合成孔径雷达干涉测量(InSAR)在地面形变监测中的应用   总被引：13，自引：0，他引：13  

张拴宏  纪占胜 《中国地质灾害与防治学报》2004,15(1):112-117,128

运用合成孔径雷达干涉及其差分技术(InSAR及D-InSAR)进行地面微位移监测，是近年来发展起来并得到日益重视的新方法。对不同地区地面形变的最新研究结果表明，合成孔径雷达干涉及其差分技术在地震形变、冰川运移、活动构造、地面沉降及滑坡等研究与监测中有广阔的应用前景，具有不可替代的优势。 与其它方法(如GPS监测等)相比，用InSAR及D-InSAR进行地面形变监测的主要优点在于：(1)覆盖范围大，方便迅速：(2)成本低，不需要建立监测网；(3)空间分辨率高，可以获得某一地区连续的地表形变信息；(4)可以监测或识别出潜在或未知的地面形变信息：(5)全天候，不受云层及昼夜影响。但是由于系统本身因素以及地面植被、湿度及大气条件变化的影响，精度及适用性受到一定的限制，需要在实践中不断加以完善和提高，并与地质研究及其它方法相结合。 为了弥补传统InSAR及D-InSAR方法在地面形变监测方面的不足，提高其精度，近期引入了一种称为永久散射点(PS)的方法。此方法通过选取一定时期内表现出稳定干涉行为的孤立点，克服了许多妨碍传统雷达干涉技术的分辨率、空间及时间上基线限制等问题，使InSAR在城市及岩石出露较好地区地面形变监测精度大大提高，在一定的条件下精度可达到mm级。  相似文献   

Current German geography in a globalizing world of science A documentation and personal interpretation     

Eckart Ehlers 《GeoJournal》1998,45(1-2):57-67

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Stellar evolution models for Z = 0.0001 to 0.03     

Onno R. Pols  Klaus-Peter Schro¨der  Jarrod R. Hurley  Christopher A. Tout  & Peter P. Eggleton 《Monthly notices of the Royal Astronomical Society》1998,298(2):525-536

We have calculated a grid of empirically well tested evolutionary tracks with masses M between 0.5 and 50 M⊙, spaced by approximately 0.1 in log M , and with metallicities Z  = 0.0001, 0.0003, 0.001, 0.004, 0.01, 0.02 and 0.03. We use a robust and fast evolution code with a self-adaptive non-Lagrangian mesh, which employs the mixing-length theory but treats convective mixing as a diffusion process, solving simultaneously for the structure and the chemical composition. The hydrogen and helium abundances are chosen as functions of the metallicity: X  = 0.76 − 3.0 Z Y  = 0.24 + 2.0 Z .   Two sets of models were computed, one without and one with a certain amount of enhanced mixing or 'overshooting'. This amount has been empirically chosen by means of various sensitive tests for overshooting: (1) the luminosity of core helium burning (blue loop) giants of well-known mass, (2) the width of the main sequence as defined by double-lined eclipsing binaries with well-measured masses and radii, and (3) the shape and implied stellar distribution of isochrones of various open clusters. The first two tests have been the subject of previous papers, the third test is discussed in this paper. On the basis of these tests, we recommend the use of the overshooting models for masses above about 1.5M ⊙.   We describe here the characteristics of the models, the procedure for constructing isochrones for arbitrary age and metallicity from the models, and the performance of these isochrones for several intermediate-age and old open clusters. All original models are available in electronic form and we describe the means by which they may be obtained.  相似文献   

Methanol masers and their environment at high resolution     

C. J. Phillips  R. P. Norris  S. P. Ellingsen  & P. M. McCulloch 《Monthly notices of the Royal Astronomical Society》1998,300(4):1131-1157

We have used the Australia Telescope Compact Array (ATCA) to make high-resolution images of the 6.7-GHz 5₁ → 6₀A⁺ maser transition of methanol towards 33 sources in the Galactic plane. Including the results from 12 methanol sources in the literature, we find that 17 out of 45 sources have curved or linear morphology. Most of the 17 have a velocity gradient along the line, which is consistent with masers lying in an edge-on circumstellar disc surrounding a massive star. We also made simultaneous continuum observations of the sources at 8.6 GHz, in order to image any associated H  ii region. 25 of the sources are associated with an ultracompact H  ii region, with a detection limit of ∼0.5 mJy beam⁻¹. We argue that the methanol sources without an associated H  ii region represent less massive embedded stars, not an earlier stage in the lifetime of the star, as previously suggested.  相似文献   

Morphology of star formation regions in irregular galaxies     

Noah Brosch  Ana Heller  & Elchanan Almoznino 《Monthly notices of the Royal Astronomical Society》1998,300(4):1091-1097

The location of H  II regions, which indicates the locus of present star formation in galaxies, is analysed for a large collection of 110 irregular galaxies (Irr) imaged in Hα and nearby continuum. The analysis is primarily by visual inspection, although a two-dimensional quantitative measure is also employed. The two different analyses yield essentially identical results. H  II regions appear preferentially at the edges of the light distribution, predominantly on one side of the galaxy, contrary to what is expected from stochastic self-propagating star formation scenarios. This peculiar distribution of star-forming regions cannot be explained by a scenario of star formation triggered by an interaction with extragalactic gas, or by a strong one-armed spiral pattern.  相似文献   

The record of paleoclimatic change from stalagmites and the determination of termination II in the south of Guizhou Province,China     

Zhang?MeiliangEmail author  Yuan?Daoxian  Lin?Yushi  Cheng?Hai  Qin?Jiaming  Zhang?Huiling 《中国科学D辑(英文版)》2004,47(1):1-12

A high-resolution climate record from 163.00 kaBP to 113.80 kaBP has been obtained through TIMS-U series dating and carbon and oxygen isotope analysis of the three large stalagmites from two caves in the south of Guizhou Province, China. The record of the oxygen isotopes from the stalagmites reveals that the undulation characteristics between the cooling event of the glacial period and the warming event of the interglacial period in the research area can compare well to those of ice cores, lake sediments, loess and deep sea sediments on the scale of ten-thousand years or millennium time scale. The climate undulation provided by the record of the stalagmites has a coherence with the global changes and a tele-connection to the paleoclimate changes in the north polar region. Our results suggest that the direct dynamics of paleo-monsoon circulation changes reflected in the record of the stalagmites might be caused by changes of the global ice volume, and in turn related to various factors, including the solar radiation strength at the mid-latitudes in the Northern Hemisphere, the southern extension of the ice-rafted event in the North Atlantic, and changes of the equatorial Pacific sea surface temperature at the low-latitudes. Using °¹⁸O values, we have calculated the temperatures and the results show that the temperature difference between the penultimate glacial period (with an average temperature of 8.1°C, and a minimum temperature range from 0.65°C to-1.43°C at stage 6) and the last interglacial period (with an average temperature of 18.24°C at sub-stage 5e) was about 10°C. This temperature difference from the record of the stalagmites corresponds in general to the record temperature variation (about 10°C) of measured ice cores. The climate records from the three stalagmites in the two caves have shown that the circulation strength of the Asian summer monsoon and the winter monsoon in the penultimate glacial period and the last inter-glacial period had a clear change. With the TIMS-U series method, termination II of the penultimate glacial period has been precisely dated at an age of (129.28± 1.10) kaBP for the three stalagmites in the south of Guizhou Province, China. This borderline age represents the beginning of the last interglacial period or the boundary between the Middle Pleistocene and the Late Pleistocene, and corresponds to the beginning age of the last interglacial period shown by the ice cores and in the SPECMAP curve of the marine oxygen isotopes. The chronology determination of termination II is not only of stratigraphic and chronological significance, but also lays an important foundation for discussing the short time scales of climate oscillation and rapidly changing events of paleoclimate in the circulation region of the East Asian monsoon.  相似文献   

基于出版的地图符号库系统的建立   总被引：2，自引：1，他引：2  

车森  刘真 《测绘学院学报》2003,20(3):216-219

提出并解决了基于出版的地图符号库需要解决的关键技术：符号制作软件的设计、符号与属性库的连接、RGB色彩到CMYK色彩的转换、基于出版的地图符号分层、PS文件的生成；在此基础上论述了全数字出版系统中建立地图符号库系统的方法。  相似文献   

PS剂驱油提高采收率室内评价研究     

谢俊  张曙光  梁会珍 《矿物岩石》2002,22(4):87-89

表面活性剂驱油是化学驱的方法之一，即在常规注水条件下，通过在注入水中加入添加剂来降低油水界面张力，改变岩石颗粒表面的润湿性，使油膜从岩石面上冲洗下来，并在驱替压差的作用下流入生产井，从而达到增产的目的。PS表面活性剂具有这种作用，能够提高原油的采收率。  相似文献   

太平洋岛国对澳大利亚地缘战略影响的历史考察   总被引：1，自引：1，他引：0  

姜芸 《世界地理研究》2019,28(2):141-148

历史上太平洋岛国对澳大利亚地缘战略的影响以第二次世界大战为分水岭,主要分为三个阶段：二战前是地缘战略缺失阶段,当时澳大利亚无视周边地缘环境,将国家安全系于遥远英帝国的庇护,忽视近邻岛屿的防御屏障作用,导致国家遭受战火;二战时期是地缘战略构建阶段,随着澳美战时同盟成立,太平洋上的海空航线成为澳大利亚的“生命线”,澳大利亚的独立防务意识也不断加强,意图凭借《澳新协定》将太平洋岛国纳入势力范围;二战后是地缘战略丰富阶段,在太平洋岛国发展问题日益突出和岛屿地区安全态势日趋复杂的背景下,澳大利亚实施援助战略以促进地区的繁荣与稳定。未来,澳大利亚将继续保持该地区最大援助国的地位。  相似文献   

一种改进的InSAR城市地面沉降监测精度评价方法     

杨帆  王道顺  张磊  张子文 《测绘通报》2019,(2):54-57,85

针对InSAR沉降监测精度评定方法的单一性,综合考虑建筑物自身沉降和时空基准难以统一的问题,构建了改进的反距离权重插值模型。以宁波东部新城某沉降区域的PS-InSAR监测结果为试验数据,在统一时空基准的前提下,利用改进IDW插值模型对监测结果进行精度评定,并以交叉验证的方式验证了该插值方法的准确性。试验证明：通过对比两个实测水准点,使用改进的IDW插值获取的InSAR监测结果误差为0.3和0.8,相比于普通IDW和Kriging方法提高了大约1.1 mm。  相似文献