基于投资组合模型的海岸带土地利用效率研究—以上海临港新城围垦区为例

土地利用效率的评价对于土地管理者和决策者有着重要意义。论文以上海临港新城围垦区为例,通过构建土地利用投资组合模型,利用Sharpe 指数(θ)和单位风险的经济收益(δ)两个指标,评价了2003—2010 年临港土地利用的效果及土地管理的效率。研究结果显示,2003—2010 年,θ由0.11 提高到12.77,δ由0.69 提高到12.96,表明临港土地开发利用的效果明显。依据土地利用的效率边界分析发现,2003—2010 年,临港新城围垦区的Sharpe 指数(θ)和单位风险的经济收益(δ)均未达到最优值,其中2003 年表现为土地利用不足,2008 年土地利用状态介于“经济收益-风险”最优与“总收益-风险”最优之间,2010 年表现为土地利用强度过高。有关未来土地利用最优组合的估计,尚需更多数据和深入研究。

Coastal Land Use Efficiency Based on the Portfolio Model: A Case of Reclaimed Area of Lingang New City,Shanghai

It is very important to evaluate land use efficiency for land managers and policy makers. In this paper, through the portfolio model of land use, we evaluate the effect and efficiency of land use and management in reclaimed area of Lingang New City, Shanghai from 2003 to 2010, using two indicators of Sharpe index (θ) and economic return per unit of risk (δ). The result of the study shows that from 2003 to 2010, Sharpe index (θ) increased from 0.11 to 12.77 and economic return per unit of risk (δ) increased from 0.69 to 12.96, indicating that land use of reclaimed area of Lingang New City has a good effect. Analysis on the efficiency frontiers indicates that Sharpe index (θ) and economic return per unit of risk (δ) failed to achieve the optimal value from 2003 to 2010. The land use was under-utilization in 2003; the status of the land use in 2008 was between the optimal value of "economic return-risk" and the optimal value of "total return-risk" ; the intensity of land use in 2010 was too high. Because of the lack of data, it is difficult to estimate the optimal portfolio of the land use in the future.