浅水多波束测深资料处理关键技术探讨

为提高浅水多波束测深资料处理成果质量,基于澳门海域浅水多波束测深资料,提出应用POS/MV大地高数据计算实时潮汐数据,探讨了浅水多波束测深资料声速校正方法.结果 表明,经过潮汐改正和声速改正后资料处理成果质量明显提高,解决了浅水多波束测深资料处理中的难题,本方法可为浅水多波束测深资料处理提供重要指导.     

LURR's Twenty Years and its Perspective

Seismogenic process is a nonlinear and irreversible one, so that the response to loading of a seismogenic zone is different from the unloading one. This difference reflects quantitatively the process of an earthquake preparation. A physics-based new parameter-Load/Unload Response Ratio (LURR) was proposed to measure quantitatively the proximity to a strong earthquake and then used to be an earthquake predictor. In the present paper, a brief history of LURR is recalled; inspection of real earthquake cases, numerical simulations and laboratory studies of LURR, prediction efforts in terms of LURR, probability problem of LURR and its prospect are also expatiated.     

Spatial and Temporal Variation of LURR and its Implication for the Tendency of Earthquake Occurrence in Southern California

— Based on the theory of LURR and its recent development, spatial and temporal variation of Y/Y _c (value of LURR/critical value of LURR) in the Southern California region during the period from 1980 through March, 2001 was studied. According to the previous study on the fault system and stress field in Southern California, we zoned the Southern California region into 11 parts in each of which the stress field is almost uniform. With the time window of one year, time moving step of three months, space window of a circle region with a radius of 100 km and space moving step of 0.25 degree in latitude and longitude direction, the evolution of Y/Y _c were snapshot. The scanning results show that obvious Y/Y _c anomalies occurred before 5/6 of strong earthquakes considered with a magnitude of 6.5 or greater. The critical regions of Y/Y _c are near the epicenters of the strong earthquakes and the Y/Y _c anomalies occur months to years prior to the earthquakes. The tendency of earthquake occurrence in the California region is briefly discussed on the basis of the examination of Y/Y _c .     

多波束海底地形图的制作方法探讨

提出了采用高斯距离函数加权平均算法,对离散多波束数据进行网格化,该算法的优点是权函数收敛较快,能较好地保留细小的地形特征,而且运算速度较快。对于图形制作方面,提出了2D等深线图叠加3D阴影图模式的海底地形图的绘制思路及实现方法,最终成果图立体感强,可以更好地表现出地形细节。最后就如何改进海底地形图的配色方案进行了探讨。     

Anthropogenic hillslope terraces and swidden agriculture in Jiuzhaigou National Park, northern Sichuan, China

Small, irregular terraces on hillslopes, or terracettes, are common landscape features throughout west central China. Despite their prevalence, there is limited understanding of the nature of these topographic features, the processes that form them, and the role humans played in their formation. We used an interdisciplinary approach to investigate the geology, ecology, and cultural history of terracette development within Jiuzhaigou National Park, Sichuan Province, China. Terracettes occur on south facing, 20° slopes at 2500 m elevation, which appears to coincide with places people historically preferred to build villages. Ethnographic interviews suggest that traditional swidden agricultural cycles removed tree roots, causing the loess sediments to lose cohesion, slump, and the terrace risers to retreat uphill over time. This evidence is supported by landslide debris at terracette faces. Archaeological analysis of terracette sites reveal remains of rammed spread soil structures, bones, stone tools, and ceramics dating from at least 2200 years before present within a distinct paleosol layer. Radiocarbon and optically stimulated luminescence dating of terracette sediments ranged in age from between 1500 and 2000 ¹⁴C yr BP and between 16 and 0.30 ka, respectively. These multiple lines of evidence indicate a long history of human habitation within Jiuzhaigou National Park and, taken together, suggest strong links between terracette formation and human-landuse interactions.     

一种基于AMSR-E的地表温度半经验反演模型

基于被动微波辐射传输方程,结合De Jeu建立的透过率与微波极化差异指数的通用关系式,以及Smiths建立的地表温度与大气总可降水量的经验关系,构建了一套基于AMSR-E影像的地表温度半经验反演模型,该模型无需借助其他辅助数据,便可从AMSR-E 6.9GHz和10.7GHz两个波段的亮度温度模拟得到地表温度变量。对2009年我国地表温度进行实例模拟和验证,结果显示,该地表温度模型的平均反演精度达到2.54℃（R2=0.79）,是一种简单有效的被动微波遥感地表温度模拟方法。     

1988―2006年珠三角建设用地扩展的空间差异分析

采用珠三角1988、1998、2006年3个时相的建设用地解译数据,借助GIS空间分析工具,采用空间重心分析、象限缓冲区分析、典型区位空间分析、景观形态分析等空间分析方法,对1988年以来珠三角建设用地扩展的空间特征进行研究。其结果表明:1988年以来,珠三角的建设用地进入高速扩展时期,建设用地空间重心总体向东南方向移动,整个区域东部及南部的建设用地扩展占绝对优势,特别在近珠江口以及珠江口东岸地区表现得更加明显,围绕珠江口形成"剧烈扩展型―强扩展型―弱扩展型―稳定型"递变圈层结构;建设用地总体上呈现向沿路、沿海和平原区等典型区位集聚的特征,但在斑块层面上则表现出形态复杂和布局散乱的特点,且围绕城市中心区形成"集聚(高水平)―分散―集聚(低水平)"的圈层递变结构。     

Investigation of the Macroscopic Anomalies before and after the M8. 0 Wenchuan Earthquake

The macroscopic anomalies before and after the May 12,2008 Wenchuan M8. 0 earthquake were collected and analyzed in this paper. The credible anomalies occurring from February 1 to June 10,2008 were treated as macroscopic anomalies,and their space-time distribution was studied. The research indicates that in time distribution, the number of macroscopic anomalies peaked before the earthquake, and these peak values appeared twice after the earthquake. In space distribution, the distribution of macroscopic anomalies before the earthquake was the same as that after the earthquake. In this paper, the mechanism of occurrence of macroscopic anomalies and the role of macroscopic anomalies in forecasting earthquake were also discussed.