基于信息量模型和频率比模型的江西省崩岗发育风险对比评估

    Assessing Benggang development risk in Jiangxi of China using information value and frequency ratio model

    • 摘要: 崩岗是中国南方红壤丘陵区最为严重的侵蚀形式之一,基于GIS开展江西省崩岗发育风险评估,对该地区崩岗侵蚀防治具有重要的科学意义。以江西省为研究区,应用灰色关联度分析法和皮尔逊相关性分析法,计算10个影响因子的重要性和相关性矩阵进行影响因子筛选,利用信息量、加权信息量和频率比3种模型开展江西省崩岗发育风险评估,采用自然断点分级法划分风险等级。结果表明:1)气温、海拔和土地利用类型是江西省崩岗发育的重要影响因子。2)信息量模型、加权信息量模型和频率比模型的受试者工作特征曲线下方面积(Area under curve,AUC值)分别为0.860、0.852和0.833,3种模型评估精度均良好,都适用于江西省崩岗发育风险评估。3)江西省崩岗发育风险等级分布具有显著的空间异质性,呈现由北往南逐渐递增的趋势,极高风险区主要集中分布在江西省南部,高风险区主要分布在江西省南部和中部,这与江西省崩岗实际分布情况基本一致。研究结果可为江西省崩岗侵蚀防治提供参考。

       

      Abstract: Benggang is one of the most serious failures in soil erosion, particularly in the red loam hilly areas in southern China. In this study, the risk assessment was carried out on Benggang development using GIS. A case study was taken from the granite area of Jiangxi Province, China. 17 049 sample points of Benggang were obtained using remote sensing interpretation and field survey. 10 potential influence factors of Benggang were also selected, such as the slope, aspect, elevation, topographic relief, rainfall erosion, temperature, lithological, soil type, land use type, and vegetation coverage. A systematic investigation was then implemented to explore the relationship among parameters and avalanche occurrence; Gray correlation and Pearson correlation analysis were applied to calculate the importance and correlation matrices of the influence factors. As such, the index system of Benggang risk assessment was obtained to screen the influence factors; Furthermore, quantitative analysis was also performed on the relationship among environmental impact factors and the development of Benggang; The weighted information and frequency ratio models were utilized to calculate the risk index of Benggang, according to the natural breakpoint grading. A series of tests were conducted to quantitatively evaluate the accuracy of the risk assessment. The best performance was selected to optimize the risk assessment model. The results show that: 1) The temperature, elevation and land use type were the main influencing factors on the development of Benggang in Jiangxi Province. Among them, 29 of the 67 graded indicators were used to promote the development of Benggang, while 38 indicators were to inhibit. 2) The number and percentage of Benggang in the zoning of the three models were positively correlated with the risk level. A higher percentage was found with the number of Benggang in the extreme and normal high-risk zones. Three models were selected to effectively assess the susceptibility of Benggang. The model accuracy was evaluated on the working characteristic curve of the subjects. The test results show that the AUC values of the information value model, the weighted information value model and the frequency ratio model were 0.860, 0.852 and 0.833, respectively, indicating the better assessment accuracy of three models. All of them were suitable for the assessment of the risk of Benggang. There was the slightly higher accuracy of the information value model. A more objective and accurate assessment was achieved on the risk of avalanche occurrence. 3) The risk level of Benggang shared a trend of gradual increase from the north to the south. The extreme high-risk area was concentrated mainly in the southern, while the high-risk area was distributed in the south and central. The finding can also provide a strong reference and data support to the prevention and control of Benggang erosion in Jiangxi Province.

       

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