree canopy cover.     

A gradient analysis of urban landscape pattern: a case study from the Phoenix metropolitan region,Arizona, USA

Landscape Ecology - Urbanization is arguably the most dramatic form of land transformation that profoundly influences biological diversity and human life. Quantifying landscape pattern and its...     

Variations in land surface temperature and cooling efficiency of green space in rapid urbanization: The case of Fuzhou city,China

Rapid urbanization has caused significant land cover change (LCC) as well as changes in the land surface temperature (LST). However, the crucial land dynamic process, which could significantly contribute to the increase in LST and aggravation of the urban heat island (UHI) effect, remains poorly understood. Additionally, a strategy to optimize the most significant decreased land cover type in order to maximize the cooling effect is still lacking. Therefore, in this study, we selected the rapidly urbanizing and ‘hottest’ city in China, Fuzhou, as a case study. Two algorithms were selected to compare and obtain reliable LST data. A land use transfer matrix was used to detect critical contributions leading to the LST variations. The concept of cooling efficiency (CE) and the threshold value of efficiency (TVoE) are also proposed, defined, and calculated. The results show that LST values increased with increasing proportion of built-up land and sharply decreasing proportion of green space. Areas where LST differences exceed 4 °C cover 93% of the areas where green spaces decreased. Additionally, the LST variation is not only associated with the dominant land cover types but is also affected by the land cover transfer pattern and dynamics. Finally, we have calculated the TVoE of green space in Fuzhou city to be 4.55 ± 0.5 ha. This finding implies that when Fuzhou municipality implements urban/landscape planning, a green space area of 4.55 ± 0.5 ha is the most efficient to reduce the heat effect. This study extends the current understanding of LCC dynamics and LST variation. The concepts of the CE and TVoE are meaningful for landscape planning practice and can be used in other cases.