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991.
本软件采用Foxpro2.5新一代数据库管理系统编写,主要用于遥测地震台网的设备管理及常规系统标定参数的计算,并已在1995年系统标定中得到了实践检验。 相似文献
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Using output made with the National Center for Atmospheric Research (NCAR) Community Climate Model Version 1 (CCM1), the
characteristics of blocking events over the Northern Hemisphere in a ten-year present day control simulation with a CO2 concentration of 330 ppm were compared to those in a previously analyzed observational three-year climatology. The characteristics
of blocking events in a double present-day CO2 concentration simulation were then compared to those in the control simulation in order to evaluate how these characteristics
might change in an increased CO2 atmosphere. The results demonstrated that in the Northern Hemisphere the CCM1 correctly simulated many characteristics of
blocking events such as average annual number of occurrences, annual variations is size and intensity, and preferred formation
regions. A more detailed analysis (i.e., by region and season) revealed some differences between the CCM1 and observed blocking
events for characteristics such as mean frequency of occurrence, intensity, size and duration. In addition, the model failed
to capture adequately the occurrence of blocking events over the western Asian continent. A comparison of the double CO2 concentration run to the control showed that, in general, blocking events were more persistent and weaker, but of similar
size in the increased CO2 atmosphere. Also, some statistically significant regional and seasonally dependent changes were found in the frequency of
occurrence, duration, and intensity. Finally, a correlation between block size and intensity, significant at the 99% confidence
level, was found in each climatology. This result is similar to a correlation found in the analysis of observations.
Received: 8 May 1995 / Accepted: 20 September 1996 相似文献
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利用一个二维大气模式,研究粗糙冷岛宽度与布局对局地气候的影响问题。结果表明:粗糙冷岛激发的局地环流随其宽度的变化表现出3种流型-单环流型,双上升单下沉型,双环流型。存在40-50km左右的临界宽度dc,当粗糙冷岛宽度d〈dc时,粗糙冷岛激发的局地环流随d的增加而明显增强;而d〉dc时,局地环流随d的增国变化不大,甚至趋向准定常。 相似文献
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A.I. Olayinka 《Journal of African Earth Sciences》1997,24(4):635-647
The magnitude of errors in the determination of depth to bedrock from Wenner and Schlumberger resistivity sounding curves, caused by the non-identification of a suppressed layer, has been investigated. The principal objective is to evaluate how the layer thicknesses and resistivities affect the accuracy of depth estimates. In the computations, the intermediate layer in a 3-layer model, in which the resistivity increases with depth, is removed and the 2-layer sounding curve that is electrically equivalent to the 3-layer curve is generated. The results indicate that there is a possibility for large depth underestimations when the resistivity contrast between layers 1 and 2 is very large. This is manifested in a steeply rising terminal branch on the sounding curve. There is a slight decrease in the depth underestimation as the resistivity contrast between layers 2 and 3 increases. Conversely, if the intermediate layer is fairly thick and the resistivity contrasts are not too large, the best-fit 2-layer curve shows large deviations from the 3-layer curve. In such cases, the intermediate layer can be identified, resulting in reliable depth estimates. A field example from Nigeria is presented in which the sounding data has been interpreted so as to account for a prebasement layer of intermediate resistivity, indicative of a fractured granite. 相似文献
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Y. L. Voitsekhovsky A. K. Shpachenko V. I. Skiba 《International Journal of Earth Sciences》1997,86(3):531-538
Textures of tinguaite dykes cutting the alkaline Khibiny massif in the Kola Peninsula, Russia, are described. They are characterized by a combination of a fractal microfracture network dividing rock into pencil-like cells and of a concentric rhythmical zonation in almost all of them. The latter is formed by interchange of volatile-enriched and volatile-depleted mineral zones. The location of the textures only where dykes contact host khibinites appears to point out the contraction nature of the microfracture network. The cooling time calculated agrees well with this hypothesis. The zonation appears to have arisen through autometamorphic processes with two main competing factors, namely (a) overall cooling of the system and (b) periodic depletion of it in some elements, mainly Na and K. Another mechanism which may be applied to explain the zonation is the known Marangoni Instability effect at the early stage of evolution of the volatile-saturated phonolite melt. Thus, tinguaite textures are caused by nonspecific influences external to the system and may be regarded as an example of self-organization in nature. 相似文献