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991.
《中华人民共和国地貌图集》的研究与编制   总被引:6,自引:4,他引:2  
Geomorphologic maps are one of the most fundamental materials of the natural environment. They have been widely used in scientific research,resource exploration and extraction,education and military affairs etc. An editorial committee was established in 2001 to collect materials for researching and compiling a set of new 1:1,000,000 geomorphologic atlas of China. A digital geomorphologic database was created with visual interpretation from Landsat TM/ETM imageries and SRTM-DEM etc. The atlas compiled from the database was finished. The main characteristics of the atlas are as follows:Firstly,Landsat TM/ETM imageries,published geomorphologic maps or sketches,geographical base maps,digital geological maps,and other thematic maps were collected,which were uniformly geometrically rectified,clipped into uniform sheets,and stored in the foundation database. Secondly,based on the legends of 15 sheets 1:1,000,000 maps published in the 1980s,a geomorphologic classification system was built by combining morphology and genesis types. The system comprised seven hierarchical layers:basic morphology,genesis,sub-genesis,morphology,micro-morphology,slope and aspect,material composition and lithology. These layers were stored in the database during visual image interpretation. About 2000 kinds of morpho-genesis and 300 kinds of morpho-structure were interpreted. Thirdly,the legend system was built,which included color,symbol bases and note bases etc.,compilation standards and procedures were developed,74 sheets of 1:1,000,000 covering all land and sea territories of China were compiled,the 1:1,000,000 geomorphologic atlas of the People’s Republic of China was finished and published. The atlas will fill the blanks in national basic scale thematic maps,and the geomorphologic database could be applied widely in many fields in the future.  相似文献   
992.
Isotope hydrograph separation (IHS) is a basic tool in applied hydrology. Its application has expanded to surface water and groundwater interaction, and eco-hydrological processes from runoff generation processes. This paper reviews the progress made in IHS for alpine catchments, with emphasis on its significance in reflecting the impact of global change on water resources. Also, the principle of IHS and its uncertainties are explained in detail. The mechanism of variation of stable isotopes in snow-melt water is discussed, and then methods are presented to improve the separation during snow-melt such as volume weighted average method (VWA), current melt-water method (CMW) and runoff-corrected event water approach (RunCE), with their advantages and disadvantages explained. New approaches may extend the applications of IHS, for example, large basin studies combined with GIS, and develop new theories of runoff generation combined with other parameters such as deuterium excess and DOC  相似文献   
993.
国家重点研发计划“黑碳的农业与生活源排放对东亚气候、空气质量的影响及其气候-健康效益评估”课题的中期研究进展可归纳如下:1)针对观测和实验平台,课题组进行了针对飞机气路的重新设计和改装,加装了用于航测的大气黑碳(BC)、气溶胶光学、细颗粒物粒径谱、颗粒物组分及气体组分来源示踪相关仪器,对飞机设备进行了质量控制,并设计了针对课题研究的新飞行方案。搭建了多套源排放模拟燃烧实验平台和监测系统。2)开展了基于飞机和飞艇的针对华北、华中、长三角及山东地区的黑碳垂直廓线观测。通过空地联合观测,捕捉到了华北和华中等地跨区域的黑碳大气传输过程,探讨了传输的机制。3)组织了多次农村能源消耗调查。基于室内实验初步研究了民用燃料(煤和生物质)排放气溶胶的数浓度和单颗粒气溶胶(包括黑碳)组成、混合状态、实时演化特性。初步构建了中国民用燃煤和生物质燃烧的多污染物(包括黑碳)1 km×1 km排放清单。4)建立了黑碳的光学特性和混合特性模型。采用在线大气化学耦合模式(WRF-Chem)针对黑碳气溶胶对气象要素和边界层发展的影响进行模拟,探讨了黑碳-边界层相互作用机制对地面臭氧浓度的影响,揭示了黑碳对空气污染加剧/减弱影响的物理和化学机制。改进了地球系统模式,为后期开展黑碳气溶胶辐射效应的研究打下了坚实的技术基础。5)在北京和成都市开展了黑碳浓度对居民中不同类人群的呼吸及循环系统死亡率的影响研究,开展了黑碳浓度对居民急诊就诊人数的影响研究,分析了黑碳的健康效应。  相似文献   
994.
广西县级气象影视服务发展对策研究   总被引:6,自引:4,他引:2  
在广西气象影视中心2009年6-9月开展的公众气象服务调研评估工作所获得的相关科学数据的基础上,对广西县级气象影视发展状况和影响因素以及集约化效益进行科学分析,提出了进一步推动集约化发展、多级气象影视部门合作共赢的思路。  相似文献   
995.
环渤海虚拟地震台网建设   总被引:1,自引:1,他引:0  
介绍环渤海虚拟地震台网的建设意图和内容,以及该台网建成后发挥的重要作用.环渤海虚拟地震台网的建设,可提高环渤海地区的地震监测能力,为研究海洋地震提供基础资料,以满足防震减灾事业的需要.  相似文献   
996.
A technique to extract real modes from the identifi ed complex modes is presented in this paper, which enables the normalized real mode shapes, modal masses, and full or reduced mass and stiffness matrices to be obtained. The theoretical derivation of the method is provided in detail. An 11-DOF vibration system is used to validate the algorithm, and to analyze the effects of the number of modes utilized and measurement DOFs on the extraction results. Finally, the method is used to extract real modes from bo...  相似文献   
997.
Probabilistic analysis of underground rock excavations is performed using response surface method and SORM, in which the quadratic polynomial with cross terms is used to approximate the implicit limit state surface at the design point. The response surface is found using an iterative algorithm and the probability of failure is evaluated using the first-order and the second-order reliability method (FORM/SORM). Independent standard normal variables in U-space are chosen as basic random variables and transformed into correlated non-normal variables in the original space of random variables for constructing the response surface. The proposed method is first illustrated for a circular tunnel with analytical solutions considering Mohr–Coulomb (M–C) and Hoek–Brown (H–B) yield criteria separately. The failure probability with respect to the plastic zone criterion and the tunnel convergence criterion are estimated from FORM/SORM and compared to those obtained from Monte Carlo Simulations. The results show that the support pressure has great influence on the failure probability of the two failure modes. For the M–C model, the hypothesis of uncorrelated friction angle and cohesion will generate higher non-performance probability in comparison to the case of negatively correlated shear strength parameters. Reliability analyses involving non-normal distributions are also investigated. Finally, an example of a horseshoe-shaped highway tunnel is presented to illustrate the feasibility and validity of the proposed method for practical applications where numerical procedures are needed to calculate the performance function values.  相似文献   
998.
There is a wide distribution of thick evaporites in the He21 and He1 Members of the Wuyang Sag, Southern North China Basin. Based on drilling data, previous researchers have analyzed the formation mechanism of evaporites in Wuyang Sag, and considered that their origination stems from the insufficient provenance and dry climate of the area. However, other researchers have suggested that the Qinling-Dabie Mountains, on the southern part of Wuyang Sag, acted as a stable source material throughout the deposition period of the sag. These contrasting hypotheses indicate that further investigation is needed to clearly identify the evaporite genesis mechanism in Wuyang Sag. Using both seismic and geologic data, this paper analyzes the impact of the uplift structure of the Wuyan Sag area on evaporite formation. This analysis is based on restoration of the southern boundary of the sag in the deposition period with respect to the largest strike-slip fault. Taking the erosion of the lower Tertiary strata at the southern boundary of the sag (greatest tectonic activity) as the starting point of this study, and the movement of the NW strike-slip fault at the eastern part of the sag, the following conclusions were drawn: (1) The end stage of deposition of the He22 Member of the Hetaoyuan Formation was an important period in the base level transition for the Wuyang Sag. During the depositional period from the He3 Member to the He22 Member, the sag gradually expanded as the base level was rising. In the depositional period from the He21 Member to the He1 Member, the sag gradually shrank, and the base level was lowered due to the influence of structural uplift. In the meantime, inside the sag, the left-lateral strike-slip fault at the basement became active again and caused the eastern area of the strike-slip fault to be uplifted in the depositional period from the He21 Member to deposition of the Liaozhuang Formation. (2) The structure uplift during the depositional period from the He3 Member to the He22 Member blocked part of the provenance to infill the Wuyang Sag. Therefore, this activity resulted the sag becoming closed or semi-closed, leading to the deposition of evaporites.  相似文献   
999.
本文对大同市粮食产量与气候因子进行统计分析,把作物各生育时段的降水量与气象产量的关系进行回归分析,建立相关方程,从而得出由于干旱造成的产量损失评估模型。  相似文献   
1000.
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