冰川均衡调整对南极冰质量平衡监测的影响及其不确定性

本文研究了新的全球冰川均衡调整(GIA)模型对南极冰盖质量平衡监测的影响,考虑现有冰川负荷模型和地幔黏滞度模型的差异,完整评估了结果的不确定性,最后结合GRACE和卫星测高的结果进行了对比分析.结果表明,GIA对GRACE监测的等效水柱变化有重大影响,较大的GIA影响出现在西南极,沿罗斯冰架-卡姆布冰流-罗尼冰架-南极...     

中国区域治理中公私合作伙伴关系研究

以新国家空间理论视角阐释中国区域治理中公私合作伙伴关系的产生逻辑和运行机制。本文认为建构公私合作伙伴关系旨在空间修复发展资源分配不均、经济发展失衡和政府管制失灵。首先,中央政府根据行政等级、职能和区划来调整多层级政府权力关系,并依据企业产权属性推进政府和市场权力再分配以修复治理困境。其次,中央政府以行政激励促进公私合作,达成区域整体利益最优并构建资源分配秩序。同时,地方政府联盟以辖区利益最大化为导向,推动中央政府和社会资本融入地方治理。最后,多层级政府以行政命令界定公私部门责任边界,或构建公共服务体系来解决市场失灵。中国区域治理不仅是国家权力跨尺度重构以实现国家管制,也是以跨越公私边界的权力、责任与利益的相互作用构建新的区域治理体制。     

The observation of extensive air showers from an Earth-orbiting satellite

We review the main issues that are relevant for the observation of extensive air showers from an Earth-orbiting satellite. Extensive air showers are produced by the interaction of ultra-high energy cosmic particles with the atmosphere and can be observed by an orbiting telescope detecting the air scintillation light.We provide the main analytical formulas and semi-analytical results needed to optimize the design of a suitable telescope and estimate the best-expected performance and the minimal necessary requirements for the observation.While we have in mind an EUSO-like general-purpose experiment, the results presented in this paper are useful for any kind of space-based experiment.     

地震前后遥感影像空间尺度特性与最优空间尺度选择

本文基于不同计算窗口大小的改进局部方差方法, 判定地震后遥感影像上的目标物, 如损毁建筑物、 完好建筑物的最佳空间尺度。 对航片、 QuickBird影像进行了系列实验分析, 得到了在QuickBird影像中城区完好建筑物最佳空间分辨率在2~3 m, 损毁建筑物最佳空间分辨率2~4 m, 航片中城区完好建筑物最佳空间分辨率为3~4 m。 最佳空间分辨率与目标地物的尺度紧密相关, 不同尺度大小的地物具有不同的最优空间尺度。 最佳空间尺度的选择在处理海量高空间分辨率影像时通过重采样选取最佳空间分辨率, 可以有效减少图像运算时间, 在地震灾害快速评估中具有一定的应用意义。     

跨国公司研发全球化的空间等级体系研究——基于因子分析的结果

在公司区位选择研究的基础上探索跨国公司研发全球化的空间等级体系,是地理学对跨国公司研发全球化研究的有益尝试。跨国公司研发全球化是多种因素协同互动的结果,为了相对科学直观地构建跨国公司全球研发空间等级体系,本文运用因子分析方法对84个样本进行研究表明。跨国公司全球研发网络是多种因素协同互动的结果,综合实力、研发环境、市场规模是其中最重要的区位因子。根据因子分析的综合得分,将跨国公司研发全球化的空间等级分为五个层次,即核心区域、高密区域、中密区域、低密区域和弱势区域。发达国家明显占据全球研发空间体系的主导地位,掌控着科技发展前沿和关键核心技术,但个别发展中国家和地区也已进入较高层次。根据各主因子的得分情况．按照在全球位势强弱和要素空间流向的不同,把全球国家（地区）分为全面发展型、环境优势型和市场潜力型三种类型。其中,中国位列跨国公司研发全球化的高密区域,但仍属市场潜力型国家,处于接受扩散的境地。基础研究和创新能力薄弱以及内外向流动的不均衡,阻碍了跨国公司全球研发空间体系节点区域的创建。     

Mars Express and Venus Express multi-point observations of geoeffective solar flare events in December 2006

In December 2006, a single active region produced a series of proton solar flares, with X-ray class up to the X9.0 level, starting on 5 December 2006 at 10:35 UT. A feature of this X9.0 flare is that associated MeV particles were observed at Venus and Mars by Venus Express (VEX) and Mars Express (MEX), which were ∼80° and ∼125° east of the flare site, respectively, in addition to the Earth, which was ∼79° west of the flare site. On December 5, 2006, the plasma instruments ASPERA-3 and ASPERA-4 on board MEX and VEX detected a large enhancement in their respective background count levels. This is a typical signature of solar energetic particle (SEP) events, i.e., intensive MeV particle fluxes. The timings of these enhancements were consistent with the estimated field-aligned travel time of particles associated with the X9.0 flare that followed the Parker spiral to reach Venus and Mars. Coronal mass ejection (CME) signatures that might be related to the proton flare were twice identified at Venus within <43 and <67 h after the flare. Although these CMEs did not necessarily originate from the X9.0 flare on December 5, 2006, they most likely originated from the same active region because these characteristics are very similar to flare-associated CMEs observed on the Earth. These observations indicate that CME and flare activities on the invisible side of the Sun may affect terrestrial space weather as a result of traveling more than 90° in both azimuthal directions in the heliosphere. We would also like to emphasize that during the SEP activity, MEX data indicate an approximately one-order of magnitude enhancement in the heavy ion outflow flux from the Martian atmosphere. This is the first observation of the increase of escaping ion flux from Martian atmosphere during an intensive SEP event. This suggests that the solar EUV flux levels significantly affect the atmospheric loss from unmagnetized planets.     

Characterization of the Meteoroid Spatial Flux Density during the 1999 Leonid Storm

The November 18, 1999 Leonid storm was rich in meteors and well observed by airborne intensified video cameras aimed low in the sky which enabled enhanced meteor counts over ground-based observations. The two- and three-dimensional distribution of meteoroids was investigated for signs of clustering that could provide evidence of meteoroid fragmentation shortly after lift-off from the parent comet 55P/Tempel-Tuttle, or much later due to space weathering. Analysis of the video tapes yields a refined estimation of the mass ratio during the peak of s = 1.65 and spatial flux density of 0.5 particles/km² greater than those causing visual magnitude +6.5 during the 5 min centered around the peak of the storm. Furthermore, the projection of the individual trails into three-dimensional Heliocentric coordinates, shows non-homogeneity of the stream on spatial scales from hundreds to thousands of kilometers.     

NEOCAM: The Near Earth Object Chemical Analysis Mission

The prime measurement objective of the Near Earth Object Chemical Analysis Mission (NEOCAM) is to obtain the ultraviolet spectra of meteors entering the terrestrial atmosphere from ∼125 to 300 nm in meteor showers. All of the spectra will be collected using a slitless ultraviolet spectrometer in Earth orbit. Analysis of these spectra will reveal the degree of chemical diversity in the meteors, as observed in a single meteor shower. Such meteors are traceable to a specific parent body and we know exactly when the meteoroids in a particular shower were released from that parent body (Asher, in: Arlt (ed.) Proc. International Meteor Conference, 2000; Lyytinen and van Flandern, Earth Moon Planets 82–83:149–166, 2000). By observing multiple apparitions of meteor showers we can therefore obtain quasi-stratigraphic information on an individual comet or asteroid. We might also be able to measure systematic effects of chemical weathering in meteoroids from specific parent bodies by looking for correlations in the depletions of the more volatile elements as a function of space exposure (Borovička et al., Icarus 174:15–30, 2005). By observing the relation between meteor entry characteristics (such as the rate of deceleration or breakup) and chemistry we can determine if our meteorite collection is deficient in the most volatile-rich samples. Finally, we can obtain a direct measurement of metal deposition into the terrestrial stratosphere that may act to catalyze atmospheric chemical reactions.