Water quantity-quality combined evaluation method for rivers＇ water requirements of the instream environment in dualistic water cycle： A case study of Liaohe River Basin

In this article the meaning of the quantity and quality of environmental flows of river in dualistic water cycle is discussed, and compared with the meaning of unitary water cycle. Based on the analysis of the relationship between environmental flows of river requirements, the efficiency of water resource usage, the consumption coefficient, and the concentration of waste water elimination, the water quantity and water quality calculation method of the environmental flows of river requirements in dualistic water cycle is developed, and the criteria for environmental flows of river requirements are established, and therefore the water quantity-quality combined evaluation of natural river flows requirements are realized Taking the Liaohe River as a model, the environmental flows of river requirements for Xiliao River, Dongliao River, mainstream Liaohe River, Huntai River and northeast rivers along the coasts of the Yellow and Bohai seas in unitary water cycle are calculated, each taking up 39.3%, 63.0%, 43.9%, 43.3% and 43.5% of runoff respectively. Evaluated according to Tennant recommended flow, the results show that： except Xiliao River is ＂median＂, the rest are all upon ＂good＂, the Dongliao River is even ＂very good＂. The corresponding results in dualistic water cycle are that, the proportion of natural flows for each river is 57.5%, 74.1%, 60.8%, 60.3% and 60.4%; while the combined evaluation results show that： considering ＂quantity＂, except Xiliao River, the rest rivers can all achieve the ＂quantity＂ criteria of the en- vironmental flows of river requirements, but if considering the aspect of ＂quality＂, only Dongliao River can reach the ＂quality＂ standard. By water quantity-quality combined evaluation method, only Dongliao River can achieve the criteria. So the water quality is the main factor that determines whether the environmental flows can meet the river ecosystem demands.     

降雨径流的机制分析

根据太谷均衡实验站人工模拟降雨实验资料及收集的资料,初步分析降雨产流的全过程,对包气带土壤水分运动特征、降雨入渗的规律、径流形成的条件及降雨径流诸要素平衡,作了概略性的阐述,对降雨产流机制做了深入的分析.     

石河子市地下水资源可持续利用探讨

石河子市经过三十多年的大规模开发建设,市区地下水位一直在持续下降,对目前持续下降的市区地下水的开发状况应如何看待,作者对地下水可开采资源量提出新的评价底限,意在抛砖引玉,吸引同仁对如何贯彻"水资源的可持续利用保障可持续发展"、更好地为城市建设服务出谋划策.     

南阳市城区浅层地下水动态研究

在深入研究河南省南阳市城区浅层地下水水文地质条件的基础上、评价了地下水水质现状,通过地下水位动态、地下水漏斗现状分析和对水量均衡计算,提出了南阳市城区浅层地下水处于动平衡状态的结论.     

高寒地区渠道防治冻害技术措施

依据黑龙江省水利科学研究院近20年来水工建筑物抗冻技术研究的主要成果,简述了高寒地区渠道防治冻害技术的主要内容,包括:抗冻胀设计参数的确定方法、渠道衬砌工程防治冻害技术措施的要点等,可供工程设计人员参考。     

构造趋势法计算剥蚀量的计算机实现

剥蚀量的计算是盆地非连续沉降沉积模拟过程中一个非常重要的问题,通过量化模式分析,将构造趋势法计算剥蚀量在计算机上得以实现,并在实际应用中取得较好效果。     

纵向岭谷作用下云南热量的时空特征

应用主分量分析(PCA)、统计分析及非整波求功率谱方法对云南省125站1971-2003年主要热量指标的时空特征及成因进行分析.结果表明:(1)纵向岭谷地形的"阻隔-通道"作用,使云南温度的纬向分布规律被破坏,经向分布规律比较明显,空间分布极不均匀;(2)纵向岭谷作用下云南热量地域分布差异显著,南部热量丰富,北部欠缺,西部比东部丰富,河谷地区热量最丰富,滇西北及山区热量最贫乏;(3)6、7月热量最丰沛,1月最为贫乏,春季热量好于秋季;(4)近30 a云南年平均气温有明显的上升趋势,存在明显的7 a、11 a、18 a周期振荡;(5)云南年平均气温具有大范围位相一致的变化趋势及东部冷(暖)与西部暖(冷)的变化类型.     

Hazard rate estimation of a mixture model with censored lifetimes

This paper is intended to compare the hazard rate from the Bayesian approach with the hazard rate from the maximum likelihood estimate (MLE) method. The MLE of a parameter is appropriate as long as there are sufficient data. For various reasons, however, sufficient data may not be available, which may make the result of the MLE method unreliable. In order to resolve the problem, it is necessary to rely on judgment about unknown parameters. This is done by adopting the Bayesian approach. The hazard rate of a mixture model can be inferred from a method called Bayesian estimation. For eliciting a prior distribution which can be used in deriving a Bayesian estimate, a computerized-simulation method is introduced. Finally, a numerical example is given to illustrate the potential benefits of the Bayesian approach.     

一次区域性暴雪天气成因分析

分析了2001年1月6日河南省中北部出现的区域性暴雪天气过程中天气系统的演变、物理量场,并对数值预报产品作出天气学解释。     

Water problems in Gaza Strip,Palestine

The only source for water in Gaza strip, southern Palestine, is the groundwater aquifer. The Pliocene - Pleistocene aquifer has two serious problems: quantity and quality. This study is an attempt to identify the problems and to suggest solutions for water problems in Gaza strip. In addition, some rules for rehabilitation of the aquifers were suggested.