The influence of dam and lakes on the Yangtze River streamflow: long‐range correlation and complexity analyses

Employing long‐range correlation, complexity features and clustering, this study investigated the influence of dam and lake‐river systems on the Yangtze River flow. The impact of the Gezhouba Dam and the lake systems on streamflow was evaluated by analysing daily streamflow records at the Cuntan, the Yichang and the Datong station. Results indicated no evident influence of the Gezhouba Dam on streamflow changes. Distinct differences in scaling behaviour, long‐range correlation and clustering of streamflow at the Datong station when compared with those at the Cuntan and Yichang stations undoubtedly showed the influence of water storage and the buffering effect of the lake systems between the Datong station and other two hydrological stations on streamflow in the lower Yangtze River basin. Decreased regularity, enhanced long‐range correlation and increased clustering of streamflow in the lower Yangtze River basin due to the effect of water storage of the lake systems were corroborated. Copyright © 2011 John Wiley & Sons, Ltd.     

The historically adjusted range and the historically rescaled adjusted range

It was remarked by Hurst in 1951 that the adjusted range gives the size of the smallest reservoir capable of providing a constant discharge equal to the mean inflow. Since that time this range and its rescaled modification, the Hurst range, have been widely discussed, not however primarily with a view to applying them to reservoir design problems, but rather on account of their possible relevance to the simulation of geophysical time series.Acknowledging the well-known conceptual weaknesses of adjusted ranges and the theoretical difficulties that inhibit their direct utilisation in the design and operation of real reservoirs, the authors argue that the interest displayed on ranges during the past few decades justifies the effort of eliminating one in particular of these weakness, namely their non-implementability as operating policies, a consequence of the fact that they can only be retrospectively evaluated. The paper proposes modifications in which the unknowable mean and standard deviation of future samples are replaced by the known mean and sample standard deviation of historical data, leading to the historically adjusted range and the historically rescaled and adjusted range. The latter is produced as an implementable approximation to Hurst's (1951) solution to the optimal reservoir problem.The expected values of the new ranges are evaluated and numerically tabulated.     

Lightning fatalities in Australia, 1824–1991

Information on fatalities from lightning strikes has been extracted from a specially compiled database on natural hazards in Australia. Records dating from 1803–1991 indicate that at least 650 persons have been killed by lightning strikes. Maps and charts show the percentages of victims with respect to age, sex, locality, activity, and other circumstances of the strike. The majority of the 650 fatalities recorded have occurred along the more populous southeastern coast. The overall death rate, from 1910–1989, is 0.08 per 100 000 population. The annual number of lightning fatalities has decreased with time, from a death rate of 0.21 in 1910–1919 to 0.01 in 1980–1989. This trend is more pronounced when population figures are taken into account. The group that has been most at risk in Australia is that of males aged 15–19, followed by males aged 20–34. The male:female ratio of victims has decreased with time but is not approaching equality, being 11.6 in 1910–1919 and 5.3 in 1980–1989. The diurnal and monthly occurrences of lightning fatalities peak at 12.00–18.00 hours and November-February respectively. About 86% of fatalities have occurred outdoors and 14% have occurred indoors. Approximately three-fifths of fatalities have been work-related, and the group of workers that has traditionally been most at risk is that of land-workers. Approximately one-fifth of fatalities have been recreation-related, although this proportion has been increasing with time. The recreational activities of water sports, golf, and cricket have had the greatest number of lightning fatalities. Comparisons are made between these data and the results of other similar studies, both in Australia and overseas.     

面向对象的语义数据模型及其在空间数据库中的应用

传统的数据库模型适合于表示数字字母数据,难以处理复杂的空间数据。面向对象的语义数据模型克服了传统数据模型的许多不足,越来越多地应用于计算机科学各个领域。本文先描述了面向对象的语义数据模型,然后介绍了建立于这种模型基础上的空间数据库实验系统 spobase。     

中国南极信息系统总体框架的构想与研究

本文根据现实需求和所面临的国际环境,以系统论、信息论、控制论为基本立足点,探讨了中国南极信息系统(CAIS)总体框架的构想以及如何建立CAIS的若干问题。文中阐述了建设CAIS与南极信息资源管理(AIRM)之间相辅相承的关系;描述了CAIS的概念结构和基本结构的框架模型;研究了总体框架及系统的基本特征;分析了基本结构的层次性和相关性。针对易造成信息系统脆弱性的各种问题,讨论了需采用的技术、研究方法、开发策略、应遵循的基本规律,指出CAIS的第一个实践目标是开发与编写基于ADIF(南极目录交换用格式)的南极数据目录和南极主题词表。     

A documental database of Papers in Chinese Seismological Journals （Englishedition）

Ａ　ｄｏｃｕｍｅｎｔａｌ　ｄａｔａｂａｓｅ　ｏｆ　Ｐａｐｅｒｓ　ｉｎ　Ｃｈｉｎｅｓｅ　Ｓｅｉｓｍｏｌｏｇｉｃａｌ　Ｊｏｕｒｎａｌｓ　（Ｅｎｇｌｉｓｈｅｄｉｔｉｏｎ）（高树心）（￥宋利萍）ＡｄｏｃｕｍｅｎｔａｌｄａｔａｂａｓｅｏｆＰａｐｅｒｓｉｎＣｈｉ...     

数字河流数据的自动综合

本文主要介绍了数据库中水系要素综合中河流的自动综合方法，尤其是对非结构化河网中河流的自动选取作了较为详细的论述，并通过数据库中一幅完整图幅的河流数据对文中介绍的自动综合方法进行了验证。     

煤矿地质信息系统

介绍了煤矿地质信息、系统的构成、各模块的性能、功能、自动绘图中各个技术难点的解决方法和途径以及系统的运行环境。该系统是地质测量信息系统中的地质子系统。它是在现有微机环境下开发的集数据管理、统计计算、制表、绘图、辅助决策于一体的计算机地质信息管理系统。     

在我国东部沿海修建地下水封石洞油库若干问题的探讨

随着我国大陆架油、气田不断被发掘、开采,石油储运问题已指日可待。我国海岸线的基岩岸约占全长的2/3以上,其中,块状结晶岩体又占基岩岸的一半以上,这就给水封油库的布置提供了良好的基础。在油库的选择和兴建中,应加强对建库岩体和主要结构面、地应力及其分布的充分研究,以期能对洞库稳定问题、地下水位及水量的合理确定问题有所裨盖、     

Long-term erosion on granitic roadcuts based on exposed tree roots

Exposed roots were used to estimate soil and bedrock erosion on the cut slopes of a 45-year-old road constructed in granitic soils of the Idaho Batholith. The original roadcut surface was defined by projecting a straight line from the toe of the cut past the end of the exposed root to the intersection of a straight line projected along the surface of the hillslope. A cross-sectioning technique was then used to determine erosion to the present roadcut surface. A total of 41 exposed root sites were used to estimate erosion on a 1350 m-long section of road. Average erosion was 1·0 and 1·1 cm/year for soil and bedrock respectively. Buttressing by tree roots caused lower erosion rates for soil as compared to bedrock. Both soil and bedrock erosion rates showed statistically significant correlations with the gradients of the original cut slope. The bedrock erosion data provide a reasonable estimate of the disintegration rate of exposed granitic bedrock exhibiting the weathering and fracturing properties common to this area. The road is located in a study watershed where long-term sediment yield data are available. Sediment data from adjacent study watersheds with no roads were compared to sediment data from the roaded watershed to estimate the long-term increase in sediment yield caused by the road. The increase amounts to about 2·4 m³/year. This figure, compared to the average annual on-site road erosion, provides an erosion to sediment delivery ratio of less than 10 per cent. Based on study results, road construction and maintenance practices are suggested for helping reduce roadcut erosion.