Wave propagation within random packings of spheres     

K. Walton 《Geophysical Journal International》1988,92(1):89-97

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A dislocation model for the earthquake cycle at convergent plate boundaries   总被引：1，自引：0，他引：1  

Mitsuhiro Matsu'ura  Toshinori Sato 《Geophysical Journal International》1989,96(1):23-32

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嵌入式GIS的三维地形显示算法研究   总被引：1，自引：1，他引：0  

范丹丹  金梁  陈明 《测绘科学》2006,31(6):158-159

本文论述了基于嵌入式G IS的三维地形显示的一系列理论和算法。首先介绍了三维地形显示的基本算法步骤,接下来针对嵌入式系统的特点,提出了三个改进方面,分别是递归细分、坐标变换和内存调度。在论文的最后,给出了实验结果并进行了总结。  相似文献   

中国海岸带专用地图投影设计   总被引：3，自引：0，他引：3  

韩雪培  李满春  傅小毛 《测绘学报》2006,35(4):395-399

地图投影是各类海岸带信息的空间定位框架要素之一。通过对目前我国海岸带常用的各种地图投影现状分析,设计并实现全国海岸带专用投影———斜轴等角圆锥投影,该投影不仅使得整个中国海岸带实现无缝的一体化表达,而且使变形达到最小。文中详细阐述该投影的设计思想和设计原理,并将结果与其他各种海岸带投影进行详细的分析比较。  相似文献   

南大洋海冰影像地图投影变换与瓦片切割应用研究          下载免费PDF全文

田璐艾松涛  鄂栋臣龚洪清 沈权徐宁  张宏洋 《极地研究》2012,24(3):284-290

南大洋海冰分布是南极考察过程中影响破冰船航行的重要因素,也是南极研究的重要内容之一。目前国际上不同机构发布的南大洋海冰分布图,大多是球面投影,不能直接用于主流的瓦片地图发布。将极方位立体投影海冰图转换为目前主流的网络墨卡托投影地图,并利用合适的图像重采样方法,按照不同级别比例尺进行瓦片切割和编号存储,最终实现海冰影像地图的发布共享是本文的主要研究内容。笔者对不同的图像重采样方法进行了比较,分析了最邻近点采样方法、双线性内插和双三次卷积重采样方法的优劣,针对本文的研究优选双线性内插方法进行影像地图瓦片的切割,并最终叠加融合在Google地图上,实现了Google底图、准实时海冰影像图与破冰船走航位置的集成显示,为雪龙船的冰区航行提供了重要的数据支撑。  相似文献   

Snow water equivalent over Eurasia in the next 50 years projected by aggregated CMIP3 models     

LiJuan M  Yong Luo  DaHe Qin 《寒旱区科学》2012,4(2):0093-0106

Based on remote sensing snow water equivalent (SWE) data, the simulated SWE in 20C3M experiments from 14 models attending the third phase of the Coupled Models for Inter-comparison Project (CMIP3) was first evaluated by computing the different percentage, spatial correlation coefficient, and standard deviation of biases during 1979–2000. Then, the diagnosed ten models that performed better simulation in Eurasian SWE were aggregated by arithmetic mean to project the changes of Eurasian SWE in 2002–2060. Results show that SWE will decrease significantly for Eurasia as a whole in the next 50 years. Spatially, significant decreasing trends dominate Eurasia except for significant increase in the northeastern part. Seasonally, decreasing proportion will be greatest in summer indicating that snow cover in warmer seasons is more sensitive to climate warming. However, absolute decreasing trends are not the greatest in winter, but in spring. This is caused by the greater magnitude of negative trends, but smaller positive trends in spring than in winter. The changing characteristics of increasing in eastern Eurasia and decreasing in western Eurasia and over the Qinghai-Tibetan Plateau favor the viewpoint that there will be more rainfall in North China and less in the middle and lower reaches of the Yangtze River in summer. Additionally, the decreasing rate and extent with significant decreasing trends under SRES A2 are greater than those under SRES B1, indicating that the emission of greenhouse gases (GHG) will speed up the decreasing rate of snow cover both temporally and spatially. It is crucial to control the discharge of GHG emissions for mitigating the disappearance of snow cover over Eurasia.  相似文献   

Monsoon Change in East Asia in the 21st Century: Results of RegCM3          下载免费PDF全文

SUI Yue  LANG Xian-Mei 《大气和海洋科学快报》2012,5(6):504-508

The authors investigate monsoon change in East Asia in the 21st century under the Special Report on Emissions Scenarios (SRES) A1B scenario using the results of a regional climate model, RegCM3, with a high horizontal resolution. First, the authors evaluate the model’s performance compared with NCEP-NCAR reanalysis data, showing that the model can reliably reproduce the basic climatology of both winter and summer monsoons over East Asia. Next, it is found that the winter monsoon in East Asia would slightly weaken in the 21st century with spatial differences. Over northern East China, anomalous southerly winds would dominate in the mid-and late-21st century because the zonal land-sea thermal contrast is expected to become smaller, due to a stronger warming trend over land than over ocean. However, the intensity of the summer monsoon in East Asia shows a statistically significant upward trend over this century because the zonal land-sea thermal contrast between East Asia and the western North Pacific would become larger, which, in turn, would lead to larger sea level pressure gradients throughout East Asia and extending to the adjacent ocean.  相似文献   

花土沟地区GPS网工程测量投影面的选择     

康英平 《东北测绘》2012,(2):176-177

首先介绍了工程测量投影面选择时应该考虑的一些基本概念性内容,然后以柴达木盆地花土沟地区GPS工程控制网投影面的选择和计算过程为例,得到一些有用结论。  相似文献   

几内亚BOKE558铝土矿勘探独立坐标系的建立及转换研究     

兰进京  孙清娟 《东北测绘》2012,(3):196-198

建立地方独立坐标系的主要元素是中央子午线、投影面和参考椭球。建立独立坐标系有三种方法：中央子午线移到城市或工程建设地区中央,归化高程面提高到该地区的平均高程面;采用抵偿高程面;只移动中央子午线。以工程实例得出国家坐标系与地方独立坐标系之间转换的可靠、简便方法。  相似文献   

南京长江第四大桥索夹的定位测量     

李支彬  黄腾  康建松  刘岭 《测绘工程》2012,21(5):53-55

以南京长江第四大桥索夹放样为例,介绍该桥索夹位置计算和测量放样的基本方法和流程。分析影响悬索桥索夹放样精度的因素,并加以修正或消除,用以提高索夹放样精度。实践证明本桥索夹放样方法简单、可靠,满足设计要求。  相似文献