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1.
中小河流域水文预报时,由于流域水文资料缺乏,洪水发生时间短,传统的水文模型难以取得良好的效果.基于平通河流域研究了分布式水文模型DHSVM的建立过程、建模方式以及模型的结构和参数,探讨了分布式水文土壤植被模型在平通河流域的适用性.并结合平通河水文资料进行了数值模拟研究.结果表明,采用DHSVM模型能够较好的反映流域日径流水文过程,模拟的相对误差均在10%以下,模型在平通河流域具有一定的适用性;从模型的结构角度对结果产生的误差进行了探讨.  相似文献   

2.
考虑地表水地下水交换的分布式水文模型GISMOD开发与应用   总被引:1,自引:0,他引:1  
详细介绍了一个基于网格、考虑地表水-地下水转换的分布式水文模型GISMOD.该模型由预处理程序、空间插值模块、蒸散发模块、参数设置和径流模拟5个部分组成.GISMOD不仅考虑了蓄满产流和超渗产流2种产流机制,而且提供了3种空间插值方法和8种蒸散发计算方法,具有良好的适用性.该模型将流域在水平方向上划分为若干相同大小的网格,在垂向上把土壤概化为3层,并根据不同土地利用、土壤和岩石类型设置参数,按照水位流量关系式计算不同土层间的水流交换量.黑河流域的实例研究表明,模拟结果与实际情况基本一致,即黑河流域上游地区以表层水下渗为主,在中游地区地下水反补河流.从季节上看,补给水量和下渗水量呈现出相反的变化规律,当下渗水量较高时,补给水量相应减少.最后,将模拟径流量与莺落峡实测结果进行对比,不论在日尺度还是月尺度GISMOD均取得了较好的模拟效果.  相似文献   

3.
森林生态水文研究进展与发展趋势   总被引:6,自引:0,他引:6  
基于国内外近几十年森林生态水文学的研究成果,概述了森林生态水文学的发展历程,介绍了森林生态系统水文过程和流域水文过程以及生态水文模型等方面的最新研究进展.基于存在的森林生态水文过程研究不系统、缺乏水文过程对生态过程影响研究、生态水文的尺度限制、水文模型的研究仍不完善等问题,提出了加强多学科综合研究,生态系统水文过程和机理研究,水文尺度研究,生态水文与气候变化的研究;同时指明了重视恢复生态水文学的研究、生态水文与水环境的研究、生态水文与生态用水的研究、生态水文学与高新技术结合研究等生态水文的发展趋势和发展方向.  相似文献   

4.
针对气候-水文耦合模型采用的计算网格较粗,不能很好地描述小尺度陆面水文过程的不足,以美国萨斯奎那西支子流域为研究区域,构建了考虑水力传导度和降雨次网格空间非均匀性的区域气候-水文耦合模型,从而在较粗的计算网格中描述较细的小尺度次网格水文过程.数值模拟结果表明,考虑次网格水文过程的耦合模型精度更高,模拟径流过程与实测过程拟合更好,并且提高了模型对水文物理过程的代表性.  相似文献   

5.
在大量岩溶流域查勘及水文资料收集的基础上,分析了岩溶流域径流形成的物理过程,提出了相应的水文模型。这种以岩溶特征为解释的、以改进了的水箱串联形式表达的岩溶流域产汇流综合模型,概念明确,计算简单、适于在岩溶流域水文预报和水文分析中使用。  相似文献   

6.
黄河无定河流域是典型的黄土高原沟壑地区,水文时空变化大,观测站点有限,水文过程的非线性问题和人类活动影响问题比较突出.本文针对黄河无定河流域内不同尺度水文循环模拟问题,对作者开发的分布式时变增益水文模型进行了改进,拓展到了月、日、时三个时间尺度,应用于无定河内的大理河、小理河及岔巴沟三级不同空间尺度的流域.研究表明:分布式时变增益水文模型是水文系统非线性理论与分布式流域水文模拟结合的一种新途径,水文系统模拟的精度比较满意.该模型为分析土壤湿度的时空分布与变化以及人类活动的影响,提供了一种量化分析的有效工具.  相似文献   

7.
以系统论的观点,从内、外水源对地貌的影响以及地貌对水文过程的影响这两个方面,分析了喀斯特流域水文地貌过程-响应系统,从而揭示了喀斯特流域地貌与水文之间的相互影响,相互制约的关系。  相似文献   

8.
盐渍土区生态、水文过程及其耦合作用机制是当前盐渍化、次生盐渍化产生的根源。目前的研究主要是从土壤水盐动态、地表水文格局及其生态效应、生态地下水位、生态需水等角度对盐渍土区生态水文过程进行研究和探讨,尚未能揭示清楚盐渍土形成和演化的生态水文学机制。未来需要就生态、水文过程及其耦合作用机制,地表水、地下水以及土壤水之间的相互转化关系及其生态效应,基于生态水文过程的生态需水,以及构建流域尺度盐渍化生态水文模型等进行深入研究,以便为盐渍土区生态环境的维护和恢复、生态与社会经济的和谐提供理论与实践指导。  相似文献   

9.
李丽  郝振纯  王加虎 《自然科学进展》2004,14(12):1452-1458
充分考虑水文要素和各种参数的空间变化是分布式水文模型的优势所在,信息技术的发展为它们的研究提供了更为方便易得的数据源,因此具有一定物理基础的分布式水文模型将成为水文学发展的必然方向.文中依据从DEM中提取的河网、水流路径长度和坡度等流域特征,建立了适合于黄河流域三门峡-小浪底区间水文过程模拟的分布式日模型,为进一步的次洪模拟和小浪底水库入库洪水预报系统研究提供了必要的参数和依据.  相似文献   

10.
根据已有产流机制的研究结果,提出了当土壤含水量大于栅格蓄水容量时会产生径流的栅格蓄水容量概念,以及通过栅格植被根系层深度和田间持水量计算流域内各点栅格蓄水容量的栅格蓄水容量计算方法,并在充分考虑流域内植被类型、土壤类型和土壤水分参数对流域蓄水容量分布影响的基础上,应用栅格垂向混合产流机制描述植被根系层的水量变化,从而避免了对复杂的土壤水运动过程的直接描述.甸子流域的应用结果表明,基于栅格垂向混合产流机制的分布式流域水文模型对多年连续序列模拟的效率系数达到0.744,年均径流深误差为1.18-mm,相对误差为2.18%.此模拟结果对于寒旱区的水文过程模拟来说是可以接受的.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

14.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

15.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

16.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

19.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
1 Rise of studies on climate change's effects on biodiversity
Until the 1980s, climate change and biodiversity were studied as two independent disciplines for more than a century. In 1992, the Ecological Society of America's annual report named climate change, biodiversity, and the sustainable ecological system as the three major global environmental issues of the twenty-first century [1].  相似文献   

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