����GPS���ߵ����������о���ǰ������쳣

????COSMIC??????????????????????о???2006??11??15????????Ms8.0?????2007??2??25????????Ms5.3??????????????????????????????仯,?????K???(???)?????????????????仯??????????????? ?о????????GPS???????????????????????????????????????????????仯,?????仯???п????????????????     

������С���˷�������ά����ת���е�Ӧ��

????о???????С???????????С????????????С????????????????е???????????????????????????????У??????????????????μ?????????????????????????????????С???????????????е????????A??????????b??????????????????????????????????????????LS????????????????С??????????????????????????????????     

Gas hydrates in the western deep-water Ulleung Basin, East Sea of Korea

Geophysical surveys and geological studies of gas hydrates in the western deep-water Ulleung Basin of the East Sea off the east coast of Korea have been carried out by the Korea Institute of Geoscience and Mineral Resources (KIGAM) since 2000. The work included a grid of 4782 km of 2D multi-channel seismic reflection lines and 11 piston cores 5–8 m long. In the piston cores, cracks generally parallel to bedding suggest significant in-situ gas. The cores showed high amounts of total organic carbon (TOC), and from the southern study area showed high residual hydrocarbon gas concentrations. The lack of higher hydrocarbons and the carbon isotope ratios indicate that the methane is primarily biogenic. The seismic data show areas of bottom-simulating reflectors (BSRs) that are associated with gas hydrates and underlying free gas. An important observation is the numerous seismic blanking zones up to 2 km across that probably reflect widespread fluid and gas venting and that are inferred to contain substantial gas hydrate. Some of the important results are: (1) BSRs are widespread, although most have low amplitudes; (2) increased P-wave velocities above some BSRs suggest distributed low to moderate concentration gas hydrate whereas a velocity decrease below the BSR suggests free gas; (3) the blanking zones are often associated with upbowing of sedimentary bedding reflectors in time sections that has been interpreted at least in part due to velocity pull-up produced by high-velocity gas hydrate. High gas hydrate concentrations are also inferred in several examples where high interval velocities are resolved within the blanking zones. Recently, gas hydrate recoveries by the piston coring and deep-drilling in 2007 support the interpretation of substantial gas hydrate in many of these structures.     

混合稀疏表示模型的超分辨率重建

超分辨率重建是当前卫星遥感数据空间分辨率提升的重要技术，但目前现有的超分辨率重建方法在处理具有复杂地物特征的影像时效果往往不佳。当遥感影像中包含有各种非均匀地物信息时，难以构建一种通用的模型来解决遥感影像的病态问题。基于此，本文结合图像稀疏表达与非凸高阶全变分理论，提出了一种混合稀疏表示模型的新型超分辨率重建方法（MSR-SRR）。这种方法以遥感图像在多重变换域的稀疏性表达作为先验概率模型，通过正则化方法来完成超分辨率重构，不仅保留了超分重建结果影像的边缘信息，而且对影像中产生的“阶梯效应”进行了适当的平滑处理。该方法利用迭代重加权l1交替方向乘子方法进行求解，提高了算法的运行效率，改善了影像质量。为了证明所提出方法的有效性，MSR-SRR结果与非均匀插值、POCS和IBP等传统超分方法的重建结果进行了对比验证。结果表明，MSR-SRR方法的图像清晰度平均提升了31.74%，PSFs半峰宽度最大，高斯方差值达到1.8415，效果明显优于其他方法。为进一步评估MSR-SRR结果的实用性，本文以高分四号卫星（GF-4）影像作为样例，利用支持向量机（SVM）分类方法对超分重建前后的影像进行了分类试验和精度验证。结果表明，超分辨率重建后的影像结果相对于原始影像的分类结果，Kappa系数提升了9.7%，OA值提升了5.96%。这表明MSR-SRR方法可以有效提升影像清晰度，丰富影像纹理细节，增强图像质量，有效提升影像分类精度。     

基于CloudSat卫星对地基云雷达反射率因子的校准

地基云雷达是云的重要探测手段，但随着运行时间的增加，雷达发射机、接收器等参数的变化，会使观测数据产生漂移偏差，从而对云物理特性的反演产生显著影响，因此云雷达数据的校准是一个重要的基础问题。针对KAZR（Ka Band Zenith Radar，K波段云雷达）云雷达特征，本文在Pavlos等提出的雷达数据校准方法基础上进行改进，优化了对弱云和降水的信号识别，利用CloudSat星载雷达观测的反射率因子，气体衰减校正等数据，对兰州大学半干旱气候环境监测站（Semi Arid Climate and Environment Observatory of Lanzhou University，SACOL）KAZR云雷达2013年8月至2017年5月反射率因子数据进行了校准，建立了KAZR雷达反射率因子46个月的历史资料校准数据库，并对校准周期的变化进行了对比分析。校准数据库的建立对SACOL站云的长期观测研究具有重要意义，同时为不同波段地基雷达的对比增加了可行性。