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911.
兰州-民和盆地红古城组的建立及其地质学意义 总被引:7,自引:0,他引:7
兰州—民和盆地下白垩统地层,出露良好,厚度较大,自下而上可建立8个非正式的岩石地层单位(岩组)。红古城组位于下白垩统上部的第七岩组。该组以剖面连续、出露甚好、顶底清楚、厚度不大而与上、下地层显著不同,具独特的岩性、岩相特征。虽然岩性、岩相在横向上变化较快,但顶、底界线都具良好的标志层,在盆地内可以广泛追索和对比。该组岩石地层单位的正式建立,不仅便于区内地层的划分与对比,而且对盆内层序地层、岩相分析、构造演化的研究都具重要意义。 相似文献
912.
应用GIS技术进行油气资源评价的探讨 总被引:10,自引:0,他引:10
简要介绍了地理信息系统(GIS)概况,同时讨论了利用GIS进行油气评价的可能性及优越性,并利用此法辽河外围盆地进行凹陷评价,建立了辽河外围盆地地质信息系统,最后应用自组织神经网络对这些凹陷优选排队。 相似文献
913.
A new land surface parameterization scheme (ALSIS), with emphasis on soil moisture prediction, is described and validated with observations from HAPEX-MOBILHY and Cabauw. An important feature of the scheme is the inclusion of vertical heterogeneity of soil hydraulic parameters is modelling unsaturated flow. The simulated soil moisture for HAPEX site using a vertically homogeneous soil has a positive bias in the upper soil layers and a negative bias in the deep soil layers. Taking into account the soil vertical heterogeneity greatly eliminates this discrepancy and results in an excellent agreement between annual cycles of modelled and observed soil moisture profiles. The mean annual soil moisture in the top 1.6 m of soil increased from 394 mm for homogeneous case to 433 mm for the heterogeneous case, consistent with 435 mm observed. The improvement in soil moisture simulation resulted in an improved skill in predicting the mean and the diurnal cycles of surface fluxes for the intensive observational period (28 May–3 July). The simulated monthly averages of surface temperature and fluxes follow observations over the year, except for January when the model overestimates the latent heat flux due to its failure in simulating high rates of dew fall. The deviation of modelled monthly mean surface fluxes from observations are well within the estimated observational errors. The simulated mean daily surface temperature, and surface fluxes are generally consistent with observations, except for some times in the winter period. The modelled diurnal cycles of temperature and fluxes are in agreement with those observed. However, the model overestimates the night-time latent heat flux, especially during January. 相似文献
914.
Xu Liang Eric F. Wood Dennis P. Lettenmaier Dag Lohmann Aaron Boone Sam Chang Fei Chen Yongjiu Dai Carl Desborough Robert E. Dickinson Qingyun Duan Michael Ek Yeugeniy M. Gusev Florence Habets Parviz Irannejad Randy Koster Kenneth E. Mitchell Olga N. Nasonova Joel Noilhan John Schaake Adam Schlosser Yaping Shao Andrey B. Shmakin Diana Verseghy Kirsten Warrach Peter Wetzel Yongkang Xue Zong-Liang Yang Qing-cun Zeng 《Global and Planetary Change》1998,19(1-4)
The energy components of sixteen Soil-Vegetation Atmospheric Transfer (SVAT) schemes were analyzed and intercompared using 10 years of surface meteorological and radiative forcing data from the Red-Arkansas River basin in the Southern Great Plains of the United States. Comparisons of simulated surface energy fluxes among models showed that the net radiation and surface temperature generally had the best agreement among the schemes. On an average (annual and monthly) basis, the estimated latent heat fluxes agreed (to within approximate estimation errors) with the latent heat fluxes derived from a radiosonde-based atmospheric budget method for slightly more than half of the schemes. The sensible heat fluxes had larger differences among the schemes than did the latent heat fluxes, and the model-simulated ground heat fluxes had large variations among the schemes. The spatial patterns of the model-computed net radiation and surface temperature were generally similar among the schemes, and appear reasonable and consistent with observations of related variables, such as surface air temperature. The spatial mean patterns of latent and sensible heat fluxes were less similar than for net radiation, and the spatial patterns of the ground heat flux vary greatly among the 16 schemes. Generally, there is less similarity among the models in the temporal (interannual) variability of surface fluxes and temperature than there is in the mean fields, even for schemes with similar mean fields. 相似文献
915.
916.
含煤岩系沉积学和层序地层学研究现状和展望 总被引:35,自引:6,他引:29
在对含煤岩系沉积系研究历史进行回顾的基础上,论述了含煤岩系层序地层学方法以及海平面变化与聚煤作用的关系。注重强调分布广泛的厚煤层实际上是在基准面或海平面的抬升过程中堆积的,煤层底面代表海泛面。 相似文献
917.
SHAO Jing-an HUANG Xue-qin QU Ming WEI Chao-fu XIE De-ti 《中国地理科学(英文版)》2005,15(4):315-324
The old reservoir areas built in 1950s- 1970s left behind many socio-economic problems, because of the administrative backward migration and little migration fund, and all these problems would be tied to land. Based on interviewing with peasant households, combining land use survey and socio-economic statistical index, this paper analyzed land use change and its corresponding driving forces in Linshui reservoir area of Dahonghe Reservoir. Results showed that land use change in the reservoir area was mainly embodied on low-lying land submergence and migration requisition land. The former changed the land use patterns, and the latter mainly reconstructed original land property and made land over-fragmented. Cultivated land per capita was 0.041ha in this area, below the cordon of cultivated land per capita enacted by FAO. Currently, there were still 30.25% of peasant households being short of grain in trimester of one year, and there were 35.27% of people living under the poverty line. The conditions of eco-environmerit in Linshui Reservoir Area were worse, and healthy and sub-healthy eco-environment accounted for less proportion, composed of green belt around the reservoir area and paddy field ecosystem, and economic forest and orchard ecosystem, respectively. The stress of the reservoir project was macroscopic background to analyze the driving factors of land use change, and real underlying diving factor of the land use change in the area was the change of cultural landscape under the stress of reservoir project. The rapid increase of population was the key factor to induce the change of man-land relationship in the reservoir area, the low level of rural economy was the crucial factor to decide how migrants input for production, and the belief of migrants, influencing the land use patterns in a certain extent, was the inducing factor to keep land use stable. The low-lying submergence and infrastructure construction accompanied the reservoir project were leading factors driving land use change in the area, while changes in land use patterns, after the reservoir being built, were the responses of peasant households' behaviors to land use change. 相似文献
918.
绿洲生态环境质量评价指标体系研究--以张掖市绿洲为例 总被引:16,自引:1,他引:15
绿洲属于生态环境的极度脆弱区,同时绿洲生态系统又是一个复杂的系统,涉及自然与人文的诸多组元,因此定量评价其质量优劣状况具有重要意义也存在一定难度。在对我国西北内陆区域绿洲生态系统的性质和特点进行系统分析的基础上,根据整体性、实用性、稳定性、地域性、独立性原则,依据绿洲系统的压力-状态-响应模型,构建了适用于绿洲这一特殊景观类型的生态环境质量评价指标体系,并结合绿洲生态环境实际状况,应用层次分析法确定了各评价因子的权重和分级量化标准。在此基础上,以张掖市绿洲为例,对绿洲生态环境质量状况做了综合评价。 相似文献
919.
Relationships Between Tidal Prism and Throat Area of Tidal Inlets Along Yellow Sea and Bohai Sea Coasts 总被引:2,自引:0,他引:2
Zhang Renshun Wang Yaping P
rofessor Dept. of Geography Nanjing Normal University Nanjing
Lecturer Nanjing Normal University Nanjing 《中国海洋工程》1996,(2)
The relationship between P (spring tidal prism) and A (throat area below mean sea level) is statistically analysed in terms of 29 tidal inlets or bays along the Huanghai Sea (Yellow Sea) and Bohai Sea coasts. For 15 of these tidal inlets, the best regression equation is A(km2) = 0.845 />(km3)1.20. The analysis shows that C and n are little different from those in the P-A relationship for the inlets of the South China Sea and East China Sea coasts. It is noted that the relationship between P and A is unstable because of the difference in sediment abundance. The study shows that a united P-A relationship can be obtained for the tidal inlets of lagoon type and bay-drowned-valley type, not containing some half-circle shape bays which confront deep water. These half-circle bays do not belong to tidal inlets because they do not have enough sediment abundance and are fairly open. 相似文献
920.