云南测震台网地震监测能力分析

2018年1月云南省测震台网示范工程20个新增测震台建设完成,选取原有48个台以及新增20个台连续48小时数据记录,基于近震震级公式,计算并网前后云南省测震台网的地震监测能力,对比测震台增加前后的地震监测能力,发现:云南省地震监测能力由ML 2.2提升到ML 1.6,局部地区由ML1.4提升到ML0.8。     

Submersion simulation in a typical debris flow watershed of Jianzhuangchuan catchment,Loess Plateau

Debris flow is one of the most serious and frequent geological disasters that occur in the Loess Plateau. The outbreak of a debris flow is sudden, ferocious, swift, and destructive. The characteristics and mechanism of debris flow were explored in this study via survey, numerical simulation, and simulation analysis in a Loess Plateau area (Huangling County, Shaanxi Province, China). Numerical models and formulas corresponding to the occurrence and movement mechanism were established based on the HEC-RAS, HEC-GeoRAS, and SWAT results. The range of debris flow deposition was determined through capturing the debris flow free surface. A hydrological model and critical rainfall threshold were determined in order to provide technical support for debris flow forecasting in the Loess Plateau. The results suggest that 10-year floods do not submerge any portion of the basin. One village area was affected by the 100-year flood (total area of 0.648 km²) while four villages areas were submerged by the 1000-year flood (total area of 1.39 km²). The method presented here may provide a reliable scientific basis for mitigating loss due to debris flow hazards.     

边坡虹吸排水管内空气积累原因及应对措施

坡体地下水位上升是诱发滑坡的重要因素,实时排出地下水是防治边坡地质灾害的有效手段。虹吸排水具有免动力和流动过程由液位变化自动控制的物理特性,可满足实时排出坡体地下水的需要,但虹吸管中空气积累会导致虹吸过程中断,制约了边坡虹吸排水技术的推广应用。溶解于水的空气因虹吸管内压力降低而释出是形成气泡的物理基础。实验结果表明,虹吸进水口水面以上垂直高度3.5 m以上就会出现大量气泡,经过虹吸顶点后,气泡发生强烈的兼并形成大气泡。当虹吸管的进出水口的水头差较大时,气泡间的水弹容易推动气泡从出水口排出。当虹吸管直径大于5 mm时,缓慢的虹吸流动,会发生管内气泡的积累,最终破坏虹吸过程;虹吸管的直径小于4 mm时,可以形成基本稳定的弹状流。因此,为保持边坡虹吸过程长期有效,经常性降雨并且坡体地下水丰富的地区可选用直径为5 mm的虹吸管,非经常性降雨的地区应选择小于等于4 mm的虹吸管。     

地质聚合物技术的发展近况

概要介绍了一种无机聚合物———地质聚合物。首先对地质聚合物材料的制备过程作了介绍。根据原料的不同,地质聚合物材料的制备可以有两种途径:一种是以偏高岭石为基础原料,一种是以粉煤灰为主要原料。通常以硅酸钠水溶液作为单体硅源,氢氧化钠溶液作为碱激发剂以提高原料的溶出性。对某些在常温和低于100 ℃下制备的独石材料作了介绍。对煅烧高岭石,叶蜡石,粉煤灰和钢渣的溶出特性作了阐述。应用SEM EDX,对以粉煤灰为原料的地质聚合物材料的化学组成作了分析。最后对地质聚合物材料的经济性以及在环境保护等领域的应用前景,特别是在减少二氧化碳排放与废弃物处理方面的意义作了介绍。     

综合景观格局与经济指标进行土地利用二维尺度分区——以青海省为例

运用空间统计分析方法综合表征土地利用特征的景观格局指数和社会经济指数进行土地利用分区.经过指数降维、筛选指数因子进行系统聚类,在聚类分区方法的选择上,经过反复验证选定标准欧氏距离-加权平均法和明科夫斯基-加权平均法两种最佳匹配算法.将聚类结果合并分区,将青海省土地划分为4个区,各区地类景观和经济水平相异,分析结果对指导青海省土地利用合理规划开发意义重大.     

基于生态足迹的宁夏回族自治区可持续发展评价

对可持续发展能力的定量评估是进行可持续发展研究的关键,基于生态足迹计算的发展能力指标是较好的评价指标之一。采用生态足迹模型,首次对宁夏1991-2010年长时间序列生态足迹进行了计算,对生态赤字的构成进行了分析;修正了Ulanowicz的发展能力模型,创新性的在计算公式中将万元GDP生态赤字（盈余）因子引入,对宁夏生态经济系统的可持续发展能力进行了评价。结果表明：1991-2010年宁夏人均生态赤字高于全球0.4 hm2,和全国0.68 hm2的水平相比,1991-2010年宁夏生态赤字扩大5倍,20 a间系统稳定性逐渐下降,但近年有向良性化方向好转的趋势。在2010年资源利用效率最高;生态经济系统可持续发展能力持续上升,2010年最大,为2.993,是20 a前的16倍多。提高生态足迹多样性、提高资源利用效益,是宁夏提高发展能力的途径;且通过政策手段对能耗进行控制,宁夏建设可持续发展经济是可期待的。     

Dynamic programming approach for segmentation of multivariate time series

In this paper, dynamic programming (DP) algorithm is applied to automatically segment multivariate time series. The definition and recursive formulation of segment errors of univariate time series are extended to multivariate time series, so that DP algorithm is computationally viable for multivariate time series. The order of autoregression and segmentation are simultaneously determined by Schwarz’s Bayesian information criterion. The segmentation procedure is evaluated with artificially synthesized and hydrometeorological multivariate time series. Synthetic multivariate time series are generated by threshold autoregressive model, and in real-world multivariate time series experiment we propose that besides the regression by constant, autoregression should be taken into account. The experimental studies show that the proposed algorithm performs well.     

沧州地区地面沉降现状Sentinel-1A/B时序InSAR监测与分析

获取了22景IW模式的Sentinel-1A/B数据,分别采用PS-InSAR和SBAS-InSAR两种时序技术得到了沧州地区2015年11月至2016年11月期间地表平均沉降速率及累计沉降量。经分析,两种时序监测结果具有较高的一致性,其结果表明：献县、沧县、沧州市区地面表现为回升趋势;青县、沧县东部、南皮县西部、东光县等地区地面沉降量较大,其中东光县何庄村累计下沉量达47 mm,而引起这些区域地面沉降的主要原因为农业生产等带来的地下水开采。本文对基于Sentinel-1A/B SAR数据的时序分析方法在城市沉降监测方面的应用进行了探讨,为有关部门提供了重要的参考数据。     

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Dynamic programming-based optimization for segmentation and clustering of hydrometeorological time series

In this study, we propose a new segmentation algorithm to partition univariate and multivariate time series, where fuzzy clustering is realized for the segments formed in this way. The clustering algorithm involves a new objective function, which incorporates an extra variable related to segmentation, while dynamic time warping (DTW) is applied to determine distances between non-equal-length series. As optimizing the introduced objective function is a challenging task, we put forward an effective approach using dynamic programming (DP) algorithm. When calculating the DTW distance, a DP-based method is developed to reduce the computational complexity. In a series of experiments, both synthetic and real-world time series are used to evaluate the performance of the proposed algorithm. The results demonstrate higher effectiveness and advantages of the constructed algorithm when compared with the existing segmentation approaches.