Coupling typhoon rainfall forecasting with overland-flow modeling for early warning of inundation

Taiwan suffers from an average of three or four typhoons annually, and the inundation caused by the heavy precipitation that is associated with typhoons frequently occurs in lowlands and floodplains. Potential inundation maps have been widely used as references to set up non-structural strategies for mitigating flood hazards. However, spatiotemporal rainfall distributions must be addressed to improve the accuracy of inundation forecasting for emergency response operations. This study presents a system for 24-h-ahead early warning of inundation, by coupling the forecasting of typhoon rainfall with the modeling of overland flow. A typhoon rainfall climatology model (TRCM) is introduced to forecast dynamically the spatiotemporal rainfall distribution based on typhoon tracks. The systematic scheme for early warning of inundation based on the spatiotemporal downscaling of rainfall and 2D overland-flow modeling yields not only the extent of inundation, but also the time to maximum inundation depth. The scheme is superior to traditional early warning method referring to the maximum extent and depth of inundation determined from conditional uniform rainfall. Analytical results show that coupling TRCM with an overland-flow model yields satisfactory inundation hydrographs for warning of the extent and peak time of inundation. This study also shows that the accuracy of forecasting spatiotemporal rainfall patterns determines the performance of inundation forecasting, which is critical to emergency response operations.     

二次判别函数在油气水层解释中的应用

在油田的勘探与开发过程中,每口井完钻后都要进行油矿地球物理的测井工作,以确定井下地质剖面的岩石学类别,划分出渗透性和非渗透性地层,并指出渗透性地层中所含的是油、气或是水。     

西部缺水地区多样化水资源开发模式探讨

最近我国政府提出了西部大开发的战略决策。发展西部地区首要任务是研究解决水资源缺乏问题。40多年来南京大学在地下水探寻和开发、水资源评价和水污染的模拟等方面取得了系统研究成果。特别是运用新构造理论和优势面理论 ,在地下水资源探寻的研究中取得显著成效 ,近几年来作者提出的缺水山区水资源多样化开发模式研究课题 ,在河北顺平严重缺水区取得初步突破。这对于解决西部的水资源匮乏问题 ,促进西部大开发会具有重要的实际意义。     

Geotechnical design parameter evaluation using the alluvial plain characteristics in southeastern Iraq

Geotechnical construction is responsible for the overall stability of superstructures, and if there are design errors, the structure will be exposed to potential problems. Geotechnical design starts with the correct interpretation of the target ground. Southeastern Iraq is mainly comprised of an alluvial plain with diverse geological features, and, therefore, geotechnical design requires a detailed interpretation and understanding of the area. This paper reports on laboratory and field tests and in-depth analyses conducted on these alluvial plains. The results reveal that the upper layer of this area is highly over-consolidated. This may have been caused by the removal of overburden pressure as a result of glaciation and desiccation. The highly over-consolidated soils caused considerable sample disturbance by swelling the bored sample; this provided less reliable results. However, the cone penetration test was regarded as the most appropriate field assessment method for deriving sensible geotechnical design parameters. Despite its limitations in clayey soils, the standard penetration test provided results that matched well with previous observations due to the high penetration resistance of the highly over-consolidated ground. Down-hole tests and plate load tests were considered less reliable methods due to their limited applicability in this area. This study considers geographical features, laboratory methods, and empirical correlations from in situ tests, and, therefore, provides a well-summarized guideline to evaluate special geotechnical characteristics of the alluvial plain in southeastern Iraq.     

水中爆破地震动强度计算方法的研究

介绍了爆破地震动强度的主要因素及经验公式 ,分析了利用最小二乘法求场地系数K、α值方法的不足之处 ,提出最大似然法求解K、α值的新思路 ,并用实例证明了其具有更高的预测准确度     

Physical,chemical, and biological conditions associated with the early stages of the Lake Michigan vernal thermal front

An investigation of the thermal front in southeastern Lake Michigan during April 1988 revealed a dynamic physical, chemical, and biological environment. The front was observed approximately 4 km from the coast as a distinct gradient separating cold open-lake waters from warmer nearshore waters. Surface isotherms near the front were generally parallel to one another but skewed with respect to shore. Comparison between April 22 and 29 showed that the surface isothern pattern was modulated by wind stress. The pattern from April 29 showed signs of flow instabilities with horizontal scales of 1 km to 5 km. Surface drifter trajectories provided estimates of horizontal convergence at the fron which varied from 7×10^?6 s^?1 to 20×10^?6 s^?1. Inferred rates of downwelling, which ranged from 9.5 m d^?1 to 20.7 m d^?1, were sufficient to move a water parcel from the surface to the bottom in 2 to 6 d at the front. Convergent circulation was observed on both sampling dates despite contrasts in wind stress. Concentrations of chloride, soluble silica, and chlorophyll, which were always higher inshore, were 5% to 82% larger than offshore mean values. The aquatic environment just inshore of the thermal front was characterized by chlorphyll concentrations which exceeded 5.0 μg 1^?1 while concentrations offshore were between 1.0 μg 1^?1 and 2.0 μg 1^?1. A relatively uniform vertical structure in chlorophyll concentrations in the frontal zone was consistent with the observed convergence and inferred downwelling near the front.     

乌兰布和沙漠东南缘湖泊群消涨与驱动因素

湖泊是对环境变化响应敏感的地理单元,湖泊消长与响应机制研究对维持区域生态系统稳定具有重要意义。基于1999—2018年Landsat、气象、水文和农业种植面积等多种数据,在ArcGIS平台中利用改进归一化差异水体指数(MNDWI)及目视修正方法提取了乌兰布和沙漠东南缘湖泊群空间信息,运用统计学方法对主要驱动因子与湖泊消涨的关系进行了分析。结果表明:1999—2018年乌兰布和沙漠东南缘大湖泊(面积大于100 hm²)在面积上占优势,小湖泊(面积小于100 hm²)在数量占优势。趋势分析表明大湖泊面积和数量呈显著性减少趋势(相关系数分别为R=0.624 > R_18,0.01=0.561和R=0.648 > R_18,0.01=0.561);小湖泊减少趋势不显著。在空间分布格局上,研究区中部是大湖泊稳定分布区,大湖泊数量11~23个,面积2 208~4 581 hm²。研究区湖泊消长主要受到年实际引黄水量、农田面积和地下水埋深的影响。其中,实际引黄(河)水量影响所有湖泊(P≤0.01),而农田面积和地下水埋深分别对大湖泊(P≤0.01)和小湖泊(P≤0.05)影响显著。用这3个因子分别构建的多元回归模型显示,在大、小湖泊面积和数量预测方面,精度分别达到75.7%和60.5%以上。     

Bungalows, mansions and shophouses: Encounters in architourism

In architourism, tourists are attracted to places because of iconic buildings. Increasingly, non-iconic buildings of vernacular architectural styles are also appreciated by visitors as a way to authentically experience a place. This paper explores architourism in Malaysia and Singapore through the lens of historic boutique hotels. Geographical discourses in and methodologies of architectural geography are used to interrogate what these hotels mean for guests and hoteliers, and the effects on them too. Empirical findings deepen understanding of architourism through examining how ‘producers’ create culturally authentic environments in boutique hotels, and how ‘consumers’ utilise hotels to experience local cultures. The dual focus on production and consumption is in-line with critical architectural geography’s insistence on exploring the rhetoric of building design as well as the realities of their everyday uses and users.