A case study of using external DEM in InSAR DEM generation

Synthetic aperture radar interferometry (InSAR) has been used as an innovative technique for digital elevation model (DEM) and topographic map generation. In this paper, external DEMs are used for InSAR DEM generation to reduce the errors in data processing. The DEMs generated from repeat-pass InSAR are compared. For steep slopes and severe changes in topography, phase unwrapping quality can be improved by subtracting the phase calculated from an external DEM. It is affirmative that the absolute height accuracy of the InSAR DEM is improved by using external DEM. The data processing was undertaken without the use of ground control points and other manual operation.     

地质图空间数据库建设质量控制方法研究

针对地质数据库建设的质量控制问题,本文依托1：50 000区域地质图空间数据库建设成果数据质量控制,通过对区域地质图空间数据库建设过程中可能产生的质量问题进行总结和分析,系统阐述了空间数据库成果数据质量控制的基本理论与方法技术。实践证明,通过该方法,很好地规范了空间数据生产和数据库建设,实现数据库建设整体质量控制,保证了数据质量。通过成果数据的应用效果分析,证实了该质量控制方法的有效性、实用性和可操作性,具有广泛的推广意义。     

Revisiting the Concentration Observations and Source Apportionment of Atmospheric Ammonia

<正>While China’s Air Pollution Prevention and Control Action Plan on particulate matter since 2013 has reduced sulfate significantly, aerosol ammonium nitrate remains high in East China. As the high nitrate abundances are strongly linked with ammonia, reducing ammonia emissions is becoming increasingly important to improve the air quality of China. Although satellite data provide evidence of substantial increases in atmospheric ammonia concentrations over major agricultural regions, long-t...     

欧盟空间信息基础设施建设(INSPIRE):兼议对中国地学信息化的启示

欧盟空间信息基础设施(INSPIRE)是欧洲空间信息基础设施建设法令。目的是建立欧盟统一的空间信息基础设施,实现有关环境空间信息在统一的框架下全欧盟范围内的共享,便于跨区域的政策决策及应用。通过近7年的实施,INSPIRE完成了欧盟层面的立法和各参与国层面具有法律效力的执行规则,制定了一系列技术规范和技术指南,并在各参与国中执行实施。总结分析欧盟空间信息基础设施(INSPIRE)的目的与意义、组织管理体系、实施方案、空间信息的融合与互操作、统一架构与相关规范等方面的相关经验,提出了对中国地学信息化的几点启示。     

吉南龙岗岩群四道砬子河岩组泥质片麻岩变质作用

吉南新太古代泥质片麻岩出露于龙岗岩群四道砬子河岩组中,本文通过系统的岩相学、矿物化学、激光拉曼和锆石U Pb同位素年代学等分析,研究其变质演化特点、变质作用时代及构造意义.结果表明:龙岗岩群四道砬子河岩组泥质片麻岩记录了３个变质演化阶段,其中峰前期进变质阶段(M１)的矿物组合为石榴石＋黑云母＋斜长石＋石英＋白云母;峰期变质阶段(M２)的矿物组合为石榴石＋矽线石＋钾长石＋黑云母＋斜长石＋石英,达到麻粒岩相;峰后期退变质阶段(M３)以矽线石转变为蓝晶石为特征标 志,矿物组合为蓝晶石＋石榴石＋黑云母＋斜长石＋石英＋白云母.变质矿物地质温压计限定其变质作用,峰前期(M１)T 为４６８~５１５ ℃,p 为(３．８~４．３)×１０５ kPa;峰期(M２)T 为７０３~７６０ ℃,p 为(６．６~７．１)×１０５kPa;峰后期(M３)T 为５５２~５９１℃,p 为(５．５~６．０)×１０５kPa;具有典型的近等压冷却型逆时针变质作用p T 演化轨迹特征,可能是在地幔柱与岩石圈相互作用的环境中变质作用与大量的幔源岩浆底侵作用有关.LA ICP MS锆石U Pb定年结果显示麻粒岩相变质作用时代为２４９５~２４４２Ma,属于新太古代变质热事件产物.     

黑龙江嫩江地区三合屯金矿区糜棱岩锆石LA-ICP-MS U-Pb年龄与成矿的关系

三合屯金矿位于黑龙江省嫩江县境内,普遍认为其是韧性剪切带型金矿.本次对采自韧性剪切带中花岗质糜棱岩样品进行了锆石LA-ICP-MS U-Pb定年,以约束剪切带的活动时代,并为金矿化事件提供依据,获得糜棱岩中热液锆石增生边加权平均年龄为162 Ma.因此,矿区在燕山期晚侏罗世经历剪切变形,并且这期变形事件与前人研究的科洛...     

Applicability of TRMM satellite precipitation in driving hydrological model for identifying flood events: a case study in the Xiangjiang River Basin,China

The spatial and temporal distribution of forest fires displays a complex pattern which strongly influences the forest landscape and the neighbouring anthropogenic development. Statistical methods developed for spatio-temporal stochastic point processes can be employed to find a structure, detect over-densities and trends in forest fire risk and address towards prevention and forecasting measures. The present study considers the Portuguese mapped burnt areas official geodatabase resulting from interpreted satellite measurements, covering the period 1990–2013. The main goal is to detect whether space and time act independently or whether, conversely, neighbouring events are also closer in time, interacting to generate clusters. To this purpose, the following statistical methods were applied: (1) the geographically weighted summary statistics, to explore how the average burned area vary locally through the investigated region; (2) the bivariate K-function, to test the space–time interaction and the spatial attraction/independency between fires of different size; and (3) the space–time kernel density, allowing elaborating smoothed density surfaces and representing over-densities of large versus medium versus small fires and on north versus south region. The proposed approach successfully allowed finding and mapping spatio-temporal patterns within this large data series. Specifically, medium fires tend to aggregate around small fires, while large fires aggregate at a larger distance and longer times, indicating that the return time following these events is longer than for small and medium fires. The density maps shows that hot spots are present almost each year in the northern region, with a higher concentration in the northern areas, while the southern half of the country counts lower surface densities of fires, which are mainly concentrated in the central period (2000–2007).     

Initiation and Development of the Late Cenozoic Uplift of Daluo Mountains, Northeastern Margin of the Tibetan Plateau

Daluo Mountains lie at front of the arcuate tectonic belt at the northeastern margin of the Tibetan Plateau, and are the landform boundary zone between the active Tibetan Plateau and the stable North China Craton. Studying of the late Cenozoic uplift evolution of Daluo Mountains is important for understanding the expansion mechanism of the northeastern margin of the Tibetan Plateau and its influence on the western North China Craton. In this study, the late Cenozoic uplift of Daluo Mountains is constructed from the development of the late Cenozoic alluvial fan around Daluo Mountains. The entire sedimentary sequence and framework of the fan was revealed by the newly obtained drilling core data. The cosmogenic nuclide, optically stimulated luminescence, and detrital zircon U-Pb dating results provide new evidences for discussion about the initial timing of the late Cenozoic uplift of Daluo Mountains and the key stages of uplift during the Pleistocene. The late Cenozoic alluvial fan at front of Daluo Mountains overlies a set of fluvial-facies strata; therefore, development of the alluvial-fan marks the start of late Cenozoic uplift of Daluo Mountains. The timing of this event can be constrained to ~4.64 Ma. Two extensive gravel layers (dated to ca. 0.76–0.6 Ma and ~0.05 Ma) developed during the Pleistocene, indicating two episodes of considerable uplift. This study provides a new time scale for the uplift and expansion of the arcuate tectonic belt at the northeastern margin of the Tibetan Plateau.     

Vibrational mode analysis and heat capacity calculation of K2SiSi3O9-wadeite

The phonon dispersions and vibrational density of state (VDoS) of the K₂SiSi₃O₉-wadeite (Wd) have been calculated by the first-principles method using density functional perturbation theory. The vibrational frequencies at the Brillouin zone center are in good correspondence with the Raman and infrared experimental data. The calculated VDoS was then used in conjunction with a quasi-harmonic approximation to compute the isobaric heat capacity (C _P ) and vibrational entropy ( $S_{298}^{0}$ ), yielding C _P (T) = 469.4(6) ? 2.90(2) × 10³  T ^?0.5 ? 9.5(2) × 10⁶  T ^?2 + 1.36(3) × 10⁹  T ^?3 for the T range of 298–1,000 K and $S_{298}^{0}$  = 250.4 J mol^?1 K^?1. In comparison, these thermodynamic properties were calculated by a second method, the classic Kieffer’s lattice vibrational model. On the basis of the vibrational mode analysis facilitated by the first-principles simulation result, we developed a new Kieffer’s model for the Wd phase. This new Kieffer’s model yielded C _P (T) = 475.9(6) ? 3.15(2) × 10³  T ^?0.5 – 8.8(2) × 10⁶  T ^?2 + 1.31(3) × 10⁹  T ^?3 for the T range of 298–1,000 K and $S_{298}^{0}$  = 249.5(40) J mol^?1 K^?1, which are in good agreement both with the results from our first method containing the component of the first-principles calculation and with some calorimetric measurements in the literature.