中国4个城市范围CO2排放比较研究

基于点排放源和辅助数据,自下而上构建重庆1km CO2排放空间网格,分析市域(UB1)、市辖区(UB2)、建成区(UB3)和城区(UB4)4个城市范围的CO2排放特征.UB4是重庆城市合理表征,而UB1更适合于区域边界.城市边界选择的不同,将导致很大的排放差异.UB4的CO2总排放量仅为UB1的17.13%,但UB4的人均CO2排放量是UB1的1.6倍.UB4形成了重庆UB1的CO2排放核心,其内单位网格的平均排放量超过了10000t,而UB1内超过70%的范围内单位网格的排放水平都低于200t.工业排放占据绝对主体导致UB4人均排放水平较高,并且高于临近周边及区域人均水平,这和国际城市的情况正好相反.全局和局部显著空间正自相关性说明部分地区高强度的经济活动和能源活动对周边区域的排放有显著影响.基于网格的累积排放分析显示,个别网格的排放量已经占到UB4总排放的40%以上.UB4内7.00%的面积,UB1内1.21%的面积和UB2内3.84%的面积,其CO2排放都超过了其相应范围内总排放的85%.

CO2 emissions in four urban boundaries of China-Case study of Chongqing

Chongqing 1km resolution CO2 emission gridded data had been built up based on point emission sources and other supporting data. The CO2 emissions in Chongqing’s four urban boundaries, namely city administrative boundary (UB1), city district boundary (UB2), city built-up area (UB3) and urban proper (UB4), were analyzed and compared based on this emission gridded dataset. UB4 was the appropriate spatial boundary for city of Chongqing, while UB1 was suitable for the spatial boundary of Chongqing region. Different urban boundaries could result in substantial emission discrepancy. The total emissions of UB4 only accounted for 17.13% of the emissions of UB1, whereas the per capita emissions of UB4 were 1.6 times of UB1 level. The UB4, with average emissions of grid more than 10000tons, shaped the emissions center of the UB1. The emissions of grids in more than 70% area of UB1 were lower than 200tons. The predominant share of industrial emissions in total emissions in UB4 resulted in the spatial pattern that the per capita emissions were higher in urban area than in its peripheral area. This pattern was opposite to what was found in cities of developed countries. There was spatially clustering phenomenon in CO2 emissions in UB1, as indicated by spatial autocorrelation analysis. This implied that the economic activities and energy consumption in some areas have significant positive effect on its surroundings. Emissions of certain individual grid accounted for more than 40% of the total emissions in UB4. The emissions in 7.00% area of UB4, 1.21% area of UB1 and 3.84% area of UB2, had accounted for more that 85% of emissions in their correspondent urban boundaries.