Earth Surface Processes
WANG Fa-zeng, WANG Sheng-nan, LI Meng
Optimization of green open space plays a significant role in achieving sustainable development of ecological cities.Green open space system in Luoyang consists of 6 categories: product green area,farmland and forest,riparian area,garden,road landscape area and auxiliary green area.By using landscape pattern analysis,Structure Evenness Radio Index,Ecological Intensity Index,and Huff model,the paper examines the dynamic changes in area,shape and distribution of the green open space from 1988 to 2008.It evaluates service capacity of the green open space system before spatial distribution and demand-supply condition is optimized.Results are shown as follows.1) For the 20 years there is an increase in riparian areas,gardens,road landscape areas and auxiliary green areas,while a decrease in product green area,farmland and forest.Green space is abundant in Quadrants 2-5 and Rings 4-8,and less in Quadrants 7 and 8 and Rings 1,2,and 10.2) There are significant differences in Evenness Radio of all quadrants and rings.However,Quadrant 6 and Ring 5 show stable Evenness Radio,indicating gradual improvement of green space distribution in riparian areas,gardens,road landscape areas and auxiliary green areas.3) There is a notable increase in density of green patches,with areas along the Luohe River and west fringe of the city having the highest value.Many green patches have low Shape Index,though some regions see an increase.The patches generally display regular geometry shapes,which are obvious products of urban planning.4) Ecological Serving Intensity Index of 2008 is 0.288,and falls into Class III,being an ordinary level.Time costs for local residents visiting green open space are high.Demand and supply of green space service are out of balance for both the northern and southern parts of the city.5) The frame of overall design for green open space system optimization is "1 center with 3 rings,4 belts with 3 axes,and 3 mountains with 4 wedges".The four levels of optimizing distribution pattern are "green rings revolving,green corridors interweaving,green dots interspersing and green background extending".Residence location and green space distribution need to be modified to find the balance in demand and supply of green space.Concrete measures should be taken to optimize the distribution and functionality of public open green system.