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基于ANN-CA模型的黄土丘陵区县域土壤侵蚀演变预测

Prediction of soil erosion evolution in counties in the loess hilly region based on ANN-CA model

  • 摘要: 为了精准预测土壤侵蚀变化,科学合理地预防区域水土流失的发生,选择黄土丘陵沟壑区的彭阳县为研究区,2000、2008和2015年3期遥感影像、DEM和日降雨等为基础数据,基于GIS和RUSLE模型计算土壤侵蚀并定量分析2000-2015年时空分布变化特征;应用人工神经网络耦合元胞自动机构建ANN-CA模型,预测彭阳县2025年土壤侵蚀。结果显示:1)彭阳县2000-2015年土壤侵蚀状况整体呈现向好趋势;强度及强度以上侵蚀面积减少652.81 km2,高等级侵蚀逐渐向低等级转移;2)2015年土壤侵蚀强度模拟结果精度排序为:微度>轻度>中度>极强度>剧烈>强度,总体精度为87.9%,Kappa系数0.82,预测精度较高;3)彭阳县2025年土壤侵蚀以微度与轻度为主,面积分别为1 366.67和748.61 km2,占总面积的84.69%,强度以上面积仅为2.69 km2,占总面积的1.1%,较2015年进一步好转;强度以上侵蚀主要发生在孟塬乡与新集乡,可在该区域加强水土保持措施建设,预防水土流失。研究结果表明,ANN-CA模型具有较强的自学习与空间动态模拟能力,可以应用于区域土壤侵蚀预测。

     

    Abstract:
    Background With destroying the ecological environment and affecting the regional environmental carrying capacity, soil erosion has become one of the important issues restricting the sustainable development of society. Pengyang county is located in the second sub-region of the Loess Hilly and Gully Region, and is a key control area for soil erosion in the country. After years of vigorous management, the ecological environment has been effectively improved. In order to consolidate the management results, accurate soil erosion prediction results are the scientific basis for reasonable prevention of soil erosion.
    Methods Three phases of remote sensing images, DEM, and daily rainfall were used as basic datain 2000, 2008, and 2015, meanwhile soil erosion was calculated based on GIS and RUSLE models and the analysis area was quantified and characteristics of annual spatiotemporal distributionin 2000-2015. An ANN-CA model was constructed using an artificial neural network coupled with a cellular automaton and the six soil erosion factors R, K, C, P, L, and S were invoked as model input variables. The soil erosion intensity level was the initial state of the cell which made a prediction of soil erosion in Pengyang country in 2025.
    Results 1) Overall situation of soil erosion in Pengyang country from 2000 to 2015 indicated a positive trend. The area of erosion above the grade strong decreased by 652.81 km2 and high-grade erosion gradually shifted to low-grade. 2) The accuracy of soil erosion intensity simulation results in 2015 was ranked as follows: slight > light > medium > ultra strong > severe > strong, the overall accuracy was 7.9%, the Kappa coefficient was 0.82 and the prediction accuracy was high. 3) Soil erosion in Pengyang county in 2025 would be mainly slight and light with areas of 1 366.67 km2 and 7 486.61 km2, accounting for 84.69% of the total area. The area above the strong is only 2.69 km2, accounting for 1.1% of the total area which has improved further with compared with 2015. Erosion above the strong mainly occurred in Mengyuan and Xinjitown so that the construction of soil erosion conservation measures could be enhanced in this area to prevent soil erosion.Conculsions The research results illuminate that the ANN-CA model has significantly self-learning ability and spatial dynamic simulation function which are universal in regional soil erosion prediction.

     

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