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991.
ABSTRACT In this study, three representative concentration pathways (RCPs) and 15 general circulation models of the Coupled Model Intercomparison Project Phase 5 were used to assess the behaviour of precipitation (P) and surface air temperature (SAT) over part of the Songhua River Basin. The Water Evaluation and Planning (WEAP) model linked with SAT and P was used for monthly simulation of streamflow to assess the influence of land use/land cover and climate change on the streamflow. The results suggest that, under RCP2.6, RCP4.5 and RCP8.5, the SAT over the study area may increase in the 21st century by 1.12, 2.44 and 5.82°C, respectively. Moreover, by the middle of the 21st century, streamflow in the basin may have decreased by 19%. The decrease in streamflow may be due to changed land use conditions and water withdrawal, having critical implications for management and future planning of water resources in the basin. 相似文献
992.
把消除掉气压、固体潮效应后的西影井水位值与临潼——长安断裂带上的垂直形变值进行相关分析,发现二者有一定的相关性。可以看出,西影深井水位变化在某种程度上反映着井位附近的断层活动。最后作者对其形成原因进行了粗浅的分析。 相似文献
993.
各种地貌学、沉积学等证据揭示了青海湖流域在全新世大暖期是一个温暖湿润的环境,特别是距今6000~7200a.B.P.的稳定暖湿期,湖水位远高于现代.利用内陆湖泊的水热平衡原理,构造了青海湖古水量平衡计算模型.计算结果表明,在全新世稳定暖湿期,流域内的降水量、蒸发量及径流量分别比现代高32.0%、14.0%及67.0%. 相似文献
994.
995.
996.
总结了浮标水位仪的频率特性、水井含水层系统的频率特性,及联合考虑以上两者后的频率特性,从而找出水震波的振幅与水位仪及水井含水层各参数之间的定量关系──系统响应的放大系数。 相似文献
997.
998.
G. Pickup 《地球表面变化过程与地形》1980,5(1):61-75
A computer-based study of the impact of the proposed Wabo hydroelectric scheme on the Purari River, Papua New Guinea was carried out. The HEC-6 model, Scour and Deposition in Rivers and Reservoirs developed by the Hydrologic Engineering Centre was used to simulate the effect of the dam on sediment transport and erosion in the lower Purari. Two runs with the model were carried out. The first one was used to establish baseline conditions and the second modelled dam impact. Before the study was carried out, data had to be collected on channel geometry, sediment input, river bed material size composition and hydraulic conditions in the river. Supplementary models also had to be developed to fill in gaps in runoff records and to describe flow in the river during power generation. Results of the investigation indicate that limited erosion will occur because of bed-armouring and the river will adjust towards a new equilibrium condition quite rapidly. The sediment output of the river into the Purari delta will change, load in the clay, silt and sand/gravel fractions decreasing by 22, 53 and 78 per cent respectively. 相似文献
999.
Gary E. Thomas Charles A. Barth Elaine R. Hansen Charles W. Hord George M. Lawrence George H. Mount Gary J. Rottman David W. Rusch A. Ian Stewart Ronald J. Thomas Julius London Paul L. Bailey Paul J. Crutzen Robert E. Dickinson John C. Gille Shaw C. Liu John F. Noxon Crofton B. Farmer 《Pure and Applied Geophysics》1980,118(1):591-615
The 1981–82 Solar Mesosphere Explorer (SME) mission is described. The SME experiment will provide a comprehensive study of mesospheric ozone and the processes which form and destroy it. Five instruments will be carried on the spinning spacecraft to measure the ozone density and its altitude distribution from 30 to 80 km, monitor the incoming solar ultraviolet radiation, and measure other atmospheric constituent which affect ozone. The polar-orbiting spacecraft will be placed into a 3pm-3 am Sun-synchronous orbit. The atmospheric measurements will scan the Earth's limb and measure: (1) the mesospheric and stratospheric ozone density distribution by inversion of Rayleigh-scattered ultraviolet limb radiance, and the thermal emission from ozone at 9.6 m; (2) the water vapor density distribution by inversion of thermal emission at 6.3 m; (3) the ozone photolysis rate by inversion of the O2(1g) 1.27 m limb radiance; (4) the temperature profile by a combination of narrow-band and wide-band measurements of the 15 m thermal emission by CO2; and, (5) theNO2 density distribution by inversion of Rayleighscattered limb radiance at 0.439 m. The solar ultraviolet monitor will measure both the 0.2–0.31 m spectral region and the Lyman-alpha (0.1216 m) contribution to the solar irradiance. This combination of measurements will provide a rigorous test of the photochemical equilibrium theory of the mesospheric oxygen-hydrogen system, will determine what changes occur in the ozone distribution as a result of changes in the incoming solar radiation, and will detect changes that may occur as a result of meteorological disturbances. 相似文献
1000.
R. M. Stesky 《Pure and Applied Geophysics》1978,116(4-5):690-704
This paper reviews many of the mechanical properties of faulted and jointed rock under pressure and temperature and in the presence of water. At low effective confining pressures (below about 1 kilobar), the friction strength is quite variable and depends on the frictional resistance between gouge particles or asperities and on the dilatancy of the fault. At higher pressures the friction strength is nearly independent of mineralogy, temperature, and rate, at least for rocks whose friction strength is less than the failure strength. Water tends to slightly weaken the fault. The type of sliding motion, whether stick-slip or stable sliding, is much more affected by environmental and mineralogical factors. In general, stick-slip is dominant at high pressures and low temperatures, in the presence of strong minerals such as quartz and feldspar, in the absence of gouge, for lower surface roughness, and perhaps in the presence of water. The microscopic deformation mechanisms are poorly understood. At low temperatures, cataclasis dominates in rocks containing mostly quartz or feldspar, and plastic deformation in rocks containing mostly calcite or platy silicates. At high temperature most minerals deform plastically, producing a greater temperature-and rate-dependence of the friction strength. Glass has been found in some sliding surfaces in sandstone. 相似文献