Solar rotation, 1966–1978

Photospheric and chromospheric spectroscopic Doppler rotation rates for the full solar disk are analyzed for the period July, 1966 to July, 1978. An approximately linear secular increase of the equatorial rate of 3.7% for these 12 years is found (in confirmation of Howard, 1976). The high latitude rates above 65 ° appear to vary with a peak-to-peak amplitude of 8%, or more, phased to the sunspot cycle such that the most rapid rotation occurs at, or following, solar maximum. The chromosphere, as indicated by H, has continued to rotate on the average 3% faster than the photosphere agreeing with past observations. Sources of error are discussed and evaluated.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.     

Elastic anisotropy of ferromagnesian post-perovskite in Earth's D” layer

We report experimental observation of a sizable elastic anisotropy in a polycrystalline sample of ferromagnesian silicate in post-perovskite (ppv) structure. Using a novel composite X-ray transparent gasket to contain and synthesize ppv in a panoramic diamond-anvil cell along with oblique X-ray diffraction geometry, we observed the anisotropic lattice strain and {1 0 0} or {1 1 0} slip-plane texture in the sample at 140 GPa. We deduced the elasticity tensor (c_ij), orientation-dependent compressional wave velocities, polarization-dependent shear-wave velocities, and the velocity anisotropy of the silicate ppv. Our results are consistent with calculations and indicate that with sufficient preferred orientation, the elastic anisotropy of this phase can produce large shear-wave splitting.     

Sea‐level and ocean‐current control on carbonate‐platform growth,Maldives, Indian Ocean

Multichannel high‐resolution seismic and multibeam data were acquired from the Maldives‐isolated carbonate platform in the Indian Ocean for a detailed characterization of the Neogene bank architecture of this edifice. The goal of the research is to decipher the controlling factors of platform evolution, with a special emphasis on sea‐level changes and changes of the oceanic currents. The stacking pattern of Lower to Middle Miocene depositional sequences, with an evolution of a ramp geometry to a flat‐topped platform, reflects variations of accommodation, which here are proposed to be primarily governed by fluctuations of relative sea level. Easterly currents during this stage of bank growth controlled an asymmetric east‐directed progradation of the bank edge. During the late middle Miocene, this system was replaced by a twofold configuration of bank development. Bank growth continued synchronously with partial bank demise and associated sediment‐drift deposition. This turnover is attributed to the onset and/or intensification of the Indian monsoon and related upwelling and occurrence of currents, locally changing environmental conditions and impinging upon the carbonate system. Mega spill over lobes, shaped by reversing currents, formed as large‐scale prograding complexes, which have previously been interpreted as deposits formed during a forced regression. On a regional scale, a complex carbonate‐platform growth can occur, with a coexistence of bank‐margin progradation and aggradation, as well as partial drowning. It is further shown that a downward shift of clinoforms and offlapping geometries in carbonate platforms are not necessarily indicative for a sea‐level driven forced regression. Findings are expected to be applicable to other examples of Cenozoic platforms in the Indo‐Pacific region.     

Airborne gravimetry used in precise geoid computations by ring integration

Two detailed geoids have been computed in the region of North Jutland. The first computation used marine data in the offshore areas. For the second computation the marine data set was replaced by the sparser airborne gravity data resulting from the AGMASCO campaign of September 1996. The results of comparisons of the geoid heights at on-shore geometric control showed that the geoid heights computed from the airborne gravity data matched in precision those computed using the marine data, supporting the view that airborne techniques have enormous potential for mapping those unsurveyed areas between the land-based data and the off-shore marine or altimetrically derived data. Received: 7 July 1997 / Accepted: 22 April 1998     

军民测绘标准融合方法研究

为了统筹军地资源,加强国防建设和经济建设,国家对军民融合的发展战略进行了统一部署。军民测绘标准融合是推动军民测绘事业发展的一项重要内容。通过梳理和对比分析现有军民测绘标准体系及其标准之间的相互关系,提出军民测绘标准融合的工作建议,从而为军民测绘标准融合工作的开展与实施提供参考。     

Earth Observation Scientific Workflows in a Distributed Computing Environment

Geospatially Enabled Scientific Workflows offer a promising toolset to help researchers in the earth observation domain with many aspects of the scientific process. One such aspect is that of access to distributed earth observation data and computing resources. Earth observation research often utilizes large datasets requiring extensive CPU and memory resources in their processing. These resource intensive processes can be chained; the sequence of processes (and their provenance) makes up a scientific workflow. Despite the exponential growth in capacity of desktop computers, their resources are often insufficient for the scientific workflow processing tasks at hand. By integrating distributed computing capabilities into a geospatially enabled scientific workflow environment, it is possible to provide researchers with a mechanism to overcome the limitations of the desktop computer. Most of the effort on extending scientific workflows with distributed computing capabilities has focused on the web services approach, as exemplified by the OGC's Web Processing Service and by GRID computing. The approach to leveraging distributed computing resources described in this article uses instead remote objects via RPyC and the dynamic properties of the Python programming language. The Vistrails environment has been extended to allow for geospatial processing through the EO4Vistrails package ( http://code.google.com/p/eo4vistrails/ ). In order to allow these geospatial processes to be seamlessly executed on distributed resources such as cloud computing nodes, the Vistrails environment has been extended with both multi‐tasking capabilities and distributed processing capabilities. The multi‐tasking capabilities are required in order to allow Vistrails to run side‐by‐side processes, a capability it does not currently have. The distributed processing capabilities are achieved through the use of remote objects and mobile code through RPyC.     

数字城市“十分钟健身圈”示范应用系统研究与开发

数字城市建设既是加快城市现代化的内在要求,也是增强城市综合竞争力的有力工具。天地图各项工作的推进,加快了数字城市的发展,随着全民健身越来越受重视,体育健身信息与基础地理信息相结合的体育信息系统应运而生,本文基于"天地图.江苏"公共服务平台,完成了数字城市"十分钟健身圈"示范应用系统的架构以及系统主要功能的设计,采用B/S与C/S相结合的方式,实现了集电子地图和体育专题数据为一体的"十分钟健身圈"应用示范系统。     

基于 Gamit 解算的 NNCORS 站点CGCS2000坐标的确定方法

本文以南宁市NNCORS站点为例,介绍了基于GAMIT的基线平差法和框架转换法求解NNCORS站点的CGCS2000坐标,分析了两种方法的求解精度,并对两种解算结果进行比较,为城市CORS站点CGCS2000坐标确定提供参考。     

A Composite Semisupervised SVM for Classification of Hyperspectral Images

This letter presents a novel composite semisupervised support vector machine (SVM) for the spectral-spatial classification of hyperspectral images. In particular, the proposed technique exploits the following: 1) unlabeled data for increasing the reliability of the training phase when few training samples are available and 2) composite kernel functions for simultaneously taking into account spectral and spatial information included in the considered image. Experiments carried out on a hyperspectral image pointed out the effectiveness of the presented technique, which resulted in a significant increase of the classification accuracy with respect to both supervised SVMs and progressive semisupervised SVMs with single kernels, as well as supervised SVMs with composite kernels.