地球物理抗差估计和广义逆方法   总被引：15，自引：3，他引：12       下载免费PDF全文

李平  许厚泽 《地球物理学报》2000,43(2):233-240

为进行观测数据误差较大的地球物理资料的反演,引人抗差估计,称作地球物理抗差估计;为使病态方程组的反演解更可靠,又结合广义逆方法进行了算法改进．首先介绍抗差最小二乘（ＲＬＳ）的基本原理,然后推寻出适于广义逆反演方法的改进算式,最后举例加以讨论．分析表明,抗差估计可以有效地抑制地球物理观测异常的影响,得出正常模式下的较好估计值;而用改进后的算式和广义逆反演可以使反演解更加改善,不仅如此,改进后的方法还能直接给出解估计的可靠性评价．  相似文献   

Real-time prediction of the peak suspended sediment concentration and sediment yield of the Lao-Nung River during storms     

Pi-Chih HSU  Ching-Nuo CHEN  Chang-Tai TASI 《国际泥沙研究》2011,26(2):163-180

Based on rainfall erosion of soil and suspended sediment transport in storm events, a method is proposed to predict peak suspended sediment concentration and suspended sediment yield in watersheds based on rainfall characteristics prior to peak rainfall intensity. The rainfall characteristics factors that dominate peak suspended sediment concentration C_p are rainfall erosion factor R_ef, first peak rainfall intensity of area-average rainfall i_p1 and antecedent precipitation index I_ap; the rainfall characteristics factors that dominate suspended sediment yield Y_ss in storm events are total rainfall P, suspended sediment yield factor R_sf and antecedent precipitation index I_ap. This research focuses on watersheds in Liau-Kwei observation station along Lao-Nung River in southern Taiwan as the research object, and adopts the PSED-model to simulate the discharge hydrograph, suspended sediment concentration hydrograph and suspended sediment yield in 11 storm events for analysis. The analytical results show that there is a good correlation between the above-mentioned rainfall characteristics factors and C_p as well as Y_ss, thus enabling C_p and Y_ss to be predicted by using Expressions (13) and (14). These two expressions are utilized to predict C_p and Y_ss of Typhoon Morakot in 2009, and the results are compared with those from simulation by using the PSED-model. The result of comparison shows there is a good capability in predicting. For the watersheds where it is necessary to predict C_p and Y_ss of a storm event for the benefit of effective operation of water resource facilities, the aforesaid rainfall characteristics factors can be utilized to establish applicable models for prediction.  相似文献   

地球各圈层相互作用的大地测量研究和检测   总被引：3，自引：0，他引：3  

许厚泽 《大地测量与地球动力学》2002,22(4):1-5

大地测量资料，包括在球表面运动，地球引力场及地球整体自转运动的观测资料，是研究地球各圈层相互作用的重要地表约束，探讨了大地测量用于这一研究领域中的几个重要科学前沿问题。  相似文献   

恒星尘埃的实验室研究--实验天体物理学   总被引：1，自引：0，他引：1  

徐伟彪 《天文学报》2006,47(1):1-8

原始球粒陨石含有来自恒星的微小固体颗粒(微米级),这些尘埃的同位素组成与太阳系物质截然不同,它们是目前唯一能直接获得的恒星固体样品．已发现的恒星尘埃有金刚石、石墨、碳化硅、刚玉、尖晶石、氮化物、和硅酸盐等,它们的母体恒星包括红巨星,AGB恒星、新星和超新星．对恒星尘埃的研究,使得更深入地了解星系的化学演化历史、恒星内部的核反应和湍流机制、恒星大气中尘埃的形成、星际介质物理现象等．恒星尘埃把天体物理领域延伸到了微观世界,它有机地结合了地球化学实验技术和天体物理理论,开辟了一门崭新的天文学分支实验天体物理学．  相似文献   

Petrogenesis of Grove Mountains 020090: An enriched “lherzolitic” shergottite     

Yun JIANG  Weibiao HSU 《Meteoritics & planetary science》2012,47(9):1419-1435

Grove Mountains (GRV) 020090 is a “lherzolitic” shergottite found in the Grove Mountains, Antarctica. It exhibits two distinct textures: poikilitic and nonpoikilitic. In poikilitic areas, large pyroxene oikocrysts enclose subhedral olivine and chromite chadacrysts. Pyroxene oikocrysts are zoned from pigeonite cores to augite rims. In nonpoikilitic areas, olivine, pyroxene, and interstitial maskelynite occur as major phases, and minor phases include chromite and merrillite. Compared with typical “lherzolitic” shergottites, GRV 020090 contains a distinctly higher abundance of maskelynite (19 vol%). Olivine and pyroxene are more ferroan (Fa_28–40, En_57–72Fs_24–31Wo_4–14 and En_46–53Fs_17–21Wo_26–35), and maskelynite is more alkali‐rich (Ab_43–65Or_2–7). The major phases, whole‐rock (estimated) and fusion crust of GRV 020090, are relatively enriched in light rare earth elements (LREE), similar to those of the geochemically enriched basaltic shergottites, but distinct from those of LREE‐depleted “lherzolitic” shergottites. Combined with a high oxygen fugacity of log fO₂ = QFM ? 1.41 ± 0.04 (relative to the quartz‐fayalite‐magnetite buffer), it is clear that GRV 020090 sampled from an oxidized and enriched mantle reservoir similar to those of other enriched shergottites. The calculated REE abundances and patterns of the melts in equilibrium with the cores of major phases are parallel to but higher than that of the whole rock, suggesting that GRV 020090 originated from a single parent magma and experienced progressive fractional crystallization in a closed system. The crystallization age recorded by baddeleyite is 192 ± 10 (2σ) Ma, consistent with the young internal isochron ages of enriched shergottites. Baddeleyite dating results further demonstrated that the young ages, rather than ancient ages (>4 Ga), appear to represent the crystallization of Martian surface lava flow. GRV 020090 shares many similarities with Roberts Massif (RBT) 04261/2, the first enriched “lherzolitic” shergottite. Detailed comparisons suggest that these two rocks are petrologically and geochemically closely related, and probably launch paired.  相似文献   

Stress changes on major faults caused by 2013 Lushan earthquake and its relationship with 2008 Wenchuan earthquake   总被引：17，自引：0，他引：17  

SHAN Bin  XIONG Xiong  ZHENG Yong  JIN BiKai  LIU ChengLi  XIE ZhuJun  HSU HouTze 《中国科学:地球科学(英文版)》2013,(7):1169-1176

On April 20, 2013, an Ms7.0 earthquake occurred in Ya’an-Lushan region, Sichuan Province, China, killing and injuring morethan one thousand people. Therefore, it is critical to outline the areas with potential aftershocks before reconstruction andre-settlement as to avoid future disasters. Based on the elastic dislocation theory and multi-layered lithospheric model, we calculate the co-and post-seismic stress changes caused by the Wenchuan and Lushan earthquakes to discuss the relationshipbetween Mw7.9 Wenchuan earthquake and Ms7.0 Lushan earthquake, the influences on the distribution of aftershock caused bythe Lushan earthquake, and the stress changes on major faults in this region. It is shown that the Coulomb failure stress increment on the hypocenter of Lushan earthquake caused by the Wenchuan earthquake is about 0.0037-0.0113 MPa. And the possible maximum value (0.0113 MPa) is larger than the threshold of stress triggering. Therefore, the occurrence of Lushanearthquake is probably effectively promoted by the Wenchuan earthquake. The aftershock distribution is well explained by theco-seismic stress changes of Lushan earthquake. By the two ends of the rupture of Lushan earthquake with increased Coulombfailure stress, a lack of aftershock recordings indicates the high seismic hazard. The stress accumulation and correspondingseismic hazard on the Kangding-Dafu segment of the Xinshuihe fault, the Beichuan-Yingxiu fault, the Pengxian-Guanxianfault, and the Ya’an fault are further increased by the Lushan earthquake and post-seismic process of Wenchuan earthquake.  相似文献   

Spectral analysis for recovering the Earth's gravity potential by satellite gravity gradients          下载免费PDF全文

CAI Lin  ZHOU Ze-Bing  ZHU Zhu  GAO Fang  HSU Houtse 《地球物理学报》2012,55(5)

根据仪器功率谱密度和重力位系数阶方差的定义,本文建立了卫星重力梯度测量噪声功率谱密度与重力场模型的误差阶方差的直接对应关系,并基于此讨论了重力梯度测量精度、卫星轨道高度以及运行时间对地球重力场恢复精度的影响.相比于传统的基于最小二乘法评估卫星载荷噪声对地球重力场恢复精度的影响而言,本文提出的方法简单、直接,有助于快速设计和确定卫星重力测量计划的有关参数.  相似文献   

华北克拉通岩石圈三维密度结构   总被引：6，自引：4，他引：2       下载免费PDF全文

王新胜  方剑  许厚泽  郑伟 《地球物理学报》2012,55(4):1154-1160

显生宙以来华北克拉通岩石圈遭到破坏,这一现象的科学问题已受到世界地学家广泛关注.本文首先将地震层析成像反演得到的P波速度扰动转化为密度扰动,以此作为初始密度模型,然后利用布格重力异常反演得到了华北克拉通岩石圈高分辨三维密度结构.为了避开大型稀疏矩阵求逆计算,提高计算效率,我们将代数重构技术用于密度反演解算.反演结果表明:华北克拉通岩石圈密度在横向和纵向上均存在明显的不均匀性,密度分布形态与地表构造格局有很好的相关性;研究区地壳整体表现为低密度异常,地壳以下岩石圈部分则以高密度异常为主;鄂尔多斯块体地壳范围内以低密度异常为主,80~120 km深度上为呈南北两端集中分布的高密度异常,并分别与秦岭造山带和阴山造山带的高密度异常分布相连,这暗示了鄂尔多斯块体可能受到了来自其南北两端造山带深部动力学过程的影响;80~120 km深度上,华北克拉通东部地区呈现出显著的南北向非均匀的高密度异常,这表明遭到破坏后该地区上地幔物质分布具有强烈的南北向非均匀性.  相似文献   

Petrography,mineralogy, and geochemistry of lunar meteorite Sayh al Uhaymir 300     

Weibiao HSU  Aicheng ZHANG  Rainer BARTOSCHEWITZ  Yunbin GUAN  Takayuki USHIKUBO  Urs KRÄHENBÜHL  Rainer NIEDERGESAESS  Rudolf PEPELNIK  Ulrich REUS  Thomas KURTZ  Paul KURTZ 《Meteoritics & planetary science》2008,43(8):1363-1381

Abstract— We report here the petrography, mineralogy, and geochemistry of lunar meteorite Sayh al Uhaymir 300 (SaU 300). SaU 300 is dominated by a fine‐grained crystalline matrix surrounding mineral fragments (plagioclase, pyroxene, olivine, and ilmenite) and lithic clasts (mainly feldspathic to noritic). Mare basalt and KREEPy rocks are absent. Glass melt veins and impact melts are present, indicating that the rock has been subjected to a second impact event. FeNi metal and troilite grains were observed in the matrix. Major element concentrations of SaU 300 (Al₂O₃ 21.6 wt% and FeO 8.16 wt%) are very similar to those of two basalt‐bearing feldspathic regolith breccias: Calcalong Creek and Yamato (Y‐) 983885. However, the rare earth element (REE) abundances and pattern of SaU 300 resemble the patterns of feldspathic highlands meteorites (e.g., Queen Alexandra Range (QUE) 93069 and Dar al Gani (DaG) 400), and the average lunar highlands crust. It has a relatively LREE‐enriched (7 to 10 x CI) pattern with a positive Eu anomaly (?11 x CI). Values of Fe/Mn ratios of olivine, pyroxene, and the bulk sample are essentially consistent with a lunar origin. SaU 300 also contains high siderophile abundances with a chondritic Ni/Ir ratio. SaU 300 has experienced moderate terrestrial weathering as its bulk Sr concentration is elevated compared to other lunar meteorites and Apollo and Luna samples. Mineral chemistry and trace element abundances of SaU 300 fall within the ranges of lunar feldspathic meteorites and FAN rocks. SaU 300 is a feldspathic impact‐melt breccia predominantly composed of feldspathic highlands rocks with a small amount of mafic component. With a bulk Mg# of 0.67, it is the most mafic of the feldspathic meteorites and represents a lunar surface composition distinct from any other known lunar meteorites. On the basis of its low Th concentration (0.46 ppm) and its lack of KREEPy and mare basaltic components, the source region of SaU 300 could have been within a highland terrain, a great distance from the Imbrium impact basin, probably on the far side of the Moon.  相似文献   

基于GRACE Follow-On卫星重力梯度法精确反演地球重力场   总被引：2，自引：1，他引：1       下载免费PDF全文

郑伟  许厚泽  钟敏  员美娟 《地球物理学报》2014,57(5):1415-1423

由于GRACE Follow-On双星系统等效于基线长为星间距离的一维水平重力梯度仪,因此本文基于GRACE Follow-On卫星重力梯度法开展了精确和快速反演下一代地球重力场的可行性论证研究. 研究结果表明：第一,基于GRACE Follow-On卫星重力梯度法（GFO-SGGM）,利用卫星轨道参数（轨道高度250 km、星间距离50 km、轨道倾角89°、轨道离心率0.001）、关键载荷测量精度（星间距离10^-6 m、星间速度10^-7 m·s^-1、星间加速度10^-10 m·s^-2、轨道位置10^-3 m、轨道速度10^-6 m·s^-1、非保守力10^-11 m·s^-2）、观测时间30天和采样间隔10 s反演了120阶地球重力场,在120阶处累计大地水准面精度为9.331×10^-4 m. 第二,在120阶内,利用将来GRACE Follow-On双星反演地球重力场精度较现有GRACE双星平均提高61倍,因此GRACE Follow-On卫星重力梯度法是进一步提高地球重力场反演精度的优选方法. 第三,下一代GRACE Follow-On计划较当前GRACE计划的优点如下：轨道高度更低（200~300 km）、载荷精度更高（10^-7 ~10^-9 m·s^-1）和星间距离更短（50~100 km）.  相似文献