Characteristics of spatial distribution of debris flow and the effect of their sediment yield in main downstream of Jinsha River,China

Debris flow hazard posts a big threat to the main downstream of Jinsha River where a number of huge power stations are under construction. The characteristics of spatial distribution of debris flows and the effect of their sediment yield on the reservoir areas have been studied. An automatic recognition module was developed to extract the geometry of debris flow channels from remote sensing data. Spatial distribution pattern of debris flows is obtained through combining the inventory database and multi-source remote sensing investigation. The distribution of debris flows has high dependency on the various factors including geology, geomorphology, climate, hydrology and human economic activities. The debris flows distributed in the study area are characterized by group and pair distribution, uncompleted deposition fans, highly controlled by faults and tectonic activities, spatial variation between left bank and right bank, and different subdivisions. The sediment yield caused by debris flow activates is evaluated using multi-year observation data from numerous observation stations. Quantitative studies have been performed on the relationship between the sediment yield and the debris flow area. A relatively fix ratio of 2.6 (×10⁴ t/km²) has been found in different subdivisions of main downstream area which shows that the source of sediment discharged into Jinsha River primarily come from debris flow activities. Another ratio is evaluated to represent the transforming possibility of debris flow materials to bed-sediment load and suspended-sediment load in the river. Based on these findings, the potential effect of sediment yield caused by debris flows on reservoir areas is discussed. The zonation map shows the different effect of debris flow sediment on different dam site area which shows a good agreement with variation of debris flow spatial distribution.     

Evaluation of geological factors in characterizing fault connectivity during hydrocarbon migration: Application to the Bohai Bay Basin

Faults play an intricate role in hydrocarbon migration and accumulation since they can serve either as a conduit or a seal. Quantitative evaluation of fault opening/sealing properties requires the selection of valid and optimal parameters among numerous geological factors to characterize the hydraulic behaviors of faults. The present study focuses on the Chengbei Step-Fault Area in the Qikou Depression, Bohai Bay Basin, NE China, because hydrocarbon migration and accumulation in this area occurred in a relatively short period so that accumulated hydrocarbons can be used as an indicator to deduce hydraulic connectivity of a fault zone between two sites. Various geological parameters pertinent to a fault, such as burial depth, dip angle, throw, strike, percentage of sandstone of faulted intervals, fluid pressure in faulted mudstone, stress normal to the fault plane, and shale gouge ratio, are analyzed to assess their effectiveness in characterizing fault connectivity. An index, the fault-connectivity probability (N_p), is proposed to evaluate the possibility that a fault has been once serving as a migration pathway. The statistical relationship between N_p and any a geological parameter may be used to indicate the effectiveness of this parameter in characterizing the connectivity of a fault during hydrocarbon migration. The correlation coefficient of a relationship is a good indicator of the effectiveness; and the results are generally in agreement with qualitative assessments. Parameters representing a single geological factor are generally ineffective, whereas those representing implicitly or explicitly two or more factors, such as shale gouge ratio, stress normal to the fault plane, and fault opening index, are more effective.     

海洋测绘多媒体资料管理系统的设计与实现

通过整理分析已有海洋测绘资料、调研查询者检索需求,并结合数据库与Web技术,采用了分类管理、格式转换、资源共享、在线发布等一系列管理手段,实现了海洋测绘多媒体资料数据管理与发布的综合集成.     

前古典时期西方游记中的地理思想呈现——对马可波罗、哥伦布和达尔文游记的考察

游记作为一种特殊的文学形式,因其承载的时间和空间意义而兼具历史和地理的双重价值.通过对《马可波罗行纪》、《乘小猎犬号环球航行》和《哥伦布首航美洲——历史文献与现代研究》3本论著的定性式内容分析,比较了公元12、14、18世纪3个不同历史时期西方地理思想在空间认知、经济地理和政治地理三方面的差别和特点,并尝试探究公元12...     

长三角地区旅游城市体系组织秩序信息维数研究

对长三角地区旅游城市体系的旅游功能进行量化处理,采用分形方法研究其组织秩序来考察旅游城市体系对旅游活动的支撑作用,通过对长三角旅游城市体系组织秩序的信息维数的测算与分析,认为长三角地区旅游城市体系组织秩序具有较好的分形特征,系统结构比较紧致,各城市之间的整体性较好,对旅游活动的支撑作用较强.无论北部子系统还是南部子系统,上海在其体系中均具有很强的中心辐射作用,但也存在一定的差异,上海市对南部旅游城市体系旅游功能的加强程度要高于其在北部旅游城市体系中的作用.在目前条件下,上海还不足以带动整个长三角地区旅游城市体系整体性的提高,因此,加强上海的中心辐射作用,是使之成为实现长三角旅游城市一体化程度提高的重要途径.     

泰宁世界地质公园社区居民对旅游开发的影响感知研究

为了了解泰宁世界地质公园社区居民对旅游开发的影响感知情况,促进泰宁旅游业的可持续发展,本研究选取泰宁世界地质公园的金湖、寨下大峡谷、上清溪3个主要景区作为案例区,深入调查这3个景区周边社区居民(家庭参与旅游占81.75%)对旅游开发的影响感知情况.结果表明,泰宁县旅游开发处于初期阶段,居民对旅游影响的正面感知强于负面感...     

Hydrologic prediction for urban watersheds with the Distributed Hydrology–Soil–Vegetation Model

Some relatively straightforward modifications to the Distributed Hydrology–Soil–Vegetation Model (DHSVM) are described that allow it to represent urban hydrological processes. In the modified model, precipitation that falls on impervious surfaces becomes surface runoff, and a spatially varying (depending on land cover) fraction of surface runoff is connected directly to the stream channel, with the remainder stored and slowly released to represent the effects of stormwater detention. The model was evaluated through application to Springbrook Creek watershed in a partially urbanized area of King County, Washington. With calibration, the modified DHSVM simulates hourly streamflow from these urbanized catchments quite well. It is also shown how the revised model can be used to study the effects of continuing urbanization in the much larger Puget Sound basin. Model simulations confirm many previous studies in showing that urbanization increases peak flows and their frequency, and decreases peak flow lag times. The results show that the urbanization parameterizations for DHSVM facilitate use of the model for prediction and/or reconstruction of a range of historic and future changes in land cover that will accompany urbanization as well as other forms of vegetation change. Copyright © 2008 John Wiley & Sons, Ltd.     

綦江流域80a一遇特大暴雨实况与影响系统分析

利用常规气象观测资料、区域自动气象站观测资料、探空资料、风云2G资料、降水实况融合产品以及EC EAR 0.25°× 0.25°逐小时再分析资料,对2020年6月22日綦江地区特大暴雨洪灾过程进行诊断分析。结果表明,此次过程发生在南亚高压脊线附近,500 hPa槽前,700 hPa和850 hPa低涡切变之间,850~500 hPa之间为一致的偏南暖湿气流不断输送水汽,近地面层为偏东回流冷空气形成冷垫爬升;对流云团生成、合并、发展,形成中尺度对流系统MCS,对强降水有很强的指示意义,且暴雨区发生在云团合并发展阶段且冷云区≤-52 ℃的区域;短时强降水伴随地面辐合线的生成而发生,且最强小时雨强中心出现在中尺度辐合线附近并随着辐合线缓慢向东移动;此次过程累积雨量大值区主要发生在綦江城区及綦江流域上游地区,其中过程累积雨量最大的站点达到了302.7 mm,綦江流域上游地区的站点基本都达到100 mm以上,最大小时雨强达到了64 mm·h^-1,小时雨强强、累积雨量大是造成此次暴雨洪涝灾害的主要原因。     

黄土震陷系数与物性关系的研究

以Q3原状黄土为研究对象探讨了震陷系数与各种物理性指标的内在联系,采用多因素回归分析建立了震陷系数与含水量(W)、干密度(γd)、孔隙面积(A)、粘性含量(Pc)、初始动弹性模量(E0)的分析模型,构建了一个综合因子Y1代表上述5指标。结果显示震陷系数与物理指标间具有良好的相关性,其中天然含水量对震陷系数的总影响最大,干窖重次之。说明了原状黄土震陷性参数描述的合理性和基于物性指标参数关系的合理性。