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961.
本文应用统计方法,首先探讨南方涛动指数与西北太平洋副热带高压的联系,然后分析赤道和热带太平洋区域海温对南方涛动的响应情况,同时分析南方涛动响应区域的海温与当时及滞后的西北太平洋副热带高压的联系,从中探讨南方涛动、厄尔尼诺海温异常及西北太平洋副热带高压之间的一种可能的相互作用机制。 相似文献
962.
Christopher Packham Keith L. Thompson Almudena Zurita Johan H. Knapen Ian Smail Robert Greimel Daniel F. M. Folha Chris Benn rew Humphrey Rene Rutten David Ciardi Matthieu Bec Richard Bingham Simon Craig Kevin Dee Derek Ives Paul Jolley Peter Moore Marti Pi i Puig Simon Rees Gordon Talbot Sue Worswick 《Monthly notices of the Royal Astronomical Society》2003,345(2):395-405
963.
Dehydration melting of solid amphibolite at 2.0 GPa: Effects of time and temperature 总被引:3,自引:0,他引:3
ZHOU Wenge XIE Hongsen LIU Yonggang ZHENG Xiaogang ZHAO Zhidan & ZHOU Hui . Laboratory of Material in the Earth’s Interior Institute of Geochemistry Chinese Academy of Sciences Guiyang China . Department of Geology China University of Geosciences Beijing China . Department of Geology Peking University Beijing China 《中国科学D辑(英文版)》2005,48(8):1120-1133
The dehydration melting of the natural rock at high pressure is important to investigating the magma formation in the earth’s interior. Since the 1970s, a lot of geological scientists have paid more atten- tion to the dehydration melting of the natural rock[1―5]. Previous experiments of dehydration melting and observations of fieldwork argued that the dehy- dration melting of the rock was probably the most important fashion for the melting of the lower crust rock[6―12]. The genesis of most … 相似文献
964.
Koshi Nishimura Tatsuhiko Kawamoto Tetsuo Kobayashi Takeshi Sugimoto Shigeru Yamashita 《Bulletin of Volcanology》2005,67(7):648-662
Dacitic magma, a mixture of high-temperature (T) aphyric magma and low-T crystal-rich magma, was erupted during the 1991–1995 Mount Unzen eruptive cycle. Here, the crystallization processes of the low-T magma were examined on the basis of melt inclusion analysis and phase relationships. Variation in water content of the melt inclusions (5.1–7.2 wt% H2O) reflected the degassing history of the low-T magma ascending from deeper levels (250 MPa) to a shallow magma chamber (140 MPa). The ascent rate of the low-T magma decreased markedly towards the emplacement level as crystal content increased. Cooling of magma as well as degassing-induced undercooling drove crystallization. With the decreasing ascent rate, degassing-induced undercooling decreased in importance, and cooling became more instrumental in crystallization, causing local and rapid crystallization along the margin of the magma body. Some crystals contain scores of melt inclusions, whereas there are some crystals without any inclusions. This heterogeneous distribution suggests the variation in the crystallization rate within the magma body; it also suggests that cooling was dominant cause for melt entrapment. Numerical calculations of the cooling magma body suggest that cooling caused rapid crystal growth and enhanced melt entrapment once the magma became a crystal-rich mush with evolved interstitial melt. The rhyolitic composition of melt inclusions is consistent with this model.Editorial responsibility: H Shinohara 相似文献
965.
采用双压力室三轴仪对粉煤灰试样进行了单线法湿陷试验,研究了在静水压力作用以及在不同应力状态和应力水平下粉煤灰湿陷变形的规律,得出了粉煤灰湿陷变形的经验计算公式.提出了计算粉煤灰地基湿陷变形的"全应变曲线"增量有限元法.基于本文的试验结果,对一个粉煤灰地基的湿陷变形进行了有限元计算. 相似文献
966.
Using a Love number formalism, the elastic deformations of the mantle and the mass redistribution gravitational potential within the Earth induced by the fluid pressure acting at the core–mantle boundary (CMB) are computed. This pressure field changes at a decadal time scale and may be estimated from observations of the surface magnetic field and its secular variation. First, using a spherical harmonic expansion, the poloidal and toroidal part of the fluid velocity field at the CMB for the last 40 years is computed, under the hypothesis of tangential geostrophy. Then the associated geostrophic pressure, whose order of magnitude is about 1000 Pa, is computed. The surface topography induced by this pressure field is computed using Love numbers, and is a few millimetres. The mass redistribution gravitational potential induced by these deformations and, in particular, the zonal components of the related surface gravitational potential perturbation (J2, J3 and J4 coefficients), are calculated. Overall perturbations for the J2 coefficient of about 10–10, for J3 of about 10–11 and for J4 are found of about 0.3×10–11. Finally, these theoretical results are compared with recent observations of the decadal variation of J2 from satellite laser ranging. Results concerning J2 can be described as follows: first, they are one order of magnitude too small to explain the observed decadal variation of J2 and, second, they show a significant linear trend over the last 40 years, whose rate of decrease amounts to 7% of the observed value. 相似文献
967.
968.
利用面向对象的分类方法从IKONOS全色影像中提取河流和道路 总被引:24,自引:0,他引:24
传统的基于像素的统计特征的分类方法在处理高分辨率影像的分类问题上遇到了很大的困难。本研究利用面向对象的影像分析方法对IKONOS全色影像进行了河流与道路的分类,包括利用影像对象的光谱特征的初次分类和利用子目标对象的线特征的二次分类两个过程;其中初次分类由于仅依据光谱信息,不能很好地将河流或道路与其他光谱特征相似的地物区分开,而通过引入子目标的形状特征进行二次分类,就可以准确地将河流与道路提取出来。试验结果表明,面向对象的分类方法能够满足高分辨率或纹理影像的分类需要,具有很大的应用潜力。 相似文献
969.
介绍了高桥墩的垂直度观测方法和精度分析,推导出一系列实用公式,观测方法简单,结果精确可靠。利用这种方法能快速有效地判断出桥墩的倾斜量,及时采取相应调整措施,以保证桥墩的垂直性。 相似文献
970.
利用压缩感知方法解决SAR三维层析成像中的频谱估计问题,弥补了传统谱估计方法的一些缺陷,准确重建了来自不同散射目标的回波信号。实验结果表明,该方法不仅能够有效地区分影像中同一像元中的多个散射体,而且可以较为准确地获取目标散射体相对强度分布及高程信息,为目标的分类和识别提供更多依据,显现出对数据量要求较少及抗噪声性能强等优势。 相似文献