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Ke‐Sheng Cheng Irene Hueter En‐Ching Hsu Hui‐Chung Yeh 《Journal of the American Water Resources Association》2001,37(3):723-735
Abstract. Hyetographs are essential to many hydrological designs. Many studies have shown that hyetographs are specific to storm types and durations. Recent work presented evidence that dimensionless hyetographs are scale invariant. We show that the simple scaling property of rainfall guarantees that the normalized rainfall rates of different storm durations are identically distributed and propose a nonstationary Gauss‐Markov model based on the annual maximum events that arise from the dominant storm type. We derive the unique estimators for the parameters of the Gauss‐Markov model under two constraints that: (a) the typical peak rainfall rate is preserved, and (b) the most likely hyetograph is obtained. One attractive feature of this model is that it allows translating hyetographs between storms of different durations. Two examples illustrate our model. 相似文献
293.
ABSTRACT: Economic values of riparian buffers in a watershed are evaluated by the changes in the net economic return for farming with and without riparian buffers when achieving the same water quality objectives. The simulated water quality impacts of alternative farming systems using SWAT and experimental data for riparian buffers are used in a mathematical optimization model to estimate net economic return for farming subject to a water quality objective. Physical characteristics such as stream length, channel slope, average land slope, cropland percentage and several soil attributes are identified in the watershed using ARC/INFO GIS. A regression model is then used to evaluate the impacts of these physical characteristics on the estimated economic values of buffers. The study is conducted in Goodwater Creek watershed, Missouri. The results show the estimated economic value of buffers is significantly affected by some soil properties, stream length, and cropland percentage in watershed and can be used to improve the effectiveness of riparian buffers at watershed and regional levels. 相似文献
294.
处理抗生素废水的厌氧复合床反应器单体有效容积为500 m3,根据反应器中有机物降解和细胞合成的关系,建立了进料有机负荷模型Mn=(1+k)n-1M1和进料容积负荷模型Nn=(1+k)n-1N1.根据启动过程中细菌的生长特性和进料有机负荷模型的计算,提出了厌氧复合床反应器启动运行的进料负荷技术方案,成功地进行了厌氧复合床处理抗生素废水的生产性启动. 相似文献
295.
陈雄新 《湖南环境生物职业技术学院学报》2008,14(3):17-19
对数据做统计描述和方差分析的方法很多,通过电子表格Excel软件进行统计描述和方差分析,为研究者提供了方便快捷的分析手段.Excel软件对于非统计专业人员的确是一个易学、易用、高效的好帮手.图7,表1,参5. 相似文献
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Jennifer A. Curtis Lorraine E. Flint Michelle A. Stern 《Journal of the American Water Resources Association》2019,55(3):740-758
A multi‐scale soil moisture monitoring strategy for California was designed to inform water resource management. The proposed workflow classifies soil moisture response units (SMRUs) using publicly available datasets that represent soil, vegetation, climate, and hydrology variables, which control soil water storage. The SMRUs were classified, using principal component analysis and unsupervised K‐means clustering within a geographic information system, and validated, using summary statistics derived from measured soil moisture time series. Validation stations, located in the Sierra Nevada, include transect of sites that cross the rain‐to‐snow transition and a cluster of sites located at similar elevations in a snow‐dominated watershed. The SMRUs capture unique responses to varying climate conditions characterized by statistical measures of central tendency, dispersion, and extremes. A topographic position index and landform classification is the final step in the workflow to guide the optimal placement of soil moisture sensors at the local‐scale. The proposed workflow is highly flexible and can be implemented over a range of spatial scales and input datasets can be customized. Our approach captures a range of soil moisture responses to climate across California and can be used to design and optimize soil moisture monitoring strategies to support runoff forecasts for water supply management or to assess landscape conditions for forest and rangeland management. 相似文献
298.
简要统计了2015年1-2月国内发生的各种环境事件86起,包括沙尘天气7起,污染事件15起,地震46起,山体滑坡和泥石流6起,旱灾2起以及其他自然灾害10起. 相似文献
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在低放射性环境样品进行测量时,要求测量仪器具有较好的稳定性。仪器在工作一段时间后,要了解所作的测量数据是否具有统计重复性,仪器指标发生的变化是否在统计基础上,仪器工作是否正常,绘制仪器质量控制图是一种有效方法。通过绘制质量控制图表的方法,可随时了解仪器的稳定性和仪器的技术指标,直观地展示出测量过程是否处于统计控制中。以确保仪器的测量精度。 相似文献