最近邻法在水质综合评价中的应用

最近邻法是一种传统的基于实例的分类方法,将最近邻法应用到水质综合评价中,建立了最近邻模型,利用三峡库区城市江段13个监测断面的检测数据进行评价,评价结果表明,水体尚清洁,综合污染程度不严重.为验证最近邻法评价结果的有效性,对模糊综合评价法和最近邻法的评价结果进行比较,得到了较好的效果,具有推广价值.     

基于三阶段SM-DEA-Malmquist指数的长江经济带碳排放效率研究

碳排放问题近年来备受各界学者所关注。为评价长江经济带区域内碳排放绩效,本文结合非期望产出的三阶段SBM-DEA模型和Malmquist指数对2011~2019年长江经济带11省市碳排放效率测算及动静态分析,该模型剔除了环境因素和随机变量的影响,使得测算结果更加符合实际情况。研究表明:长江经济带碳排放绩效呈整体上升态势,且存在东部>中部>西部差异化特征,内部管理对碳排放效率提升的正向作用明显,加大东中西部地区的人才引入及技术交流频度,有助于提升碳排放效率。     

中国的世界第一水资源与亚洲季风动力学

中国天然的墨脱察隅大喇叭的南部开口达700km，是目前世界第一大河——亚马逊河口长度（240km）的两倍多；喇叭开口处年降水量高迟4500mm／a，也是亚马逊河（2000mm／a）的两倍多；全面覆盖印度洋的三条跨赤道暖湿水汽大值带和来自太平洋、印度洋的十八条输送暖湿水汽的热带江河深入青藏，共同形成全球最大水资源的基本架构。笔者认为，为战胜可能在2020年前后将发生持续十年的世界性大旱灾，应及时完成墨脱察隅大喇叭体系配套工程；巧妙拓展现有水汽通道，把高降水带自海拔4000m以下，移到海拔4000m以上；增加三江源的降水量；开掘青藏运河，超越亚马逊河，为世界三分之二人口供水，“构建和谐世界”。     

Friction term discretization and limitation to preserve stability and conservation in the 1D shallow‐water model: Application to unsteady irrigation and river flow

Friction is one of the relevant forces included in the momentum equation of the 1D shallow‐water model. This work shows that a pointwise discretization of the friction term unbalances this term with the rest of the terms in the equation in steady state. On the other hand, an upwind discretization of the friction term ensures the correct discrete balance. Furthermore, a conservative technique based on the limitation of the friction value is proposed in order to avoid unbounded values of the friction term in unsteady cases of advancing front over dry and rough surfaces. This limitation improves the quality of unsteady solutions in wet/dry fronts and guarantees the numerical stability in cases with dominant friction terms. The proposed discretization is validated in some test cases with analytical solution or with measured data and used in some practical cases. Copyright © 2007 John Wiley & Sons, Ltd.     

南康江整治工程洪潮组合水文分析

通过对南康江疏浚整治工程水文计算分析,介绍人海小河流在洪潮组合情况下水文计算的方法,归纳出计算过程中应把握的关键性问题．     

高密度电法在地下暗河探测中的应用—以石林诗玛溶洞为例

诗玛溶洞位于石林景区南东约3 km,具有较好的旅游区位优势。诗玛溶洞洞穴发育特征报道见于2003年,但受溶洞空间分布和地下暗河水流的影响,探明的范围较小,溶洞的走向不清,溶洞是否具有利用的价值不清。因此,为进一步了解诗玛溶洞的平面位置,利用溶洞随地下暗河分布的特点,布置20 m道间距的高密度电法工作。分析物探成果,了解溶洞顶端埋深和溶洞空间大小,经后期工作查证,在工作区范围内,物探推测地下暗河走向和溶洞空间特征正确,西面走向延伸1 200 m,东面延伸700 m,物探成果进一步明确了溶洞及地下暗河范围,高密度电法在地下暗河勘察中取得了较好的应用效果,诗玛溶洞具有开发利用价值。     

Temporal and spatial distribution of isotopes in river water in Central Europe: 50 years experience with the Austrian network of isotopes in rivers

The Austrian network of isotopes in rivers comprises about 15 sampling locations and has been operated since 1976. The Danube isotope time series goes back to 1963. The isotopic composition of river water in Central Europe is mainly governed by the isotopic composition of precipitation in the catchment area; evaporation effects play only a minor role. Short-term and long-term isotope signals in precipitation are thus transmitted through the whole catchment. The influence of climatic changes has become observable in the long-term stable isotope time series of precipitation and surface waters. Environmental ³H values were around 8 TU in 2015, short-term ³H pulses up to about 80 TU in the rivers Danube and March were a consequence of releases from nuclear power plants. The complete isotope data series of this network will be included in the Global Network of Isotopes in Rivers database of the International Atomic Energy Agency (IAEA) in 2017. This article comprises a review of 50 years isotope monitoring on rivers and is also intended to provide base information on the (isotope-)hydrological conditions in Central Europe specifically for the end-users of these data, e.g. for modelling hydrological processes. Furthermore, this paper includes the 2006–2015 supplement adding to the Danube isotope set published earlier.     

关于最速渡江路线的解析解和数值解

本文用变分法,在渡江者游速大小恒定、水流速度大小恒定或随水域均匀变化两种情况下,求得了最速渡江线路的解析解,并在此基础上求得了比参考文献更优的数值解。     

粤东地区的河流阶地

 依据广东东部超过32条河流、55处河流阶地、至少25个¹⁴C、热释光的冲积层测龄数据等情况,可知：粤东最多有6级河流阶地,最大阶地高度70 m且靠近现代主河床分布。从上游向下游第一级阶地明显变形：龙川县黎咀镇上游为常态阶地,黎咀镇下游至博罗县园洲镇为半埋藏阶地,园洲镇下游进入东江三角洲为埋藏阶地。而且该冲积物时代有渐新趋势,反映晚更新世河源地区的构造抬升较早或速率较快,中下游地区构造逐渐稳定或下沉。粤东至少有12处较典型的剥夷面砾石层。其特怔：① 分布海拔20～210 m,与当地剥蚀台地高度相似;② 位于当地级别最高、分布面积大的河流阶地上;③ 石岩镇玉律、平陵镇、东坑镇、水唇镇、龙母镇张坊等剥夷面砾石层由昔日河流形成,其谷中谷成为今日小河（只有狭窄河床河漫滩,或许有第一级河流阶地）,今昔河流发育相隔数十万年;④ 剥夷面有两个倾斜方向：流域内向河谷和向下游倾斜;总体上由南岭向南海倾斜。