基于分布式水文模拟的三峡区间洪水预报(Ⅰ)——模型构建及验证     

许继军  杨大文  蔡治国  金勇 《水文》2008,28(1):32-37

长江三峡区间因暴雨形成的洪水峰高量大,对三峡水库的防洪安全和运行调度的影响很大.本论文依据三峡地区的地形地貌特征,采用基于GIS的机理性分布式水文模型,来模拟三峡区间入库洪水,以尽量减少洪水预报中的不确定性.利用近期建成的78个自动雨量站网监测的小时降雨信息作为模型的输入,对模型参数进行了率定和验证,结果表明:大多数洪水过程的模拟精度较好,但也有的模拟结果较差,其中降雨信息缺失是洪水预报不确定性的主要来源.  相似文献   

浙江省小流域山洪灾害临界雨量确定方法分析   总被引：12，自引：2，他引：10  

叶勇  王振宇  范波芹 《水文》2008,28(1):56-58

小流域山洪灾害具有突发性,预测预警难度较大.本文结合浙江省小流域山洪灾害防御的实践经验,研究提出了以水位反推法计算临界雨量,简单实用,具有较好的实践价值和推广意义.  相似文献   

富P过铝质岩浆体系的研究现状及存在的问题     

唐勇  张辉  刘丛强  饶冰 《矿物学报》2008,28(1):35-42

高度演化的富P过铝质岩浆体系,具有鲜明的、不同于其他体系的地球化学行为.富P过铝质熔体以富P,高ASI,贫Fe、Mg、Ca,强烈亏损REE、Th、Y以及具有W、Sn、Nb、Ta等金属的矿化为特征.富P过铝质岩浆体系中的碱性长石为富P长石,长石中P可以有效地指示过铝质岩浆体系的演化历程;在岩浆演化的晚期,P与Li具强的亲和性,形成锂辉石-磷铝锂石-羟磷铝锂石的组合.已有的实验研究揭示,P能降低简单花岗岩的液相线和固相线温度、粘度以及增加H2O在熔体中的溶解度.然而,这一体系还存在许多问题亟待研究,P能否促进过铝质岩浆的液态不混溶,能否促使等价不相容元素在过铝质岩浆演化过程中的分异,是否在稀有金属成矿过程中起作用等都是值得关注的问题.  相似文献   

阿尔金南缘构造带西段辉绿岩墙群的地球化学特征及构造环境   总被引：5，自引：0，他引：5  

覃小锋  夏斌  李江  陆济璞  许华  周府生  胡贵昂  李乾 《岩石矿物学杂志》2008,27(1):14-22

对阿尔金南缘构造带西段辉绿岩墙群的岩石学和地球化学的详细研究表明,该区辉绿岩墙群为拉斑系列岩石,其主量元素以中等TiO2(1.19%～1.59%)、高MgO(5.51%～7.88%)、贫K2O(0.04%～0.84%)和P2O5(0.10%～0.20%)、Na2OK2O为特征;高场强元素(HFSE)丰度特征显示其为E-MORB型或过渡型玄武岩质岩石;稀土元素总量相对较高,轻重稀土元素分馏不显著[(La/Yb)N=1.93～3.61,LREE/HREE=3.01～4.10],在球粒陨石标准化配分模式图上呈略富集型.结合玄武岩构造环境判别图解综合分析推测,它们可能形成于一种裂谷向MORB环境过渡的构造环境,即初始小洋盆构造环境.  相似文献   

Linear magnetic anomalies and tectonic development of the middle Okinawa Trough     

Liang Ruicai  Wu Jinlong  Liu Baohu  Wang Yong  Wang Shugong 《海洋学报(英文版)》2001,20(1):105-116

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅＯｋｉｎａｗａＴｒｏｕｇｈ (ＯＴ) ,ｌｏｃａｔｅｄｎｏｒｔｈｗｅｓｔｏｆｔｈｅＲｙｕｋｙｕＴｒｅｎｃｈａｎｄｔｈｅＲｙｕｋｙｕｇｕｎｔｏ ,ｅａｓｔｏｆｔｈｅＥａｓｔＣｈｉｎａＳｅａｓｈｅｌｆ,ｉｓａｂａｃｋ ａｒｃｂａｓｉｎｂｕｌｇｅｄｔｏｔｈｅＲｙｕｋｙｕＴｒｅｎｃｈ .ＴｈｅＯＴｅｘｔｅｎｄｓｆｒｏｍＫｙｕｓｈｕｉｎｔｈｅｓｏｕｔｈｗｅｓｔｏｆＪａｐａｎｔｏｔｈｅＩｌａｎＰｌａｉｎｉｎｔｈｅｎｏｒｔｈｅａｓｔｅｒｎＴａｉｗａｎ ,Ｃｈｉｎａｉｎｔｈｅｓｏｕｔｈｗｅｓｔ…  相似文献   

Fluxes and sources of suspended organic matter in an estuarine turbidity maximum region during low discharge conditions   总被引：6，自引：1，他引：6  

Miguel A. Goni  Mary W. Cathey  Yong H. Kim  George Voulgaris 《Estuarine, Coastal and Shelf Science》2005,63(4):683-700

Water column concentrations of total suspended solids (TSS), particulate organic carbon (POC) and particulate nitrogen (PN) were measured at three different depths in four different locations bracketing the estuarine turbidity maximum (ETM) along the main channel of a temperate riverine estuary (Winyah Bay, South Carolina, USA). Measurements were carried out over full tidal cycle (over 24 h). Salinity, temperature, current magnitude and direction were also monitored at the same time throughout the water column. Tidally averaged net fluxes of salt, TSS, POC and PN were calculated by combining the current measurements with the concentration data. Under the extreme low river discharge conditions that characterized the study period, net landward fluxes of salt were measured in the lower part of the study area, suggesting that the landward transport through the main channel of the estuary was probably balanced by export out through the sides. In contrast, the net fluxes of salt in the upper reaches of the study area were near zero, indicating a closed salt balance in this part of the estuary. In contrast to salt, the net fluxes of TSS, POC and PN in the deeper parts of the water column were consistently landward at all four sites in Winyah Bay indicating the non-conservative behavior of particulate components and their active transport up the estuary in the region around the ETM.The carbon contents (%POC), carbon:nitrogen ratios (org[C:N]a) and stable carbon isotopic compositions (δ¹³C_POC) of the suspended particles varied significantly with depth, location and tidal stage. Tidally averaged compositions showed a significant increase up the estuary in the %POC and org[C:N]a values of suspended particles consistent with the preferential landward transport of carbon-rich particles with higher vascular plant debris content. The combination of tidal resuspension and flood-dominated flow appeared to be responsible for the hydrodynamic sorting of particles along the estuary that resulted in denser, organic-poor particles being transported landward less efficiently. The elemental and isotopic compositions indicated that vascular C₃ plants and estuarine algae were the major sources of the particulate organic matter of all the samples, without any significant contributions from salt marsh C₄ vegetation (Spartina alterniflora) and/or marine phytoplankton.  相似文献   

合浦珠母贝26S蛋白酶体S4,S7亚基基因片段的分离与分析     

姜铁民  张勇  黄洁  谢莉萍  吴移谋  张荣庆 《海洋科学》2003,27(4):28-34

26S蛋白酶体是真核生物中一种具有ATP依赖性的蛋白酶复合体,主要通过泛肽途径选择性降解细胞内与代谢调控、细胞周期有关的功能蛋白及异常蛋白,参与多种细胞活动的调控过程。26S蛋白酶体由具有催化活性的20S亚复合体和一个具有调节作用的19S亚复合体组成,其中19S亚复合体中的ATP酶亚基是调节26S蛋白酶体活性的重要组件。本通过简并引物PCR手段,从软体动物合浦珠母贝(Pinctada fucata)中扩增到参与构成19S亚复合体的S4和S7(MSS1)两个亚基的基因片段。这两个基因片段所编码的ATP酶组件包含有Gx4GKT,DEID,SAT和H／QRxGRxxR等26S蛋白酶体ATP酶亚基的共同功能基序。这是首次在软体动物中报道26S蛋白酶体的ATP酶亚基基因序列,为研究软体动物中26S蛋白酶体的结构与功能奠定了分子基础。  相似文献   

太湖表面定振波的数值计算和最大熵谱分析   总被引：1，自引：0，他引：1  

逄勇  濮培民 《海洋与湖沼》1996,27(2):157-162

利用水动力学方程对太湖表面的定振波进行计算，算得定振波周期约为４５２ｍｉｎ，另外，利用１９９２年８月２９－３１日在太湖西山观测到的水位资料，采用最大熵谱法，分析太湖表面的定振波，得周期值约为４５０ｍｉｎ。计算和分析的周期值基本吻合，取熵谱分析结果得太湖表面的单节点定振波周期值为４５０ｍｉｎ。  相似文献   

Nonlinear tidal waves in a kind of estuary with gradually varying cross-section     

Du Yong  Chen Zongyong  Ye Anle 《海洋学报(英文版)》1990,9(1):37-50

-Nonlinear tidal waves in a kind of estuary are studied in the paper using one-dimensional nonlinear hydrody-namic equations with friction. The estuary has exponentially varying width B=B0 e-bx and uniform depth h. The one-dimensional hydrodynamic equations are solved by perturbation method. It was found that our solution included two special cases, Pelisenpeki's solution and Airy's solution. The former can be got by letting b=0 in our solutions, and the latter by setting 6 = 0 and f= 0 (f is linear frictional coefficient). In terms of the second-order solution, the physical mechanism of nonlinear tidal waves in estuaries with gradually varying cross-section is explored. It is shown that, under the assumption of linear friction coefficient, shallow water constituent waves consist of two parts, one is produced by shallow water nonlinear effect outside the estuary, the other is generated by shallow water nonlinear effect inside estuary. In addition, the physical mechanism of the residual tidal current and  相似文献   

大西洋中脊TAG热液活动区中热液沉积物的稀土元素地球？…   总被引：15，自引：0，他引：15  

曾志刚  翟世奎 《海洋地质与第四纪地质》1999,19(3):59-66

用ＩＣＰ－ＭＳ对ＴＡＧ热液活动区表层热液沉积物中６个块状硫化物样品进行了稀土元素分析。所有样品均表现出正Ｅｕ异常和ＬＲＥＥ相对富集的球粒陨石标准化配分模式,热液沉积物样品中稀土元素组成的变化是由于海底热液循环体系中热液流体和涨水不同程度混合作用的结果,  相似文献