苏北大陆科学钻探靶区重磁异常反演解释   总被引：6，自引：2，他引：6       下载免费PDF全文

余钦范  姚长利  孟小红  郭友钊 《地球物理学报》2001,44(6):825-832

对江苏东海县毛北地区重、磁观测异常进行了处理和特征分析,并根据科学钻探主要目标体榴辉岩与其围岩有达0.9×103kg/m3的明显密度差,进行了等效密度反演成像与综合地震约束反演计算.给出了该地区重力异常模型,可作为综合地质与地球物理研究的一个基础.  相似文献   

关于地球科学人才培养的实践与思考   总被引：2，自引：0，他引：2  

王德滋  赵连泽 《江苏地质》2001,25(3):129-133

世纪之交的我国地质行业和地质学人才培养遇到了前所未有的困难,而资源、环境与灾害已成为新世纪人类社会发展面临的严峻问题.面对挑战和机遇,南京大学地球科学系以邓小平教育理论为指导,以创建“地质学“国家理科人才培养基地为契机,在教学改革的实践中探索并建立了基础型和应用型两类地质学人才的培养体系,依托本系雄厚的教学科研基础和师资力量,建成“三三三“培养模式和全新的课程体系,改革教学内容和方法、手段,提高学生综合素质和创新能力,七年来改革成果丰硕.2000年以来,在教育部世行贷款重点教改项目支持下,结合地学类学科在新世纪的发展趋势,正在努力探索按“大地学“口径培养人才的模式,创建培养具有大理科基础、大地学特色的地球科学人才的实施方案,为我国国土资源的合理开发利用、灾害防治和环境保护等的迫切需要培养新一代地学人才.  相似文献   

Estimation of Hourly and Daily Global Solar Radiation at Clear Days Using an Approach Based on Modified Version of Gaussian Distribution     

S. M. El shazly 《大气科学进展》1996,13(3):349-358

The performance of two models,Jam and Baig,based on the modified version of Gaussian distribution function in estimating the daily total of global solar radiation and its distribution through the hours of the day from sunrise to sunset al any clear day is evaluated with our own measured data in the period from June 1992 to May 1993 in Qena Egypt The results show a high relative deviation of calculated values from measured ones,especially for Jain model,in the most hours of the day,except for those near to local noon.This misfit behavior is quite obvious in the early morning and late afternoon A new approach has been proposed in this paper to estimate the daily and hourly global solar radiation This model performs with very high accuracy on the recorded data in our region.The validity of this approach was verified with new measurements in some clear days in June and August 1994.The resultant very low relative deviation of the calculated values of global solar radiation from the measured ones confirms the  相似文献   

地表MPBL系统及两个尺度的全球变化模型   总被引：2，自引：0，他引：2  

孙根年 《地球科学进展》1998,13(5):481-487

提出了地表MPBL系统的概念,并认为它是一个开放性的复杂巨系统;在此基础上探讨了地表MPBL系统内的三大类复合系统及其自组织问题,给出了一个较完整的地表MPBL系统结构模式,可作为认识各种时间尺度全球环境变化的研究纲领;为了适应10³～10⁵a、10¹～10²a两个尺度全球环境变化研究需要,也对这两个尺度全球环境变化模型进行了一些改进,使其更符合地表MPBL系统概念。  相似文献   

Time-Variations of D-Region Electron Densities, and Comparisons With Model Computations     

Suman Ganguly  John Zinn 《Studia Geophysica et Geodaetica》1998,42(4):500-510

An extensive series of incoherent scatter studies of the ionospheric D-region was carried out at the Arecibo radar facility during 1978 and 1979. They included several full-day sequences of electron density measurements over a range of altitudes, and also included a sequence during the serendipitous occurrence of a large solar flare. For the solar flare event simultaneous data on solar X-ray fluxes in several wavelength bands were available from the GOES-2 and ISEE-3 satellites. In the course of development of a large ionospheric computer model at Los Alamos we have used the solar flare data as a reality check. The solar X-ray flux data were used as inputs for computing ionization rates. The model computer includes 999 chemical reactions, and also includes diffusion and transport processes. In the course of the flare studies we used the data comparisons to adjust the values of three chemical rate coefficients that were poorly known. With those adjustments the model computations fitted the data quite well. Subsequent to the flare analysis we have been using the same model with some minor updates to compute the expected diurnal variations of the ambient D-region under conditions chosen to match those existing at the times of the incoherent scatter measurements. Comparisons of the computations and the data will be shown, and the relative importance of the several separate ionization processes will be discussed. We also compare model results with experimental data on concentrations of NO.  相似文献   

基于HMM双重模型的伽马能谱漂移模拟     

黄洪全  方方  龚迪琛  丁卫撑 《物探与化探》2010,34(4)

结合放射性测量中的能谱统计特性及漂移特点,提出了采用hidden Markov models对能谱漂移进行模拟的双重模型方法。采用Gaussian mixture model对能谱的短时瞬态特性进行描述,转化为参数化模型;采用HMM状态转移对能谱测量中的能谱漂移条件进行模拟,实现Gaussian mixture model的参数调整。实例表明,该方法可以灵活地调整参数以满足能谱漂移模拟的多样性要求,是一种性能良好的参数化模拟方法。  相似文献   

The use of 137Cs as a tracer in an erosion study in south limburg (the Netherlands) and the influence of chernobyl fallout     

A. P. J. De Roo 《水文研究》1991,5(2):215-227

The ¹³⁷Cs radioactivity of soils was used as a tracer of soil erosion in a catchment in the Netherlands: 143 samples were analysed to map the ¹³⁷Cs redistribution using geostatistical interpolation methods. Caesium-137 activities on grassland are significantly higher than on arable land. Also, ¹³⁷Cs activities on waning slopes are higher and activities on steep slopes are lower. The soil erosion estimates, derived from the ¹³⁷Cs data, are used to validate the USLE erosion model. The recent Chernobyl nuclear accident also contributed to the ¹³⁷Cs activity. However, the Chernobyl input of ¹³⁷Cs, with a constant ratio of 1.765:1 to ¹³⁴Cs, cannot be used as a tracer of soil erosion. Because of the rapid decay of ¹³⁴Cs, we will not be possible to separate the sources of ¹³⁷Cs in the near future in areas significantly influenced by Chernobyl fallout and in these areas ¹³⁷Cs can no longer be used as a soil erosion tracer.  相似文献   

Uncertainty in structural interpretation: Lessons to be learnt     

《Journal of Structural Geology》2015

Uncertainty in the interpretation of geological data is an inherent element of geology. Datasets from different sources: remotely sensed seismic imagery, field data and borehole data, are often combined and interpreted to create a geological model of the sub-surface. The data have limited resolution and spatial distribution that results in uncertainty in the interpretation of the data and in the subsequent geological model(s) created. Methods to determine the extent of interpretational uncertainty of a dataset, how to capture and express that uncertainty, and consideration of uncertainties in terms of risk have been investigated. Here I review the work that has taken place and discuss best practice in accounting for uncertainties in structural interpretation workflows. Barriers to best practice are reflected on, including the use of software packages for interpretation. Experimental evidence suggests that minimising interpretation error through the use of geological reasoning and rules can help decrease interpretation uncertainty; through identification of inadmissible interpretations and in highlighting areas of uncertainty. Understanding expert thought processes and reasoning, including the use of visuospatial skills, during interpretation may aid in the identification of uncertainties, and in the education of new geoscientists.  相似文献   

Simulation of Precipitation in Monsoon Regions of China by CMIP3 Models   总被引：1，自引：0，他引：1       下载免费PDF全文

TU Kai  YAN Zhong-Wei  ZHANG Xue-Bin  DONG Wen-Jie 《大气和海洋科学快报》2009,2(4):194-200

The output of 25 models used in the Coupled Model Intercomparison Project phase 3 （CMIP3） were evaluated, with a focus on summer precipitation in eastern China for the last 40 years of the 20th century. Most models failed to reproduce rainfall associated with the East Asian summer monsoon （EASM）, and hence the seasonal cycle in eastern China, but provided reasonable results in Southwest （SW） and Northeast China （NE）. The simulations produced reasonable results for the Yangtze-Huai （YH） Basin area, although the Meiyu phenomenon was underestimated in general. One typical regional phenomenon, a seasonal northward shift in the rain belt from early to late summer, was completely missed by most models. The long-term climate trends in rainfall over eastern China were largely underestimated, and the observed geographical pattern of rainfall changes was not reproduced by most models. Precipitation extremes were evaluated via parameters of fitted GEV （Generalized Ex- treme Values） distributions. The annual extremes were grossly underestimated in the monsoon-dominated YH and SW regions, but reasonable values were calculated for the North China （NC） and NE regions. These results suggest a general failure to capture the dynamics of the EASM in current coupled climate models. Nonetheless, models with higher resolution tend to reproduce larger decadal trends and annual extremes of precipitation in the regions studied.  相似文献   

油气资源预测统计模型及其应用   总被引：5，自引：3，他引：2       下载免费PDF全文

刘晓冬  徐景祯  杨勉 《地质科学》2004,39(2):245-250

松辽盆地北部的油气勘探程度虽然较高,但仍然有一些尚未发现的油气资源。本文在对预测油气资源的分形分布模型和截断帕雷托(TSP)分布模型两种统计模型进行系统研究的基础上,结合油气藏地质规律,通过预测该区未发现的油(气)田数量及其储量规模分布,认为方法可行,结果供参考,并待实践进一步验证。得出主要结论是:分形分布模型是一种预测油气田数量和储量(资源量)的可靠方法,在勘探程度较高的盆地或区带应用效果较好,而在勘探新区应用则有一定难度;截断帕雷托分布模型相对于分形分布模型不很完善,但应用该模型进行油气资源分布预测受具体盆地地质条件的影响较小,具有应用价值。  相似文献