基于ARIMA模型的辽河流域生态足迹动态模拟与预测

Dynamic simulation and prediction of ecological footprint in Liaohe River Basin based on ARIMA model

将能值与生态足迹理论相结合,引入能量折算系数,通过能值密度构建能值-生态足迹模型,并应用此模型对辽河流域2001—2010年生态承载力和生态足迹进行计算。生态承载力计算主要是自然生态承载力和本地产品产出承载力,其中自然生态承载力主要考虑可更新资源的承载力,本地产品产出承载力主要包括生物资源产出承载力和工业产品产出承载力。生态足迹的计算主要包括消费足迹和污染足迹,消费足迹主要测算生物资源消费、能源消费和水资源消费足迹。污染足迹主要测算废气和生活废水、工业废水对自然生态系统带来的负荷。测算结果表明:2001—2010年辽河流域人均生态承载力和人均生态足迹均有所增加,但是生态足迹的增长速度远远大于生态承载力,致使流域内自2001与2009年生态略有盈余外,其余年份均出现生态赤字,处于不可持续发展状态。以能值-生态足迹模型测算结果为基础,基于EViews采用自回归综合移动平均模型(ARIMA),对流域内10年的生态足迹和生态承载力进行动态模拟。首先通过ADF与PP单位根检验时间序列的平稳性;其次分析序列的自相关函数图和偏自相关函数,初步确定AR和MA的阶次;再根据R2、AIC及SC准则,进行模型参数估计并诊断分析;最后确定最佳模拟模型。以ARIMA模型预测2011—2015年辽河流域生态足迹和生态承载力的演变趋势。预测结果表明,人均生态足迹在未来5年内会继续呈直线式增长,到2015年达到7.387 8 hm2,是2001年的2.16倍;而人均生态承载力在2011年之后开始下降,生态赤字继续扩大,到2015年增长到-4.167 67,约为2005年的10倍,流域内不可持续发展形势会更加恶化。最后提出辽河流域生态安全建设的对策。能值-生态足迹模型测算结果与实地调研基本相符,较真实反映了辽河流域可持续发展状况。基于ARIMA模型模拟预测结果可为未来流域开发和建设提供参考依据。

In this work, Based on emergy analysis and the theory of ecological footprint, the emergy-ecological footprint model was established by the coefficient of energy conversion and emergy density. The ecological carrying capacity and ecological footprint in Liaohe River basin from 2001 to 2010 were calculated via this model. The calculation of ecological carrying capacity includes the carrying capacity of natural ecological and local products output. The carrying capacity of natural ecological mainly refers to the carrying capacity of renewable resources, and the carrying capacity of local product output mainly includes the carrying capacity of biological resources and industrial products output. The calculation of the ecological footprint includes consumption footprint and pollution footprint. The consumption footprint consists of the footprint of biological resources consumption, energy consumption and water consumption, and the pollution footprint mainly calculates the load of natural ecosystems brought by exhaust gas and waste water. The results showed that the growth speed of the per capita ecological footprint was greater than one of the ecological carrying capacity. So the ecological deficit occurred in retained years except for the slight ecological surplus in 2001 and 2009. Based on the results of the emergy-ecological footprint model, the autoregressive integrated moving average （ARIMA） model by EViews was introduced to stimulate the dynamic evolution trend in the research region during decade years. Firstly, the stationarity of time series was inspected by Dickey-Fuller （ADF） and Phillips-Perron （PP） unit root model. The diagram of the autocorrelation function and the partial autocorrelation function of the sequence were analyzed, and the order time of autoregressive （AR） and moving average （MA） were initially identified. Then the model parameters were diagnosed and estimated according to R-squared （R2）, Akanke＇s Information Criterion （AIC） and Schwarz Criterion （SC）. The best simulation model was determined. Secondly, the evolution trend of the ecological carrying capacity and ecological footprint in Liaohe River basin from 2011 to 2015 was predicted via the ARIMA model. The results show that the per capita ecological footprint will present a significant growth in the next five years. The per capita ecological footprint will be up to 7.3878 hm2 in 2015, and this value will be 2.16 times than that of 2001. While the per capital ecological carrying capacity may present a downward trend after 2011. The value will be up to -4.167 67 hm2 in 2015 and this will be about 10 times than that of 2005. Thus the situation of unsustainable development will become worse due to expanding ecological deficit. Finally, the eco-security countermeasures of Liaohe River basin were emphasized. The results of model calculation were basically consistent with the field research, and can truly reflect the situation of sustainable development in the Liaohe River basin. The results predicted by ARMIA model stimulation can provide a reference for future watershed development and construction.