基于InVEST模型的重庆市碳储量不确定性分析

Uncertainty Analysis of Carbon Storage in Chongqing Based on InVEST Model

城市化进程改变了土地利用格局,影响了陆地生态系统碳库中蕴含的碳储量,降低了生态系统的调节能力,直接关系到城市生态系统服务价值供给、土地利用规划。因此,理清城市发展过程中生态系统碳储量的时空变化及土地类型演变,对于探索城市可持续发展具有重要意义。然而目前相关研究中通常选用单一的土地利用/覆盖(LULC)数据集估算碳储量,导致研究结果具有较大不确定性。为此,该研究利用生态系统服务和权衡的综合评估模型(InVEST模型),结合多组常用LULC数据集,探索数据集选取对典型城市(重庆)碳储量估算、土地利用类型演变的影响,以期更好地反映城市发展过程中碳储量的时空变化及土地利用类型演变。结果表明:重庆市近10年的土地利用类型演变较为剧烈,大量耕地向建设用地、林地转移,2010-2020年间平均耕地转入建设用地的面积比2000-2010年多400 km^(2)以上;基于不同数据集估算的重庆市碳储量略有差异,估算结果在972.08~1069.70 TgC(10^(12)g C)之间;越靠近中心城区,碳储量下降越明显,主城区近20年的碳储量下降了(2.8±0.6)Tg C。研究结果说明在城市快速发展过程中,用地类型演变加速,更应注重生态环境保护和坚守用地红线,同时研究可为城市土地资源管理提供数据支撑,有利于制定更科学的土地资源管理规划。

The urbanization has been changing the pattern of land use,and at the same time has affected the amount of carbon stored in the carbon pools of terrestrial ecosystem so that the ecosystem’s regulating power has been declined,which is directly related to the supply of urban ecosystem service values,and the land use planning.Therefore,for the purpose of sustainable development in the process of urban development,it is of great significance to make clear the spatio-temporal changes of ecosystem carbon storage and the evolution of land use;however,in current relevant studies,a single land use/cov⁃er(LULC)dataset is usually used to estimate carbon stocks,so that the results of those studies come to be rather uncertain.Hence,in this study the integrated valuation model of ecosystem services and the trade-offs(InVEST)model are utilized,combining with the multiple commonly-used LULC datasets,to explore the impact of dataset selection on carbon stock esti⁃mation and land use type evolution in a typical city,e.g.,Chongqing City,in order to better reflect the spatial and temporal changes in carbon stocks and the type of land use evolution during the city’s urban development.As a result,the study pres⁃ents that the LULC change in Chongqing over the past 10 years is rather severe than before,and a large amount of cultivated land shifted to forest land or construction land,and compared with the years 2000-2010,during 2010-2020 the average area of cultivated land transferred to construction land is more than 400 km^(2);the carbon storage estimated by different datasets var⁃ies slightly,and the estimated storage was between 972.08~1069.70 Tg C(10^(12)g C),the closer the area to the main city zone,the more remarkable decline in carbon storage,and the carbon storage of the main city zone decreased by(2.8±0.6)Tg C during the past 20 years.In addition,the study reveals that in the process of rapid urban development,the evolution of land use pattern rather accelerated,so more attention should be paid to ecological environmental protection,strictly adhering to the red line of land use.Summarily,the achievement of the study could offer a data support for urban land resource management,be⁃ing conducive to formulating more scientific land resource management planning.