洪灾风险评价与区划研究进展

洪灾风险评价是洪灾风险管理的首要步骤。洪灾风险区划是在洪灾风险评价基础上的宏 观分区, 有助于更清晰的把握洪灾风险的空间格局与内在规律。文章首先对洪灾风险相关概念进 行了阐述, 试图达到理清和规范的目的。然后对洪灾风险评价常用方法和洪灾风险区划研究进行 了评述。目前主要的洪灾风险评价方法有地貌学方法、水文水力学模型与系统仿真模拟方法、基 于历史灾情数据的方法、基于水灾史料和古洪水调查的方法、遥感与GIS 方法、基于洪灾形成机 制的系统分析方法等。最后对洪灾风险评价与洪灾风险区划研究进行了小结, 并指出了未来在洪 灾风险评价与区划的数据基础、洪灾风险评价的时空尺度、洪灾风险区划的理论与方法、洪灾风 险评价与区划的技术手段等方面的可能发展前景。     

宁夏河东沙地不同坡度柠条锦鸡儿（Caragana korshinskii）水分利用策略差异

为探讨全球气候变化背景下多元线性混合模型（IsoSource）和贝叶斯混合模型（MixSIAR）解析宁夏河东沙地柠条锦鸡儿（Caragana korshinskii）水分利用策略差异及适用性,利用氢氧稳定同位素技术,结合直接对比法、IsoSource模型和MixSIAR模型对比分析不同坡度（6°、10°、16°和24°）样地柠条锦鸡儿在生长季不同时期对各潜在水源的利用率,并评估两种模型的植物水分溯源效果。结果表明：柠条锦鸡儿对不同土层深度土壤水的利用存在明显的季节性差异,生长季初期,随着坡度的增大,柠条锦鸡儿对中层土壤水的利用率呈现出先增大后减小的趋势;生长季中期,随坡度增大,柠条锦鸡儿主要水分来源由深层土壤转移至浅层土壤;生长季后期,柠条锦鸡儿主要水分来源随着坡度的增大由浅层土壤转移至深层土壤。基于直接对比法的定性判断结果,IsoSource模型和MixSIAR模型计算坡度6°、10°和16°样地柠条锦鸡儿主要水分来源利用率的适用性均较高;而Mix-SIAR模型计算坡度24°样地柠条锦鸡儿主要的水分来源以及其贡献率具有更高的可靠性。Iso-Source模型更适合解析较小坡度（6°和1...     

Interdecadal Change in the Interannual Variation of the Western Edge of theWestern North Pacific Subtropical High During Early Summer and the Influenceof Tropical Sea Surface Temperature

This study reveals that the interannual variability of the western edge of the western North Pacific(WNP)subtropical high(WNPSH) in early summer experienced an interdecadal decrease around 1990. Correspondingly, the zonal movement of the WNPSH and the zonal extension of the high-pressure anomaly over the WNP(WNPHA) in abnormal years possess smaller ranges after 1990. The different influences of the tropical SSTAs are important for this interdecadal change, which exhibit slow El Nino decaying pat...     

中国区域平均降水量序列构建方法比较研究

由于地面观测台站空间分布不均匀,运用不同区域平均技术方法研究中国降水特征和变化规律的结果存在显著差异,是区域降水变化研究不确定性的重要来源之一.本文以"中国地面与CMORPH(CPC Morphing Technique)融合逐日降水产品"作为参照值,基于中国地面2425站观测资料,采用5种网格尺寸的经纬度网格面积加权...     

基于红外探测器焦平面成像的白天测星技术研究

对于大气层以下的传统可见光天文导航,存在白天日照强烈而无法观测星体,数据缺乏连续性,可观测恒星数量少,无法实现全天时天文导航等问题。文中设计并探究利用红外探测器焦平面成像技术来取代可见光CCD成像技术的短波红外天文导航方法,分析短波红外波段相对于可见光波段,在大气层内白天观星实现全天时天文导航的优势,并对其可行性进行实验分析。实验结果表明,基于红外探测器的天文导航方法,在太阳辐射较弱的清晨或黄昏等时段,可以成功拍摄到可见光CCD仪器无法观测到的短波红外波段的恒星,对于实现全天时天文导航具有一定的参考意义。夜间短波红外波段的可供观测恒星数量远远多于可见光恒星数量,这对于增加多余观测量,保证连续测量输出,提高天文导航定位定向的精度,具有实际的应用价值。     

Mantle dynamics of the Paleoproterozoic North China Craton: A perspective based on seismic tomography

We investigate the mantle dynamics beneath the North China Craton (NCC) and surrounding regions based on a synthesis of recent P-wave mantle tomographic data down to depths of 600–800 km and their correlation with the surface geological features, with particular reference to the Paleoproterozoic tectonic events associated with the incorporation of the NCC within the Columbia supercontinent amalgam. From the tomographic images, we identify a hot corridor in the mantle transition zone beneath the central region of the Western Block of the NCC sandwiched between two cold corridors. This scenario is similar to the donut-shaped high-velocity anomaly surrounding a region of low-velocity anomaly in the lowermost mantle under the Pacific and suggests that the cold regions might represent slab graveyards which provide the fuel for the plumes rising from the center. A tomographic transect along the collisional suture of the NCC with the Columbia supercontinent, covering the Yinshan-Ordos Blocks in the Western Block through the Central Orogenic Belt and into the Eastern Block of the NCC reveals a ca. 250 km thick lithospheric keel below the Ordos Block defined by a prominent high-velocity anomaly. We identify slab break-off and asthenospheric upwelling in this region and suggest that this process probably initiated the thermal and material erosion of the tectosphere beneath the Eastern Block from the Paleoproterozoic, which was further intensified during the Mesozoic when a substantial part of the sub-continental mantle lithosphere was lost. We visualize heat input from asthenosphere and interaction between asthenosphere and overlying carbonated tectosphere releasing CO₂-rich fluids for the preservation of ultra-high temperature (ca. 1000 °C) metamorphic rocks enriched in CO₂ as well as high-pressure mafic granulites as a paired suite in this region. We also identify a hot swell of the asthenosphere rooted to more than 200 km depth and reaching up to the shallow mantle in the tomographic section along 35°N latitude at a depth of 800 km. This zone represents a cross-section through the southern part of the NCC. The surface distribution of Paleoproterozoic Xiong’er lavas and mafic dykes in this region would indicate that this region might have evidenced similar upwellings in the past. Our study has important implications in understanding the evolution of the NCC and suggests that the extensive modification of the mantle architecture and lithospheric structure beneath one of the fundamental Precambrian nuclei of Asia had a prolonged history probably dating from the Paleoproterozoic suturing of the NCC within the Columbia supercontinent amalgam.     

The Characteristics of Migration of Ore Solutions in No.6 East Tin Deposit of the Songshujiao Orefield, Gejiu

No. 6 East tin deposit in the Songshujiao orefield, Gejiu, is characterized by one-stage hydrothermal activity and monotonous country rocks. The authors selected this deposit and used the multivariate statistical analysis to study the types of association of main ore-forming elements at different temperatures and pressures and their distribution in the deposit. On that basis combined with the structural analysis of the deposit, the recto-geochemical features of No.6 East tin deposit have been revealed and the direction and channel of migration of the ore solutions in faults and the deposit have been deduced. This research can appropriately elucidate the control of faults on the migration of ore solutions and the sites where ore solutions are dispersed and accumulated, thus providing the theoretical basis for the prediction of hydrothermal deposits in question.     

基于GIS的单元簇遗传建模及其在区域矿产预测中的应用

论述一种GIS支持下的基于"单元簇”概念和遗传建模的多源地学信息综合分析方法及在多目标矿产预测中的应用.在以往矿产定量预测中,根据随机抽样思想进行单元划分,对空间信息利用不够充分.用单元的空间组合("单元簇”)代替单元作为定量类比的基本单位,从而能较好实现地质变量值及其所反映的局部地质空间结构的定量类比;将单元作为GIS区图元,利用GIS空间分析功能实现对单元及单元簇的管理和操作;以已知样品判对率最大为适应值计算准则,用遗传算法建立线性判别函数,可快速有效地实现多目标矿产定位预测.以新疆康古尔塔格地区金矿预测实例说明了其应用效果.     

试论非法占用湿地行为承担法律责任及湿地立法建议

介绍了非法占用湿地行为及湿地的概念,阐述我国立法保护湿地的现状,探讨非法占用湿地行为应承担法律责任的现状以及我国现行湿地管理法律体系存在的缺陷,呼吁尽快出台湿地保护专门法律,并提出湿地立法建议,旨在为我国保护湿地立法提供参考,同时也为林业执法、司法提供理论依据。     

NUMERICAL STUDY ON THE MIXING OF UNSORTED SEDIMENT PARTICLES DISCHARGED INTO A CROSS-FLOW BY MULTIPHASE PARTICLE-IN-CELL （MP-PIC） METHOD

The mixing characteristics of dredged sediments of variable size discharged into cross-flow are studied by an Eulerian-Lagrangian method. A three-dimensional (3D) numerical model has been developed by using the modified k-ε parameterization for the turbulence in fluid phase/water and a Lagrangian method for the solid phase/sediments. In the model the wake turbulence induced by sediments has been included as additional source and sink terms in the k-ε model; and the trajectories of the sediments are tracked by the Lagrangian method in which the sediment drift velocities in cross-flow are computed by a multiphase particle-in-cell (MP-PIC) method and the diffusion process is approximated by a random walk model. The hydrodynamic behavior of dumped sediment cloud is governed by the total buoyancy on the cloud, the drag force on each particle and velocity of cross-flow. The cross-flow destroys more or less the double vortices occurred in stagnant ambience and dominates the longitudinal movement of sediment cloud. The computed results suggest satisfactory agreement by comparison with the experimental results of laboratory.