| Beijing's Greenbelt is an important content of the "Scattered-Groups"layout strategy of Beijing. As a kind of green space, Beijing's Greenbelt alsoplays an important role in improving urban ecological environment. Meanwhile,developing Beijing's Greenbelt is extremely intricate and comprehensive, ofwhich the plan strategies should be a series of measures covering multiple fields.As urban thermal effect has been coming to be an increasingly serious problemto Beijing, this paper researches on how to make full use of existing and limitedGreenbelt to improve conditions, and highly focuses on Beijing's Greenbelt planning strategies for the mitigation of urban surface thermal effect.In need of study, we chose three Landsat5TM images, respectivelyachieved on Sep7th,1992, Aug31st2001, and Aug2nd,2008. Via remotesensing and GIS analysis, we retrieved land surface temperatures inexperimental areas and extracted information of the green patches. We find thatsurface thermal effect of Beijing deteriorated rapidly after the1990s,characterized by redistribution of surface urban heat island from northern areato southern area and from central city to new towns. Greenbelt improves surfacethermal environment efficiently as indicated by surface thermal analysis atmultiple time and spatial scale. Through statistical analysis, we further find thatNDVI, area, perimeter and shape index are important dimensions affecting greenpatches' cooling effect. These results are confirmed by meteorologicalobservation, greenbelt statistics and previous researches.Based on these results, we carried out our planning strategies to mitigatethe surface thermal effect by increasing the vegetation coverage, area, perimeterand reducing the shape index of green patches within Beijing's greenbelt. Butthe implementations of those measures are highly depended on greenbelt's scale.The case of the Olympic Forest Park had conducted a preliminary validation forthe planning strategies.
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