| Along with the accelerating growth of global climate variation and urbanization, disaster has already become a significant challenge for social development. Being a huge hazard bearing body, city, a high concentration of population and economy, has increasingly drawn more attention from international society and states on its strength of preventing and fighting calamities. As a space body of special form, urban green space has comprehensive social and ecological benefit, and with its inherent capacity of disaster prevention and reduction, it can play an important role in meeting emergency and avoiding disaster while facing assorted urban calamities so as to enhance the collective ability of avoiding disaster of the whole city.First, through consulting large number of literature data, this paper analyzed existing theory and practical results at home and abroad comprehensively, pointing out the necessity and importance of urban green space performing its sheltering function and affirming the concept of green land for disaster prevention. In this paper, function of urban green space for emergency had been divided into three stages of defense before disaster, meeting emergency during disaster and recovery after disaster, and specific function, feature, type and level of the three stages have been discussed.Second, based on analysis, summarization mentioned above and expansive experiences of domestic and overseas, this paper tried to choose corresponding indexes as influencing factors from19aspects:regional advantage, regional availability, service capacity, urban green land diversity, uniformity, fragmental degree, architecture distribution, transportation capacity, difficulty of disaster relief, fireproof capacity, medical capacity, safety, living convenience of avoiding disaster, Survival support capacity, political situation, social situation, economic situation, natural condition and degree of being emphasized.Third, selection principle and calculating approaches like professor consulting method and AHP had been confirmed to establish hierarchical structure based on factors mentioned above on which index weights and their sorting were obtained by using mathematical methods such as expert consultation and ahp. First introduction of landscape pattern coefficients, regional administrative levels, social undertakings investment, etc. as indexes improved and quantified the system of evaluation of sheltering capacity of urban green space.Fourth, by combining grading method and fuzzy comprehensive evaluation method, evaluation index system and model of assessing sheltering capacity of urban green space was constructed in order to provide theoretical and practical support for reducing the negative impact brought by urban calamities.Last, this paper took green space in Guangzhou as an example and SPOT-5image in2009as data sources, on which using software like ARCGIS to do GIS special analysis and Geostatistical analysis so that the green space information in different districts in Guangzhou can be extracted, classified and visualized. Combined with data from Guangzhou Yearbook of2009and meteorological data from2002to2009in Guangzhou, each index involved in evaluation system of sheltering function of urban green space was calculated and the existing distribution and realization status of green land in every region in Guangzhou were compared with each other. The results proved that this system was scientific and rational reaching the target of using theory to conduct practice commonly.This paper was hoped to improve the relative theory on sheltering function of urban green space and provide some reference for urban planning and construction in Guangzhou or other cities in days to come. |
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