2003年9月19日陕西暴雨分析

利用太原地区发生的798个地质灾害个例和汛期降水资料,从地质环境背景着手,在地理信息系统(MAPGIS)支持下,对太原地质灾害危险性区划和诱发因素进行了系统研究。提出了精细的地质环境概率量化评价方法,得出了地质灾害影响因素的重要结论。建立了地质灾害预报模型,制定了预报等级标准和预报规则。经业务试验,预报结果与实况基本吻合。     

Stochastic Modelling of the Impact of Flood Protection Measures Along the River Waal in the Netherlands

River flooding is a problem of international interest. In the past few years many countries suffered from severe floods. A large part of the Netherlands is below sea level and river levels. The Dutch flood defences along the river Rhine are designed for water levels with a probability of exceedance of 1/1250 per year. These water levels are computed with a hydrodynamic model using a deterministic bed level and a deterministic design discharge. Traditionally, the safety against flooding in the Netherlands is obtained by building and reinforcing dikes. Recently, a new policy was proposed to cope with increasing design discharges in the Rhine and Meuse rivers. This policy is known as the Room for the River (RfR) policy, in which a reduction of flood levels is achieved by measures creating space for the river, such as dike replacement, side channels and floodplain lowering. As compared with dike reinforcement, these measures may have a stronger impact on flow and sediment transport fields, probably leading to stronger morphological effects. As a result of the latter the flood conveyance capacity may decrease over time. An a priori judgement of safety against flooding on the basis of an increased conveyance capacity of the river can be quite misleading. Therefore, the determination of design water levels using a fixed-bed hydrodynamic model may not be justified and the use of a mobile-bed approach may be more appropriate. This problem is addressed in this paper, using a case study of the river Waal (one of the Rhine branches in the Netherlands). The morphological response of the river Waal to a flood protection measure (floodplain lowering in combination with summer levee removal) is analysed. The effect of this measure is subject to various sources of uncertainty. Monte Carlo simulations are applied to calculate the impact of uncertainties in the river discharge on the bed levels. The impact of the “uncertain” morphological response on design flood level predictions is analysed for three phenomena, viz. the impact of the spatial morphological variation over years, the impact of the seasonal morphological variation and the impact of the morphological variability around bifurcation points. The impact of seasonal morphological variations turns out to be negligible, but the other two phenomena appear to have each an appreciable impact (order of magnitude 0.05–0.1 m) on the computed design water levels. We have to note however, that other sources of uncertainty (e.g. uncertainty in hydraulic roughness predictor), which may be of influence, are not taken into consideration. In fact, the present investigation is limited to the sensitivity of the design water levels to uncertainties in the predicted bed level.     

The 17 March 2005 Kuzulu landslide (Sivas, Turkey) and landslide-susceptibility map of its near vicinity

Landslides are common natural hazards in the seismically active North Anatolian Fault Zone of Turkey. Although seismic activity, heavy rainfall, channel incisions, and anthropogenic effects are commonly the main triggers of landslides, on March 17, 2005, a catastrophic large landslide in Sivas, northeastern of Turkey, the Kuzulu landslide, was triggered by snowmelt without any other precursor. The initial failure of the Kuzulu landslide was rotational. Following the rotational failure, the earth material in the zone of accumulation exhibited an extremely rapid flow caused by steep gradient and high water content. The Agnus Creek valley, where Kuzulu village is located, was filled by the earth-flow material and a landslide dam was formed on the upper part of Agnus Creek. The distance from the toe of the rotational failure down to the toe of the earth flow measured more than 1800 m, with about 12.5 million m³ of displaced earth material. The velocity of the Kuzulu landslide was extremely fast, approximately 6 m/s. The main purposes of this study are to describe the mechanism and the factors conditioning the Kuzulu landslide, to present its environmental impacts, and to produce landslide-susceptibility maps of the Kuzulu landslide area and its near vicinity. For this purpose, a detailed landslide inventory map was prepared and geology, slope, aspect, elevation, topographic-wetness index and stream-power index were considered as conditioning factors. During the susceptibility analyses, the conditional probability approach was used and a landslide-susceptibility map was produced. The landslide-susceptibility map will help decision makers in site selection and the site-planning process. The map may also be accepted as a basis for landslide risk-management studies to be applied in the study area.     

Anisotropic damage of rock joints during cyclic loading: constitutive framework and numerical integration

This work describes a constitutive framework for modeling the behavior of rough joints under cyclic loading. Particular attention is paid to the intrinsic links between dilatancy, surface degradation, and mobilized shear strength. The framework also accounts for the important effect of shear‐induced anisotropy. The resulting approach is fully three‐dimensional and is not restricted to plane‐displacement kinematics. Both the governing formulation and an algorithm for implicit numerical integration are presented. While the proposed methods are general, we also postulate a specific model that is compared with experimental data. It employs relatively few free parameters but shows good agreement with laboratory tests. Copyright © 2013 John Wiley & Sons, Ltd.     

A new standardized Palmer drought index for hydro‐meteorological use

Accepting the concept of standardization introduced by the standardized precipitation index, similar methodologies have been developed to construct some other standardized drought indices such as the standardized precipitation evapotranspiration index (SPEI). In this study, the authors provided deep insight into the SPEI and recognized potential deficiencies/limitations in relating to the climatic water balance it used. By coupling another well‐known Palmer drought severity index (PDSI), we proposed a new standardized Palmer drought index (SPDI) through a moisture departure probabilistic approach, which allows multi‐scalar calculation for accurate temporal and spatial comparison of the hydro‐meteorological conditions of different locations. Using datasets of monthly precipitation, temperature and soil available water capacity, the moisture deficit/surplus was calculated at multiple temporal scales, and a couple of techniques were adopted to adjust corresponding time series to a generalized extreme value distribution out of several candidates. Results of the historical records (1900–2012) for diverse climates by multiple indices showed that the SPDI was highly consistent and correlated with the SPEI and self‐calibrated PDSI at most analysed time scales. Furthermore, a simple experiment of hypothetical temperature and/or precipitation change scenarios also verified the effectiveness of this newly derived SPDI in response to climate change impacts. Being more robust and preferable in spatial consistency and comparability as well as combining the simplicity of calculation with sufficient accounting of the physical nature of water supply and demand relating to droughts, the SPDI is promising to serve as a competent reference and an alternative for drought assessment and monitoring. Copyright © 2013 John Wiley & Sons, Ltd.     

1∶10000图库一体化数据的质量控制

根据1∶10 000图库一体化数据成果,对图库一体化数据生产过程中各个环节的质量控制进行探讨,提出了一体化数据的质量控制方法。     

The behavior of a multilayered porous thermo-elastic medium with anisotropic thermal diffusivity and permeability

With the aid of integral transform techniques, this paper presents an extended precise integration solution for thermal consolidation problems of a multilayered porous thermo-elastic medium with anisotropic thermal diffusivity and permeability due to a heat source. From the fundamental governing equations, ordinary differential equations are derived by employing Laplace–Hankel transforms. By applying the extended precise integration method, equations in the transformed domain can be solved, and the actual solutions are further obtained by adopting a numerical inverse transformation. The accuracy and feasibility of the proposed theory is demonstrated by contrastive analysis with existing studies. Finally, several examples are carried out to investigate the influence of heat source’s type, axial distance, burial depth of heat source, ratio of thermo-permeability, permeability anisotropy, thermal diffusivity anisotropy and stratification on the thermal consolidation process.     

年最大值抽样估算的暴雨频率设计值的低估问题探讨

由年最大值抽样（AMS）和年超大值抽样（AES）的基本理论及重现期（RP）的定义可知,AMS并不符合以“事件”为基础的重现期的定义.以美国西南半干旱区1438个雨量站和太湖流域96个雨量站的降雨资料为例,通过经验频率与超过概率的比较,发现AMS估算的暴雨频率设计值偏小,尤其是对常遇频率降雨设计值的影响更加显著.美国的降雨量资料站点多、系列长,实际资料验证与理论分析一致.通过对太湖流域AMS资料的分布形态进行分析的结果表明：太湖流域的站点不多,资料长度不够,且大部分站点在雨量大值区数据稀少,使得频率直方图不连续,是造成我国太湖流域的资料验证效果不理想的可能原因.     

遥感数据融合的进展与前瞻

数据融合是提升遥感影像应用能力的重要手段,一直是遥感信息处理与应用领域的研究热点。本文系统综述了遥感数据融合的进展与前瞻:首先对数据融合的层次与分类进行了总结和归纳,将遥感数据融合划分为同质遥感数据融合、异质遥感数据融合、遥感—站点数据融合、遥感—非观测数据融合4大类;在此基础上,重点针对时—空—谱光学遥感数据的融合,从多视超分辨率融合、多尺度融合、空—谱融合、时—空融合、时—空—谱一体化融合等方面进行了详细阐述;最后总结了遥感数据融合的前瞻研究方向,包括时—空—谱一体化融合的拓展、空天地观测数据的跨尺度融合、传感网环境下的在线融合、面向应用的融合方法等。