Mantle heat flow and thermal structure of the northern block of Southern Granulite Terrain, India   总被引：1，自引：0，他引：1  

Ajay Manglik   《Journal of Geodynamics》2006,41(5):510-519

Continental shield regions are normally characterized by low-to-moderate mantle heat flow. Archaean Dharwar craton of the Indian continental shield also follows the similar global pattern. However, some recent studies have inferred significantly higher mantle heat flow for the Proterozoic northern block of Southern Granulite Terrain (SGT) in the immediate vicinity of the Dharwar craton by assuming that the radiogenic elements depleted exposed granulites constitute the 45-km-thick crust. In this study, we use four-layered model of the crustal structure revealed by integrated geophysical studies along a geo-transect in this region to estimate the mantle heat flow. The results indicate that: (i) the mantle heat flow of the northern block of SGT is 17 ± 2 mW/m², supporting the global pattern, and (ii) the lateral variability of 10–12 mW/m² in the surface heat flow within the block is of crustal origin. In terms of temperature, the Moho beneath the eastern Salem–Namakkal region appears to be at 80–100 °C higher temperature than that beneath the western Avinashi region.  相似文献   

鲁中山区地形对山东省一次暴雨影响的敏感性数值模拟试验   总被引：3，自引：0，他引：3  

张可欣  汤剑平  邰庆国  裴洪芹 《气象科学》2007,27(5):510-514

利用PSU/NCAR MM5V3中尺度数值模式进行了鲁中山区地形对一次台风暴雨的数值模拟敏感性试验,结果分析表明:鲁中山区地形作用对山东省暴雨有重要影响,迎风坡可引起低层气流和水汽的辐合上升运动增强,降水量增加,但偏北气流在迎风坡的水汽辐合不明显,降水量影响不大;山顶引起低层辐合上升运动减弱,辐散下沉运动增强,降水量减小;背风坡引起低层气流和水汽的辐合上升运动增强,降水量增加。  相似文献   

伴随同化系统中用云导风修正模式地形的试验   总被引：1，自引：0，他引：1  

何芬  沈桐立  贺哲  赖绍钧  马镜娴 《高原气象》2007,26(2):300-308

以2002年7月23日的天气过程为例,利用中尺度模式MM5伴随模式同化系统,进行了修正模式地形高度的试验研究。结果发现,MM5伴随模式同化系统可以对地形进行修正,并得到与资料更为协调一致的地形高度。另外,利用非常规云导风资料能够比仅使用常规资料更有效地修正模式地形高度。将修正后的地形场作为模式地形,所得的预报结果比未经修正的地形有所改进。  相似文献   

一种基于点云提取微地形对象的方法     

石志宽  ;符海月 《测绘软科学研究》2009,(1):32-37

在分析微地形特点以及现有网格DEM在表述微地形中存在的不足的基础上，提出了面向对象的数字高程模型，给出了该模型的形式化描述和以点云为数据源构建面向对象数字高程模型过程中采用的对象边界的识别、特征保持的点云疏化、基于属性近似的网格约化及对象识别等关键步骤的方法。并以实例证明了此过程的可行性。  相似文献   

Skyline精细地形场景生成探讨   总被引：1，自引：0，他引：1  

徐占华  梁建国  李响 《北京测绘》2009,(1)

提出了Skyline精细地形场景生成的解决方案,并针对业务思路、业务流程进行了详细介绍,同时,通过实例说明方案的可行性,为工作开展提供了便利。  相似文献   

The mafic–ultramafic complex of Aniyapuram,Cauvery Suture Zone,southern India: Petrological and geochemical constraints for Neoarchean suprasubduction zone tectonics     

《Journal of Asian Earth Sciences》2014

Several Precambrian mafic–ultramafic complexes occur along the Cauvery Suture Zone (CSZ) in Southern Granulite Terrain, India. Their origin, magmatic evolution and relationship with the associated high-grade rocks have not been resolved. The Aniyapuram Mafic–Ultramafic Complex (AMUC), the focus of the present study in southern part of the CSZ, is dominantly composed of peridotites, pyroxenites, gabbros, metagabbros/mafic granulites, hornblendites, amphibolites, plagiogranites, felsic granulites and ferruginous cherts. The rock types in the AMUC are structurally emplaced within hornblende gneiss (TTG) basement rocks and are highly deformed. The geochemical signature of the amphibolites indicates tholeiitic affinity for the protolith with magma generation in island arc-setting. N-MORB normalized pattern of the amphibolites show depletion in HFS-elements (P, Zr, Sm, Ti, and Y) and enrichment of LIL-elements (Rb, Ba, Th, Sr) with negative Nb anomalies suggesting involvement of subduction component in the depleted mantle source and formation in a supra-subduction zone tectonic setting. Our new results when correlated with the available age data suggest that the lithological association of AMUC represent the remnants of the Neoarchean oceanic lithosphere.  相似文献   

Terrain Pattern Recognition and Spatial Decision Making for Regional Slope Stability Studies   总被引：1，自引：0，他引：1  

George?MiliaresisEmail author  Nikos?Sabatakakis  George?Koukis 《Natural Resources Research》2005,14(2):91-100

A terrain partition scheme is presented that allows the identification of regions with high landslide risk in natural terrain zones on the basis of geomorphometric criteria from moderate resolution DEMs. The key factor being the terrain segmentation to aspect regions (regions formed by points preserving the same aspect direction) instead of using an artificial regular-grid terrain partition scheme. The study area is in western Greece (NW Peloponnesus) whereas a moderate resolution digital elevation model with spacing 75 m is used. Landslide inventory analysis and knowledge conceptualization identified that the landslide susceptibility of a particular aspect region is high, if the mean elevation is low and the mean gradient is high. Each aspect region was parametrically represented on the basis of its mean gradient and elevation. The domain of each parameter was divided to seven slices (classes) on the basis of the observed density. Subsequent knowledge based mapping identified aspect regions with high landslide susceptibility for the following spatial rule: (a) “mean slope in class 6 or 7” and (b) “mean elevation in class 1 to 5”. Alternatively the rule is expressed as mean slope to be equal or greater than 15^∘ whereas mean elevation to be in the range 0 to 750 m. These identified zones correspond to regions where historical landslides occurred (populated coastal areas in the North) as well as to south regions (natural terrain zone) where no landslide record is available, because of the limitations posed by the natural terrain landslide mapping program in Greece. The presented terrain segmentation technique combined to the spatial decision-making process, provided both an object framework for integrating geomorphometric parameters and a method for landslide risk analysis in natural terrain zones.  相似文献   

DEM与地形分析的并行计算     

宋效东  刘学军  汤国安  王永君  田剑  窦万峰 《地理与地理信息科学》2012,28(4):1-7

总结了数字高程模型构建、特征提取等并行算法的研究进展,概述了不同并行算法的主要内容;探讨了DTA并行技术在海量地形数据可视化和高性能地学计算的应用,随着DEM的需求日益增大,高精度、高分辨率DEM产品及其附加服务也逐步产品化。最后,通过分析并行计算发展的关键问题,提出DTA并行技术的研究趋势及研究意义,合适的数据划分和结果融合策略、通用并行算法、容错机制和负载均衡策略的设计是今后研究的重要内容,尤其是如何在多种计算模式共同发展的背景下利用并行计算解决地学难题,从而得到更接近现实世界地理环境的模拟,并扩大数字地形分析的应用范围。  相似文献   

“07.7”淮河流域梅雨锋暴雨的地形敏感性试验   总被引：2，自引：2，他引：0       下载免费PDF全文

尹宜舟  沈新勇  李焕连 《高原气象》2009,28(5):1085-1094

利用WRFV2.2中尺度数值模式, 对2007年7月8~9日发生在淮河流域的梅雨锋暴雨进行了模拟及相关的地形敏感性试验。结合这次暴雨过程特征, 详细分析了大别山地区地形及皖东南地区地形分别对安徽北部、 湖北北部和河南东南角、 江苏中部降水的影响。结果表明： 在这次降水过程中, 如果没有大别山地区的地形, 安徽北部一带的700 hPa天气系统的发展或移动速度更快, 相关区域降水将加大, 地形在鄂豫地区产生的切变消失, 相应的降水消失, 且地形切变与气流切变叠加时降水更大, 在一定的系统配置条件下, 大别山地区的地形可以影响江苏地区降水的发生\, 发展; 如果没有皖东南地区的地形, 安徽北部系统略有发展, 大别山地区的地形切变作用减弱, 江苏中部的降水大范围减小。  相似文献   

地形动力作用对华北暴雨和云系影响的数值研究   总被引：9，自引：4，他引：5       下载免费PDF全文

廖菲  胡娅敏  洪延超 《高原气象》2009,28(1):115-126

为了进一步研究地形对华北暴雨的影响,本文从云微物理学的角度出发,选取了2005年7月22～24日的一次华北暴雨过程为研究对象,利用中尺度数值模式ARPS,通过地形高度敏感性试验,详细讨论了地形高度变化对流场、云及降水微物理过程的影响.结果表明:地形高度变化对水平和垂直流场的大小和分布都有较大影响;地形高度增加有利于迎风坡附近水平风场辐合和垂直上升运动发展,这对云的垂直和水平发展影响都很大,尤其是对中高层云的发展影响最明显,并且能明显扩大地面降水的分布范围,地面最大降水量也有所增多.这主要是由于地形高度增加后能促进中高层云水的产生,尤其是零度层之上的过冷云水含量的增多,这大大促进了冰相粒子(雪和霰)的增多,从而使得以冷云过程为主的此次降水过程中,冰相粒子融化形成的雨水含量增多.虽然地形高度的增加会抑制云系发展前期的暖云过程,但对冷云过程有持续加强作用,而且不会明显改变云内降水的形成机制,冷云过程依然是降水的最大贡献项,总体上促进了云和降水的发展.  相似文献