HYDROLOGIC MODELING OF TWO GLACIATED WATERSHEDS IN NORTHEAST PENNSYLVANIA1

ABSTRACT: A hydrologic modeling study, using the Hydrologic Simulation Program - FORTRAN (HSPF), was conducted in two glaciated watersheds, Purdy Creek and Ariel Creek in northeastern Pennsylvania. Both watersheds have wetlands and poorly drained soils due to low hydraulic conductivity and presence of fragipans. The HSPF model was calibrated in the Purdy Creek watershed and verified in the Ariel Creek watershed for June 1992 to December 1993 period. In Purdy Creek, the total volume of observed stream-flow during the entire simulation period was 13.36 × 10⁶ m³ and the simulated streamflow volume was 13.82 × 10⁶ m³ (5 percent difference). For the verification simulation in Ariel Creek, the difference between the total observed and simulated flow volumes was 17 percent. Simulated peak flow discharges were within two hours of the observed for 30 of 46 peak flow events (discharge greater than 0.1 m³/sec) in Purdy Creek and 27 of 53 events in Ariel Creek. For 22 of the 46 events in Purdy Creek and 24 of 53 in Ariel Creek, the differences between the observed and simulated peak discharge rates were less than 30 percent. These 22 events accounted for 63 percent of total volume of streamflow observed during the selected 46 peak flow events in Purdy Creek. In Ariel Creek, these 24 peak flow events accounted for 62 percent of the total flow observed during all peak flow events. Differences in observed and simulated peak flow rates and volumes (on a percent basis) were greater during the snowmelt runoff events and summer periods than for other times.     

Use of a generalized linear model to evaluate range forage production estimates

Interdisciplinary teams have been used in federal land planning and in the private sector to reach consensus on the environmental impact of management. When a large data base is constructed, verifiability of the accuracy of the coded estimates and the underlying assumptions becomes a problem. A mechanism is provided by the use of a linear statistical model to evaluate production coefficients in terms of errors in coding and underlying assumptions. The technique can be used to evaluate other intuitive models depicting natural resource production in relation to prescribed variables, such as site factors or secondary succession.     

太湖流域水灾演变与环境变迁的相关分析

新石器时期以来,太湖地区的水灾发生机制和表现形式严格受控于海、地、气系统的能量均衡和转换过程,具有明显的阶段性特征,遵循由海洋优势性向海面控制基准下陆源洪水的演变过程.愈接近现代,成灾和干扰因素愈趋复杂,逐渐呈现出水灾与环境相互反馈使水灾加深(岗身体系形成并完善,太湖形成并扩张以来),以及人类活动、水灾与环境三者间相互反馈使水灾频度加大等趋势(尤其自南宋以来).提出了相对高海面的水灾控制基面效应和太湖水灾扩张效应等观点.     

田湾核电温排水遥感监测与数模一致性分析

利用温度反演和数值模拟的方法,对田湾核电站航天遥感测量和数值模拟结果作对比分析。结果显示:遥感监测和数值模拟结果在田湾核电站附近海域的海面温度场羽迹展布方向、不同季节大小潮型、潮态规律上都是相似的,只是在规模和数量上存在着一定差异,两者可以相互验证。     

SFLA-Verhulst组合模型预测矿井瓦斯涌出量

针对矿井瓦斯涌出量的时变性、波动性、非线性以及不确定性等特征,提出了SFLA-Verhulst组合预测模型,用于对具有非线性动态特征的瓦斯涌出量进行预测。该模型通过蛙跳算法对Verhulst模型的背景值参数寻优,并引入一次指数平滑法对原始数据进行优化处理,建立了基于混合蛙跳算法的SFLA-Verhulst组合预测模型;结果使模型在原始数据不准确或存在误差干扰的情况下仍能进行精度较高的预测。将新模型应用于某矿瓦斯涌出量预测,并对模型的预测结果进行检验分析,结果表明:该模型在结合蛙跳算法的全局寻优特点后预测精度较传统的GM(1,1)模型有明显的提高,适用性更强。     

基于GIS淹没模型的城市道路内涝灾害风险区划研究

在求取襄阳中心城区重现期雨量与可抽排雨量的基础上,采用基于GIS暴雨洪涝淹没模型计算不同重现期致灾雨量的淹没水深和范围;依据城市内涝对道路的实际影响,制作城市道路内涝灾害风险区划图。结果表明,该方法能够直观表达研究区域内不同雨量阈值的内涝灾害淹没风险分布,定量评估淹没水深、淹没范围。同时给出了城市道路内涝灾害风险区划图,结合城市道路信息,准确定位高风险易涝街区,为政府部门决策提供科学依据。     

How many samples are required? Evaluating a model for verification of carbon sequestration in a hybrid poplar buffer strip

A model is developed to predict annual and total above-ground carbon storage within a hybrid poplar stream buffer. The regression model predicts tree wet weight based upon circumference at breast-height (137 cm) with an r-square value of 0.9922. Carbon storage in above-ground biomass is estimated to be 3.57 to 3.71 metric tons per hectare, with a measured annual increment of 0.92 to 1.37 metric ton per hectare per year. The variability of carbon storage within this biological system, including soil organic matter, is explored, and the number of samples required to achieve a desired level of statistical certainty are predicted. As has been investigated previously for other biological systems (Garten and Wullschleger, 1999), the study shows that a prohibitively large number of samples must be taken in order to achieve high degrees of certainty about mean carbon storage values. The study also shows, however, that mean values with somewhat greater uncertainties can easily be achieved with much smaller sample sizes. Thus carbon sequestration verification might be accomplished cost-effectively if the degree of certainty required is not unrealistically high for highly variable natural systems.     

长期贮存枪械性能综合评定方法

目的研究长期贮存枪械性能综合评定方法。方法综合调研,研究建立枪械长期贮存性能综合评定指标体系,依据指标体系,确定数据采集项目,获得枪械长贮性能基础数据,结合失效阈值与贮存寿命指标,综合评估枪械贮存性能。结果形成的评定方法包括评定原理、合格判据、指导原则、评定步骤等4个方面。结论该方法适用于新研枪械的长贮环境适应性设计与改进、长贮枪械的寿命指标考核与验证。     

基于系统工程过程论验证和确认

为了解析工程过程验证和确认之间的关系,明确两者的作用和方法。对两个概念的形成溯源、异同比较、关系分析、方法应用等角度展开分析和论述。验证和确认是系统工程过程中非常重要的两个技术过程,两个过程中的若干活动的方法比较相似,甚至相同,容易引起混淆。分析结果表明,两者目的不同,方法相似。验证(Verification)和确认(Validation)是系统工程的技术过程中非常重要的两个子过程,是整体过程中的不可缺少的两个环节,区别在于验证过程是确定设计过程和结果是正确的,确认过程则是确定所设计的对象是正确的,是符合利益相关方需求的。     

车辆强电磁脉冲条件下的分层防护及验证方法探讨

目的提高地面整车装备在强电磁脉冲环境中的生存能力,研究高场强条件下的分层电磁防护技术。方法研究强电磁脉冲干扰的车辆耦合途径,在综合考虑车辆生存能力、功能任务、费效比等因素的前提下,探讨从元器件级、设备分系统级、整车级进行电磁防护的方法,并提出验证方法。结果提出了基于分层的电磁防护措施,探讨了外部射频电磁环境适应性测试和电缆束瞬态传导敏感度测试等验证方法。结论要提高地面整车装备在强电磁脉冲环境中的生存能力,应当继续研究强干扰条件下的分层电磁防护技术,并通过整车试验进行防护效能验证。