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81.
本区地槽型煤田,主要是下寒武统牛蹄塘组,由一套浅海相碳质板岩为主组成的含钒石煤岩系,与下伏地层呈整合关系。地台型煤田有下石炭统测水煤系和上二叠统斗岭煤系,它们是以一套海陆交互相的细碎屑岩为主,夹菱铁矿或黄铁矿结核及煤组成,与下伏地层呈整合关系。其中斗岭煤系的煤层分布广,煤层及煤质较好,是本区找煤的对象。地洼型煤田,为上三叠—下侏罗统煤系,呈零星小块分布,是一套以陆相,杂色粗碎屑岩为主,夹泥岩及煤组成,与下伏地层呈不整合关系。主要发育在资兴市和宜章县一带,找煤条件次于斗岭煤系。 相似文献
82.
环境场作用与西南低涡移动的初步分析 总被引:4,自引:0,他引:4
本文将西南低涡视为迭加在环境场上的一个扰动,把考虑环境场和非绝热作用下的次天气尺度扰动方程组写在一个简单斜压两层模式上,根据西南低涡的特点对方程组作一些近似处理,导得了反映低层(700hPa)西南低涡移动特征的移矢诊断方程。由此分析了影响西南低涡移动的主要因子,得出了一些定性结果。最后,利用移矢诊断方程作了低涡移动的实例计算分析,其结果与实况比较一致。 相似文献
83.
84.
P. Fabbri 《Mathematical Geology》2001,33(6):745-760
In the geothermal Euganean area (Veneto region, NE Italy) water temperatures range from 60 to 86°C. The aquifer considered is rocky and the production wells in this study have a depth ranging from 300 to 500 m. For exploitation purposes, it is important to identify zones with a high probability that the temperature is more than 80°C and zones with a high probability that the temperature is less than 70°C. First, variographic analysis was conducted from 186 temperature data of thermal ground waters. This analysis gave results that are consistent with the main regional tectonic structure, the NW-SE trending Schio-Vicenza fault system. Then indicator variograms of the second, fifth, and eighth decile were compared to identify the spatial continuity at different thresholds. The unacceptability of a multigaussian hypothesis of the random function and the necessity to know the cumulative distribution function in any location, suggested the use of a nonparametric geostatistical procedure such as indicator kriging. Thus, indicator variograms at the cutoffs of 65, 70, 73, 75, 78, 80, 82, and 84°C were analyzed, fitted, and used during the indicator kriging procedure. Finally, probability maps were derived from postprocessing indicator kriging results. These maps identified scarcely exploited areas with a high probability of the temperature being higher than 80°C, between 70 and 80°C and areas with high probability of the temperature being below 70°C. 相似文献
85.
Ionosphere-magnetosphere disturbances at high latitudes, e.g. magnetic substorms, are accompanied by energetic particle precipitation and strong variations of the ionospheric electric fields and currents. These might reasonably be expected to modify the local atmospheric electric circuit. We have analysed air-earth vertical currents (AECs) measured by a long wire antenna at Esrange, northern Sweden during 35 geomagnetic substorms. Using superposed epoch analysis we compare the air-earth current variations during the 3 h before and after the time of the magnetic X-component minimum with those for corresponding local times on 35 days without substorms. After elimination of the average daily variation we can conclude that the effect of substorms on AEC is small but distinguishable. It is speculated that the AEC increases observed during about 2 h prior to the geomagnetic X-component minimum, are due to enhancement of the ionospheric electric field. During the subsequent 2 h of the substorm recovery phase, the difference between substorm and quiet atmospheric currents decreases. The amplitude of this substorm variation of AEC is estimated to be less than 50% of the amplitude of the diurnal variation in AEC during the same time interval. The statistical significance of this result was confirmed using the Van der Waerden X-test. This method was further used to show that the average air-earth current and its fluctuations increase during late expansion and early recovery phases of substorms. 相似文献
86.
The most important features of the quasi-electrostatic fields (QSFs) and currents, generated in the region between a thunderstorm (TS) and the ionosphere between lightning discharges, are theoretically investigated. They depend on different factors having large variability, related to the TS and to the atmospheric conductivity. These features are studied in order to understand better the conditions when QSFs cause modifications of the parameters and chemical balance in the lower ionosphere over TSs due to electron heating, as well as the generation of red sprites. For this purpose, an analytical model based on Maxwell's equations under conditions of curl-free electric fields is presented. The temporal and spatial behaviour of the QSFs is studied as a function of the parameters of lightning discharges and of atmospheric conductivity. The dependence of the QSF, mainly its peak values, on the charge moment change, the discharge time, and the horizontal extent of the discharged region, on the one hand, and of the conductivity profile, on the other, is studied. It is shown that the profile of the QSF time peak changes its scale height at the altitudes where the relaxation time becomes equal to the discharge time, and where the conductivity scale height is diminished; below these altitudes the peak QSFs decrease with time much slower than above them. Also, the QSF peak increases almost linearly with the charge height and depends little on the size of the discharged region. The total Maxwell and conduction currents, which flow from the TS to the ionosphere, are also studied. The peak current is proportional to the charge moment change, and actually does not depend on the frequency of lightning discharges. 相似文献
87.
新疆煤层气资源赋存特征及开发潜力分析 总被引:5,自引:0,他引:5
通过对新疆主要煤田的煤炭资源分布特征,煤变质特征及构造特征分析,探讨新疆的煤层气资源赋存特征,对新疆主要煤田煤层气资源的勘探开发潜力进行初步评价,新疆的煤层气基本属于少生中储型,虽然单位含气量较低,但煤炭资源非常丰富,且相对集中,煤气具有较大的勘探开发潜力。 相似文献
88.
LIU WenbaoXIA Zongguo DENG Min 《地球空间信息科学学报》2001,4(4):37-42
1 IntroductionTherepresentationofspatialobjectsisoneofthekeyissuesincurrentresearchonthespatialdatabasetheoryofGIS (BurroughandMcDonnell,1 998) .Spatialobjectsinnatureareclassifiedastwokinds:objectswithdistinctiveboundariesandob jectswithtransitionalorfuzzy… 相似文献
89.
A numerical simulation model is presented in this paper,which comprises the processes of crop growth,soil organic carbon decomposition,and methane emissions in agroecosystems.Simulation results show that the model can simulate the main process of methane emissions well,and the correlation coefficient between the simulated values and observed data is 0.79 with 239 samples,which passed a significance test of 0.01.The average error of methane emission simulation in whole growth period is about 15%.Numerical analysis of the model indicates that the average temperature during rice growth period has much impacts on methane emissions,and the basic trend of interannual methane emissions is similar to that of average temperature.The amount of methane emissions reduces about 34.93%,when the fertilizer is used instead of manure in single rice paddy. 相似文献
90.
任意形状重磁异常三度体人机联作反演 总被引:13,自引:2,他引:13
作者在文中介绍了一种基于三角形多面体模型的重磁三维反演技术,其特点是既可通过和自动迭代方式来改变反演模型,又可通过过人机交互方式来改变模型,该技术具有较高的实用性。 相似文献