不同空间尺度的山洪灾害风险评价模型对比研究

以山洪灾害风险评价的多准则决策模型、最大熵模型、信息量模型三种常见模型为研究对象,选取河西走廊和张掖市为地理区划（大中）、市域（小）空间尺度研究区,构建山洪灾害风险评价指标体系,分别完成基于三种模型的两种空间尺度的山洪灾害风险评价制图,基于甘肃省地质灾害调查与区划报告数据从模型验证、空间自相关、精度对比和尺度效应等角度对比分析三个模型应用于不同空间尺度的适应性,并给出优选模型。结果表明：最大熵模型是河西走廊（地理区划）空间尺度上山洪灾害风险评价的优选模型;多准则决策模型不适用于张掖市（市域）空间尺度评价,且三个模型运行结果均没有河西走廊（地理区划）空间尺度上表现良好;三个模型的尺度效应明显,在地理区划空间尺度上应用较良好,缩小至市域空间尺度上模拟结果误差增大;不同空间尺度上,最大熵模型均优于多准则决策模型和信息量模型,适用于地理区划（大中）、市域（小）空间尺度的山洪灾害风险评价。     

中国SLR在南半球观测取得良好进展

本文简要介绍了用中国研制的人造卫星激光测距仪(SLR),安装在阿根廷与San Juan大学天文台开展SLR合作观测与研究的意义,以及这个SLR系统的指标和性能.该仪器系统于2006年初在阿根廷国立San Juan大学天文台工作以来,进展良好,取得了观测数量丰富、精度高的优良结果.该合作的进展状况和未来的发展设想也在文中做了介绍.     

三维地质模型在泰安市地下空间开发中的应用

在城市化进程不断加快的今天,城市地下空间开发利用已经成为提高城市容量、缓解交通、改善环境的重要手段。为全面深化对泰安城市地下空间的认识,有效挖掘城市后备空间资源的巨大潜力,通过综合集成钻孔编录、地质图件和数字地形图等多源地学数据,借助MapGIS三维地质建模软件,初步建立起泰安城市三维地质模型,以直观的方式表达工程岩土体空间分布等地质信息,为更好地保护利用泰安市地下空间提供地质依据。     

THE APPLICATION OF IMAGE-BASED MODELING IN PALEOEARTHQUAKE TRENCH STUDY

The geological structure exposed by paleoearthquake trenches is the key material to the right cognition of fault activity and paleoearthquake. However, paleoearthquake trenching inevitably destroys active tectonic geomorphic evidence and trench exposures are usually difficult to reserve. The conventional process of recording the delicate geological information, manually constructing photomosaics by image-editing software, is time-consuming and produces undesirable artificial distortions. Herein, we explored the process of constructing trench orthophotomosaics and the 3D image model using the Image-based Modeling technology and applied it to the Liutiaohe trench across the Tianqiaogou-Huangyangchuan Fault, Gansu Province. Based on the 3D image modeling and orthophotomosaic, we firstly constructed the control points and scale bars on cleaned trench walls and collected photos of all sections of the trench with a digital camera in the field, and then reconstructed the 3D model of the trench through the Agisoft PhotoScan, an efficient image-based modeling software, and finally yielded the 3D image model of the trench and othophotomasaics of the trench exposures. The results show that the automated workflow can produce seamless, sub-millimeter-level high-resolution photomosaics more quickly, with precision in the centimeter range, and the 3D image model is of great help to identify strata and geological structures in trenches with much lower capital and labor costs and low expertise levels compared with LiDAR, meanwhile, the 3D archive benefits the share and communication and even allows future reinterpreting the site using new insights.     

Temporal variations in aerosol composition at Lanzhou City,Northwestern China

Although Lanzhou is one of the most heavily polluted cities in China, the composition of its air pollutants have not yet been studied in detail. The data of four months on the concentrations and compositions of ions from daily air-filter samples in the winter and spring during 2007–2008 were analyzed to investigate temporal trends and their possible causes. The results indicate that mean concentrations of almost all the aerosol components are greater in winter than in spring due to stronger emissions in winter and weaker localized dispersion. Spring dust storms are the major cause of the highest peak PM10 concentrations recorded during the study period; however, these elevated levels were transient. Ion concentrations related to coal combustion show the greatest reduction from winter to spring, while the concentrations of strong crustal components show a less-pronounced reduction. Strong cycles in the levels of particulate matter (PM) and all ions are also observed during the winter months due to meteorological conditions. Depending on the season, nine different ions accounted for 20%–50% of the PM concentration. The particle size of polluting ions was constant at times of increasing PM concentrations (particularly during winter), whereas the particle size of crustal ions increased dramatically during spring dust storms. Local meteorological conditions (especially wind speed) have a strong influence on the levels of pollutants. Four dust storms were noted, including one during winter. In summary, the regional transport of desert dust from the Gobi can significantly affect air quality and the chemical composition of aerosols in Lanzhou. The dust storms can strongly increase concentration of crustal ions, which are characteristics of deserts in northwestern China. This observation is in agreement with back-trajectories, which show reduced levels of pollutant ions during dust storms. Data on nitrate:sulfate ratios indicate that stationary point sources are the main source of ions rather than mobile sources.     

FY2海面温度产品质量检验方法与误差分析

主要介绍了风云二号静止气象卫星海面温度产品的质量检验方法及检验流程,给出了FY2E业务海面温度产品和FY2F海面温度算法的质量检验结果,并从误差统计、反演算法、系统设计等方面分析了目前FY2海面温度产品与国外卫星海面温度产品差异大的原因。现场海面温度质量检验和分析场海面温度交叉检验各有优缺点。现场海面温度质量检验能够对FY2 SST产品给于客观的评价。国外分析场海面温度具有时效性好、全球覆盖且质量均一的优点,分析场海面温度交叉检验能满足FY2 SST质量检验的时效性,是对FY2 SST的相对检验。通过静止卫星海面温度产品质量检验信息可以为产品研发人员和相关用户提供参考。     

Lateral extrusion along the Altyn Tagh Fault,Qilian Shan (NE Tibet): insight from a 3D crustal budget

The lithospheric strike‐slip Altyn Tagh Fault has accommodated hundreds of kilometres of displacement between the Qaidam and Tarim blocks since its Eocene reactivation. However, the way the deformation is accommodated in the Qilian Shan and further east remains uncertain. Based on 360 km of north‐eastward migration of the relatively rigid Qaidam block along the Altyn Tagh Fault and 3D isovolumetric balancing of the crustal deformation within the Altyn Tagh Fault–Qilian Shan system, we demonstrate that 250 ± 28 km (43.8–49.4%) of N20E directed crustal shortening and an additional ~250–370 km of eastward motion of the Qilian Shan crust must be accounted for by strike‐slip faulting in the Qilian Shan and crustal thickening in the Qinling area, as well as by extension in the adjoining North China block graben systems.     

Soil moisture potential and water content in the unsaturated zone within the arid Ejina Oasis in Northwest China

Three soil profiles were selected in the Ejina Oasis, northwest China, to determine water content profiles and evolution of soil moisture potentials in the unsaturated zone within the arid area. The total soil moisture potentials have been monitored for about 3 months in 2001 at different depths in the soil profiles. The occurrence and movement of water in the unsaturated zone was analyzed using the zero flux plane (ZFP) method. It is shown that convergent ZFPs and divergent ZFPs may occur at depths between 0.5 and 3.0 m, and that the depth of the ZFPs was controlled by the root zone of plants growing on the land surface. Profiles of the total soil moisture potentials were observed to be coincident with those of the water contents at the three experimental sites. The total soil moisture potential showed a slight increasing trend and the ZFPs tend to vanish from summer to winter as the water extraction by roots decreased. Evapotranspiration through vegetation has an important bearing on the water content and the total potential in the unsaturated zone.     

Characteristics, Formation Periods, and Controlling Factors of Tectonic Fractures in Carbonate Geothermal Reservoirs: A Case Study of the Jixianian System in the Xiong’an New Area, China

As typical carbonate geothermal reservoirs with low porosity in northern China, the Jixianian System in the Xiong’an New Area is the main target for geothermal fluid exploration. The Jixianian System comprises the Gaoyuzhuang, Yangzhuang, Wumishan, Hongshuizhuang, and Tieling formations. The characteristics, formation periods, and controlling factors of reservoir tectonic fractures have been determined based on analyses of outcrops, cores, thin sections, and image logs. The results show that unfilled fractures account for over 87% and most tectonic fractures are high-angle shear fractures with angles concentrated at 40° to 70° and the fracture porosity increases linearly with an increased fracture aperture. Within the same tectonic setting and stress field, the lithology and layer thickness are the dominant factors governing the development of tectonic fractures, which are the most developed in dolomites and thin layers. Tectonic fractures were most likely formed in regions near faults or areas with larger stress gradients. The tectonic fractures in the carbonate geothermal reservoirs are roughly divided into four sets: NNW–SSE and NNE–SSW oriented ‘X’-conjugated shear fractures formed from the Paleozoic to the pre-Yanshanian Movement; NE–SW-oriented shear fractures, formed in episode B of the Yanshanian Movement, occurred at the Early Cretaceous; nearly E–W-oriented tensional fractures formed in the late Yanshanian Movement at the Late Cretaceous to Paleogene, and NEE–SW-oriented shear fractures formed during the Himalayan movement.