1 Introduction介绍
土壤作为陆地生态系统碳库的重要组成部分，在调节碳氧化物浓度和减缓全球变暖方面发挥着重要作用。人类活动引起的土地利用/覆被变化（LUCC）是影响土壤有机碳库的关键因素之一。随着城市化进程的加快和城市化水平的提高，邻近的土壤经历了快速变化。因此，对城市土地利用系统的SOC、空间分布及其与LUCC的时间变化进行评估，可以为政府制定有效的减排措施和增加碳汇提供科学依据。此外，它有助于全球SOC循环研究的研究和全球变化的预测未来。
上海是中国经济最发达的城市。近年来，随着经济的快速发展，工业化、城镇化快速发展已经成为上海最重要的土地利用格局的变化在中国的地区，对城市土壤碳库的巨大影响。此外，上海地处东部沿海地区，使其成为未来影响全球气候变化最为严重的地区。
As an important component of terrestrial ecosystem carbon Pool, soils play a significant role in regulating the concentration of carbon oxide (CO2) and mitigating global warming. Land use and cover change (LUCC) caused by the human activities becomes one of the key factors affecting the soil organic carbon (SOC) pool. With the development of urbanization and increasing urbanized area, soils adjacent to cites experience rapid change. Therefore an assessment of SOC in urban area, their spatial distribution and temporal variation associated with LUCC, can provide scientific basis for government to make effective measures to reduce carbon emission and increase carbon sink. In addition, it can contribute to the research of global SOC cycling research and the prediction of global change in the future.
Shanghai is one of China's most economically developed cities. In recent years, with the rapid development of economy, rapid industrialization and urbanization have made Shanghai become the area with the most significant land use pattern changes in China, making great impacts on the urban soil carbon pool. In addition, Shanghai locates in the eastern coastal region, which makes it become the area most greatly affected the global climate change in the future.
1.2 Definition of Soil Carbon Sequestration (SCS)
What is Soil Carbon Sequestration (SCS)? The so-called carbon dioxide from the atmosphere into the soil through crop residues and other organic solids, and in a form that is not immediately reemitted.
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Figure 1-1 The sources and sink of carbon and its interplay in pedosphere, atmosphere and hydrosphere. The carbon stocks in various pools (including fossil fuels) were obtained from Batjes (1996), Lal (2004a, b,2008), and the carbon efflux (including fossil fuel burning) data were from IPCC (2000, 2007).
1.3 Soil Carbon Sequestration and Land-Use Change
Various land-uses result in very rapid declines in soil organic matter (Jenny 1941, Davidson and Ackerman 1993, Mann 1986, Schlesinger 1985, Post and Mann 1990). Much of this loss in soil organic carbon can be attributed to reduced inputs of organic matter, increased decomposability of crop residues, and tillage effects that decrease the amount of physical protection to decomposition. When agricultural land is no longer used for cultivation and allowed to revert to natural vegetation or replanted to perennial vegetation, soil organic carbon can accumulate by processes that essentially reverse some of the effects responsible for soil organic carbon losses from when the land was converted from perennial vegetation (Post and Kwon, 2000, pp.317) .
2 Research questions
On the basis of combined methods involving geographical information system (GIS), remote sensing (RS) and soil carbon analyze, the objectives of this studies are: 1) the land use and cover change of Shanghai during 1990-2010; 2) estimates of soil carbon pools in different periods Shanghai; 3) Dynamic changes caused by land use change in soil carbon pool.
3. The study area
3.1 Location and area of Shanghai
Shanghai (N31°14’, E121°29’) locates in the Yangtze River delta, adjacent to the East China Sea, Hangzhou Bay, Zhejiang and Jiangshu province (Figure 3-1).
4. The research contents and methodology
5. Temporal and spatial variations of land use in Shanghai
5.1 Research significance of regional land use for the carbon cycle
Land is the basic natural and material resources for the survival and development of humanity. Land use/land cover change is increasingly being recognized as a critical and urg
