高分辨率立体测绘卫星技术研究

本文针对高精度立体测绘卫星设计和实现中的关键技术难点,在充分分析国内外测绘卫星的发展历程和技术特点的基础上,结合测绘卫星的设计关键——高图像定位精度技术实现,对高分辨率立体测绘卫星的设计约束条件、测绘体制选取、卫星载荷和平台关键产品的设计重点难点等进行了分析研究。分析指出了三线阵测绘体制、两线阵测绘体制和单线阵测绘体制的技术特点、实现约束和在测绘卫星不同发展阶段的工程实现优势;明确了基于目前工程技术水平,两线阵测绘体制在大范围、高分辨率、高精度测绘卫星中应用的特有优势。提出了测绘卫星高定位精度关键技术的设计要素和解决途径。结合国内首颗亚米级高精度立体测绘卫星——高分七号（GF-7）卫星的设计状态,说明卫星在保证测绘任务要求方面所提出的多项技术创新,并给出卫星用户对卫星在国土测绘及其他扩展应用中的测试结果。在轨数据表明,依照本论文提出的高分辨率立体测绘卫星系统设计方法,高分七号卫星在轨性能全面满足且部分优于设计指标,达到了世界的领先水平。论文的研究成果为后续更大比例尺的立体测绘卫星设计提供了有力参考。     

2010年玉树7．1级地震前后气温变化分析

利用距平方法分析了2010年青海玉树7．1级地震前后玉树及周边台的气温变化,结果表明,在玉树地震前,从2001年到2010年,气温存在一个长达10年的趋势上升变化,总升温幅度约1．7℃,地震后气温很快下降恢复到趋势上升前的水平。比较玉树气温与周边气温的变化过程,在玉树地震前后,玉树气温变化与周边气温变化存在明显的差异,初步分析认为玉树气温的异常变化与玉树地震孕育和发生存在一定的联系。     

Ordovician backarc‐basin metadolerite and metabasalt of the South Kitakami Terrane,Northeast Japan

Basement rocks that occur along the northern margin of the South Kitakami Terrane in Japan consist of Ordovician ultramafic rocks (Hayachine ultramafic complex), gneissose amphibolite (Kuromoriyama amphibolite), and mafic rocks (Kagura igneous rocks, KIR). The KIR are composed of metagabbro, metadolerite, metabasalt, and minor felsic–intermediate dikes. Although the KIR contain green hornblende due to metamorphism of greenschist to epidote–amphibolite facies, they rarely retain primary brown hornblende. Approximately 30% of the metabasalt shows porphyritic textures, with phenocrysts of saussuritized plagioclase and/or altered mafic minerals. The geochemistry of the common metadolerite and metabasalt of the KIR shows a tholeiite trend, a low TiO₂ content, and high Th/Nb and Ti/V ratios. The KIR are therefore indicative of a supra‐subduction zone tectonic setting, which implies a backarc origin (as also indicated by discrimination diagrams). Trace element patterns of the KIR resemble those of the backarc‐basin basalt of the Japan and Yamato basins in the Japan Sea. We propose that the KIR formed during backarc spreading from the Ordovician to Early Silurian. This view is supported by the geochemical data, the tectonic setting of the Hayachine ultramafic rocks, and the provenance of clastics within Silurian sedimentary rocks.     

Zircon U–Pb ages of plutonic rocks in the southern Abukuma Mountains: Implications for Cretaceous geotectonic evolution of the Abukuma Belt

Plutonic rocks in the southern Abukuma Mountains include gabbro and diorite, fine‐grained diorite, hornblende–biotite granodiorite (Ishikawa, Samegawa, main part of Miyamoto and Tabito, Kamikimita and Irishiken Plutons), biotite granodiorite (the main part of Hanawa Pluton and the Torisone Pluton), medium‐ to coarse‐grained biotite granodiorite and leucogranite, based on the lithologies and geological relations. Zircon U–Pb ages of gabbroic rocks are 112.4 ±1.0 Ma (hornblende gabbro, Miyamoto Pluton), 109.0 ±1.1 Ma (hornblende gabbro, the Hanawa Pluton), 102.7 ±0.8 Ma (gabbronorite, Tabito Pluton) and 101.0 ±0.6 Ma (fine‐grained diorite). As for the hornblende–biotite granodiorite, zircon U–Pb ages are 104.2 ±0.7 Ma (Ishikawa Pluton), 112.6 ±1.0 Ma (Tabito Pluton), 105.2 ±0.8 Ma (Kamikimita Pluton) and 105.3±0.8 Ma (Irishiken Pluton). Also for the medium‐ to fine‐grained biotite granodiorite, zircon U–Pb ages are 106.5±0.9 Ma (Miyamoto Pluton), 105.1 ±1.0 Ma (Hanawa Pluton) and the medium‐ to coarse‐grained biotite granodiorite has zircon U–Pb age of 104.5 ±0.8 Ma. In the case of the leucogranite, U–Pb age of zircon is 100.6 ±0.9 Ma. These data indicate that the intrusion ages of gabbroic rocks and surrounding granitic rocks ranges from 113 to 101 Ma. Furthermore, K–Ar ages of biotite and or hornblende in the same rock samples were dated. Accordingly, it is clear that these rocks cooled down rapidly to 300 °C (Ar blocking temperature of biotite for K–Ar system) after their intrusion. These chronological data suggest that the Abukuma plutonic rocks in the southern Abukuma Mountains region uplifted rapidly around 107 to 100 Ma after their intrusion.     

SHRIMP U–Pb zircon dating of the Kinshozan Quartz Diorite from the Kanto Mountains,Japan: Implications for late Paleozoic granitic activity in Japanese Islands

The new result of SHRIMP U–Pb zircon dating of the Kinshozan Quartz Diorite from the Kanto Mountains, Japan, provides 281.5 ± 1.8 Ma. The age is 30 m.y. older than the available age of the Kinshozan Quartz Diorite obtained by hornblende K–Ar method. The new U–Pb zircon age represents the time of crystallization of the Kinshozan Quartz Diorite. The hornblende K–Ar age indicates the time that the Kinshozan Quartz Diorite cooled down to 500 °C which is the closure temperature of the systematics. Permian granites are found in small exposures in Japan, and frequently referred to as 250 Ma granites. The Kinshozan Quartz Diorite is considered as a type of the 250 Ma granites, and the age was influential in establishing a model of Paleozoic tectonic evolution for the Japanese Islands. The new age of the Kinshozan Quartz Diorite provides the opportunity to re‐examine the model. The Kinshozan Quartz Diorite and other Permian granites in the south of the Median Tectonic Line of Japan were constituents of the Paleo‐Ryoke Belt. The geochemical characteristics of the granitic rocks in the Paleo‐Ryoke Belt indicated that the granitic rocks were formed in a primitive island arc environment, and the new trace element data also support this interpretation. Examination of the available data and results of the present study suggests the late Paleozoic granitic activity in Japan as follows. At about 310–290 Ma, arc magmatism generated adakitic granites and other granites in the South Kitakami Belt. Quartz diorite and tonalites of primitive characteristic, such as the Kinshozan Quartz Diorite and granites in the Maizuru Belt appear to have been formed at the immature island arc, and accreted to the Japanese Islands at the end of Paleozoic or early Mesozoic era. During 260–240 Ma, granitic activity took place in the Hida and Maizuru Belts as a part of the Asian continent.     

Tsunami deposit associated with the 2011 Tohoku‐oki tsunami in the Hasunuma site of the Kujukuri coastal plain,Japan

We describe the detailed sedimentary characteristics of a tsunami deposit associated with the 2011 Tohoku‐oki tsunami in Hasunuma, a site on the Kujukuri coastal plain, Japan. The thick tsunami deposit was limited to within 350 m from the coastline whereas the inundation area extended about 1 km from the coastline. The tsunami deposit was sampled by excavation at 29 locations along three transects and studied using peels, soft‐X imaging and grain‐size analysis. The deposit covers the pre‐existing soil and reached a maximum measured thickness of 35 cm. It consists mainly of well‐sorted medium to fine sand. On the basis of sedimentary structures and changes in grain size, we divided the tsunami deposit into several sedimentary units, which may correspond to multiple inundation flows. The numbers of units and their sedimentary features vary among the three transects, despite the similar topography. This variation implies a considerable influence of local effects such as elevation, vegetation, microtopography, and distance from footpaths, on the tsunami‐related sedimentation.     

基于Landsat-7ETM+SLC-OFF影像的山地冰川流速提取与评估——以Karakoram锡亚琴冰川为例

Landsat-7机载扫描行校正器（Scan Line Corrector,SLC）失效后的ETM+影像（SLC-OFF影像）约有22%的数据缺失,严重限制了该影像在冰川研究中的应用,特别对长期缺乏高质量遥感影像的高亚洲地区冰川运动连续监测产生较大影响。以Karakoram 中部最大的锡亚琴冰川为例,初步评估了Landsat-7 ETM+SLC-OFF影像在山地冰川表面流速提取方面的适用性和可行性。选取2009年和2010年两景SLC-OFF影像,运用局部直方图匹配法（Local Linear Histogram Match,LLHM）和加权线性回归法（Weighted Liner Regression,WLR）修复缺失数据条带,并利用亚像元互相关方法对修复后两景影像进行冰川表面流速估算。结果表明,LLHM和WLR两种方法均能有效修复冰川区Landsat-7 SLC-OFF影像,其冰流估算结果与同期Landsat-5TM 影像的冰流结果较为一致,三者冰流速估算精度分别为±5.9m ·a^-1、±6.3m ·a^-1和±4.0m ·a^-1,验证了Landsat-7 SLC-OFF 影像在山地冰川流速监测中的应用潜力。     

自由落体式绝对重力仪测量数据处理方法研究

通过处理FG5和A10型绝对重力仪实测数据,探索g7软件的内部算法。若采用软件手册提供的观测方程和算法,A10测量数据的解算结果与软件处理结果的差值在3 μGal以内,而FG5相差较大。在对观测方程和时间观测量进行改正以后,得到的FG5测量数据解算结果与g7软件处理结果的差值在－0.1~0.1 μGal之间。由此认为,改正后的模型和算法与g7软件所采用的解算模型和算法基本一致。     

Are Seyfert 2 Galaxies without Polarized Broad Emission Lines More Obscured？

New XMM-Newton data of seven Seyfert 2 galaxies with optical spectropolarimet- ric observations are presented. An analysis of the 0.5 - 10 keV spectra shows that four Seyfert 2 galaxies with polarized broad lines (PBLs) are absorbed by NH < 1024 cm-2, while two of three Seyfert 2 galaxies without PBLs show evidence of Compton-thick obscuration, support- ing the conclusion that Seyfert 2 galaxies without PBLs are more obscured than those with PBLs. Adding the measured obscuration indicators (NH, T ratio, and Fe Kα line EW) of six luminous AGNs to our previous sample improves the significance level of the difference in absorption from 92.3% to 96.3% for NH, 99.1% to 99.4% for T ratio, and 95.3% to 97.4% for Fe Kα line EW. The present results support and enhance the suggestions that the absence of PBLs in Seyfert 2 galaxies can be explained by larger viewing angles of the line of sight to the putative dusty torus, which leads to the obscuration of the broad-line scattering screen, as expected in the unification model.     

Morphologic and sedimentologic patterns of active aeolian dune‐fields on the east coast of Maranhão,northeast Brazil

The eastern portion of the Maranhão coast is characterized by large active dune‐fields located in a tropical setting. This article combines the analysis of dune‐field morphologic patterns with the classical analysis of grain size and heavy minerals to study the sedimentary dynamics of the active aeolian system in this region. Based on the heavy mineral analysis, the main sedimentary suppliers feeding the system are the westward alongshore drift bringing sand from the coast east of the Parnaíba River mouth and the river itself. The absence of well‐defined variation patterns of the two morphometric parameters studied, dune spacing and crest length, reflects complex sedimentary dynamics and transport pathways, inside the aeolian system, despite the unidirectional wind. During the wet season, the interdune plains are flooded and the system is intensely reworked by intermittent drainages. During the dry season, the deposits formed by the drainages and interdune lakes become temporary internal sedimentary sources for the system. Due to this combined aeolian‐fluvial transport, the sediment source area has a planar geometry, with contributions from the beach and interdune plains, and not linear as expected in a typical case of source only in the beach. The areal limits of the dune‐fields is the main boundary condition controlling the dune‐field patterns, as dune spacing and crest length, by changing the sedimentary inflow–outflow balance and interactions between migration dunes. Copyright © 2015 John Wiley & Sons, Ltd.