Land subsidence is a major factor that affects metro line （ML） stability. In this study, an improved multi- temporal interferometric synthetic aperture radar （InSAR） （MTI） method to detect land subsidence near M...Land subsidence is a major factor that affects metro line （ML） stability. In this study, an improved multi- temporal interferometric synthetic aperture radar （InSAR） （MTI） method to detect land subsidence near MLs is presented. In particular, our multi-temporal InSAR method provides surface subsidence measurements with high observation density. The MTI method tracks both point-like targets and distributed targets with temporal radar back- scattering steadiness. First, subsidence rates at the point targets with low-amplitude dispersion index （ADI） values are extracted by applying a least-squared estimator on an optimized freely connected network. Second, to reduce error propagation, the pixels with high-ADI values are classified into several groups according to ADI intervals and processed using a Pearson correlation coefficient and hierarchical analysis strategy to obtain the distributed targets. Then, nonlinear subsidence components at all point-like and distributed targets are estimated using phase unwrapping and spatiotemporal filtering on the phase residuals. The proposed MTI method was applied to detect land subsidence near MLs of No. 1 and 3 in the Baoshan district of Shanghai using 18 TerraSAR-X images acquired between April 21, 2008 and October 30, 2010. The results show that the mean subsidence rates of the stations distributed along the two MLs are -12.9 and -14.0 ram/year. Furthermore, three subsidence funnels near the MLs are discovered through the hierarchical analysis. The testing results demonstrate the satisfactory capacity of the proposed MTI method in providing detailed subsidence information near MLs.展开更多
为解决黑河中游大满灌区水资源分配不合理,地下水超采等问题,该研究根据灌区实际情况预测了不同规划年(2026、2030年)灌区的需水量,提出了一种包含成本效益、缺水风险和磷污染控制的多目标水资源配置模型,采用自适应的非支配排序遗传算...为解决黑河中游大满灌区水资源分配不合理,地下水超采等问题,该研究根据灌区实际情况预测了不同规划年(2026、2030年)灌区的需水量,提出了一种包含成本效益、缺水风险和磷污染控制的多目标水资源配置模型,采用自适应的非支配排序遗传算法(adaptive nondominated sorting genetic algorithmⅢ,A-NSGA-Ⅲ)对模型进行求解,建立水资源配置方案评价体系,通过客观赋权法(criteria importance through intercriteria correlation,CRITIC)-优劣解距离法(technique for order preference by similarity to an ideal solution,TOPSIS)法对不同配置方案进行优选。结果表明:大满灌区2026年和2030年规划的供水量指标较预测的最大需水量分别缺水约1383.97万和332.93万m^(3),水资源供需矛盾突出;经优化配置后,2026年和2030年灌区用水总量分别是21043万和21459.17万m^(3),均满足灌区规划年供水总量指标约束;相较2021年,配置方案中不同规划年地表水使用量分别增加约3171.95万和4943.59万m^(3),地下水开采量减少约6301.48万和7656.95万m^(3),较大程度地减少了灌区地下水的开采量。该研究提出的多目标水资源优化配置模型在大满灌区有较好的适用性,水资源优化配置方案符合实际,可为黑河中游其他灌区的水资源优化配置提供理论支撑和参考依据。展开更多
文摘Land subsidence is a major factor that affects metro line （ML） stability. In this study, an improved multi- temporal interferometric synthetic aperture radar （InSAR） （MTI） method to detect land subsidence near MLs is presented. In particular, our multi-temporal InSAR method provides surface subsidence measurements with high observation density. The MTI method tracks both point-like targets and distributed targets with temporal radar back- scattering steadiness. First, subsidence rates at the point targets with low-amplitude dispersion index （ADI） values are extracted by applying a least-squared estimator on an optimized freely connected network. Second, to reduce error propagation, the pixels with high-ADI values are classified into several groups according to ADI intervals and processed using a Pearson correlation coefficient and hierarchical analysis strategy to obtain the distributed targets. Then, nonlinear subsidence components at all point-like and distributed targets are estimated using phase unwrapping and spatiotemporal filtering on the phase residuals. The proposed MTI method was applied to detect land subsidence near MLs of No. 1 and 3 in the Baoshan district of Shanghai using 18 TerraSAR-X images acquired between April 21, 2008 and October 30, 2010. The results show that the mean subsidence rates of the stations distributed along the two MLs are -12.9 and -14.0 ram/year. Furthermore, three subsidence funnels near the MLs are discovered through the hierarchical analysis. The testing results demonstrate the satisfactory capacity of the proposed MTI method in providing detailed subsidence information near MLs.
文摘为解决黑河中游大满灌区水资源分配不合理,地下水超采等问题,该研究根据灌区实际情况预测了不同规划年(2026、2030年)灌区的需水量,提出了一种包含成本效益、缺水风险和磷污染控制的多目标水资源配置模型,采用自适应的非支配排序遗传算法(adaptive nondominated sorting genetic algorithmⅢ,A-NSGA-Ⅲ)对模型进行求解,建立水资源配置方案评价体系,通过客观赋权法(criteria importance through intercriteria correlation,CRITIC)-优劣解距离法(technique for order preference by similarity to an ideal solution,TOPSIS)法对不同配置方案进行优选。结果表明:大满灌区2026年和2030年规划的供水量指标较预测的最大需水量分别缺水约1383.97万和332.93万m^(3),水资源供需矛盾突出;经优化配置后,2026年和2030年灌区用水总量分别是21043万和21459.17万m^(3),均满足灌区规划年供水总量指标约束;相较2021年,配置方案中不同规划年地表水使用量分别增加约3171.95万和4943.59万m^(3),地下水开采量减少约6301.48万和7656.95万m^(3),较大程度地减少了灌区地下水的开采量。该研究提出的多目标水资源优化配置模型在大满灌区有较好的适用性,水资源优化配置方案符合实际,可为黑河中游其他灌区的水资源优化配置提供理论支撑和参考依据。
