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41.
本文詳細地介紹了武汉采用的交点相关法和十点相关法的理論基础和具体計算方法,并与Philtips和spcncer的相关法(PS法)及Yerg的六点相关法进行了比較。正如理論上所預期到的,武汉的实驗表明:交点法提供的参量最多,也最精确可靠,但計算量与PS法的差不多;十点法提供的参量与交点法的一样多,精确性不此PS法的低,然而計算量比PS法的少得多,与六点法的差不多。文中还討論了利用时移图上曲直线,以进一步提高十点法的精确性,以及在相关分析中采用結构函数和后效函数,以进一步簡化計算的可能性。本文还初步討論了各种相关分析法的誤差間題;并提出了相关函数值在时空上的預报方法,以及根据相关函数的預报值与实測值的对此等,判别在記录分析中有无反常現象,和甄別所求出的参量值是否可疑的方法。最后还特別指出了电离层混乱运动变化速度出現虛数值的可能性,并介紹了消除这种虛数值的方法。 相似文献
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提出了一种计算体积分方程的方法-改进型局域非线性迭代(MLNI),并用其对三维井间电磁场进行反演计算,该方法将井间大尺度散射体分为近场和远场区域两部分,它们的位置和尺寸均随场点位置的变化而改变,采用局域非线性近似计算近场区域的影响,将远场区域的影响作为外部激励源,采用迭代方法计算,该方法具有计算速度快,所需内存量少,收敛性好的优点,在反演中采用基于MLNI的非线性反演方法,利用这种方法可以将成像区域集中于一定范围内而不是整个三维空间,该反演方法由于考虑到了雅可比矩阵元素的非线性项,因而与传统的Born迭代反演方法相比更为精确和稳定,考虑到信息量和计算机内存的限制,第1次成像采用双重体元分割法进行较粗略的成像,然后缩小成像范围进行第2次较精确的成像,数值计算结果表明,MLNI是一种有效的计算井间大尺度异常体散射场的方法,将该方法用于反演过程能够得到较高分辨率的三维井间电导率图像。 相似文献
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本文利用武汉电离层观象台的高频多普勒台阵、TEC台阵和加密频高图等多种观测资料,分析了1987年9月23日发生在我国境内的日环食的电离层效应,简要地讨论了光食过程的电离层变化,着重研究了食后电离层扰动以及这种效应的高度演变和传播特征.结果表明:1.在不同高度上电离层的光化过程的弛豫时间不同,光食效应有明显的高度差异;2.食后出现了电离层行扰,这种扰动的特性随高度变化十分复杂,但不同高度上扰动的水平传播方向都指向日食中心带.这种扰动的激发源不在环食中心带内,它的激发可能与日食时大范围的大气冷却收缩所引起的低层大气运动的不稳定性有关. 相似文献
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本文给出了电离层中存在电离运动时的高频无线电波的多普勒频移的表达式,讨论了用高频多普勒阵研究电离层声重波扰动有关的若干电波传播问题。 相似文献
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Mapping shoreline changes along coastal regions is critically important in monitoring continuously rising sea surface heights due to climate change and frequent severe storms. Thus, it is especially important if the region has very high tidal ranges over very gentle tidal flats, which is a very vulnerable region. Although the various remote sensing platforms can be used to map shoreline changes, the spatial and temporal resolutions are not enough to obtain it for a short time. Accordingly, in this study we introduce the newly developed low altitude Helikite remote sensing platform to achieve much better resolutions of shorelines and a bathymetry. The Helikite stands for Helium balloon and Kite, which is a kind of aerial platform that uses the advantages of both a Helium balloon and a kite. Field experiments were conducted in the Jaebu Island, off the coast of the west Korean Peninsula in January 29, 2011. In order to extract shorelines from the consecutive images taken by the low altitude Helikite remote sensing platform, active contours without edges (ACWE) is used. Edges or boundaries exist primarily on places between one type of objective and the other. Since the hydrodynamic pressure has an effect everywhere, the locations of the waterlines can be the isobath lines. We could map several waterlines, which would enable us to complete a local bathymetry map ranges from 35 to 60 cm depth. The error resulting from applying ACWE algorithm to the imagery to determine the waterline is approximately less than 1 m. Therefore, it is very unique way to obtain such high resolutions of bathymetry with high accuracy for the regions of extremely high tidal ranges for a short time. 相似文献
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浅析高校国有资产管理存在的问题及解决的措施 总被引:4,自引:0,他引:4
高校国有资产管理是学校管理工作的重要组成部分,加强高校国有资产管理已经成了国家有关部门和高校管理人员普遍关注的问题,文章从高校国有资产管理中存在的问题入手,剖析其成因并提出解决的措施。 相似文献
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CHOI Jinyong JUN Kicheon CHOI Youngkwang CHO Kyoungho KWON Jae-Il PARK Jinsoon PARK Kwangsoon 《海洋学报(英文版)》2015,34(12):11-18
The Maenggol Channel and Uldolmok Strait, located on the south-west coast of Korea, have notably strong and complex currents due to tidal effects and to local geological factors. In these areas, electric power has been generated using strong tidal currents, the speed of which is more than 3 m/s during spring tides. The region also provides a shortcut for navigation. These tidal conditions are therefore sometimes useful, but may also cause terrible accidents or severe economic damage, in the absence of accurate information regarding ocean conditions. In April 2014, the passenger ferry MV Sewol capsized in the Maenggol Channel, with 295 passengers killed and 9 still missing. While this was unquestionably a man-made disaster, strong currents were one of the contributing causes. It was also difficult to conduct scuba diving rescue operations given strong current speeds, and accurate prediction of the time when the tide would turn was thus critically needed. In this research, we used the high-resolution coastal circulation forecasting system of KOOS (Korea Operational Oceanographic System) for analysis and simulation of strong tidal currents in such areas with many small islands, using measurements and modeling from this research area. For accurate prediction of tidal currents, small grid size-modeling was needed, and in this study, we identified a suitable grid size that offers efficiency as well as accuracy. 相似文献