从太湖流域旱涝史料看历史气候信息处理   总被引：15，自引：1，他引：14  

陈家其 《地理学报》1987,(3)

历史气候信息处理建立在信息提取的基础上,目的在于建立一套方法,将定性的历史气候信息转化为气候变化参数,并消除各种不均—性,从而建立历史气候序列。本文着重介绍建立太湖流域历史旱涝等级序列的方法与步骤: 1)确立信息源,建立信息网络;2)站点等级的确定与订正;3)弱信息处理;4)信息的综合。  相似文献   

基于MODIS数据的浒苔信息提取方法研究   总被引：6，自引：0，他引：6  

刘振宇  江涛 《测绘科学》2008,(Z1)

浒苔是一种大型绿藻,大量浒苔爆发会严重影响景观,干扰旅游观光和水上运动的进行。本文利用NASA提供的MODIS02的250m分辨率影像,分别采用了比值法、归一化植被指数法和监督分类中的最小距离分类,提取了浒苔的信息,实验结果表明,三者都可以提取浒苔信息,但是比值法提取的结果最好,最小距离分类很难与薄云区分,必须加入人工目视解译,归一化植被指数可以区分出薄云,但是遗漏较多。  相似文献   

石太线下行K135滑坡特征与成因分析     

曹金亮  魏放  韩颖 《中国地质灾害与防治学报》2005,16(1):49-52

滑坡位于石太线下行K135路段右侧偏西，平面上呈近似椭圆形，由原有老滑坡复活而形成。根据滑坡勘察，滑坡所处地貌单元属侵蚀剥蚀低中山区，滑坡区地层组成为第四系松散堆积物下伏晚古生代二叠系石千峰组泥岩、砂岩互层。在分析滑坡几何特征、地质构造特征、水文地质条件及滑坡变形破坏特征的基础上，探讨了滑坡的成因，认为老滑坡的成因以自然形成为主，新滑坡则发育并活动于老滑坡堆积物中，因某部门在老滑坡体前缘修建收费站，进行了大面积不适当的工程开挖，形成临空面，加之降雨的作用降低了土体的粘聚力及抗剪强度，在上覆岩土体的重力作用下形成新滑坡。老滑坡为巨型厚层滑坡，属于自然滑坡，新滑坡为大型中层滑坡，属于工程滑坡。  相似文献   

用远场辐射场反演云闪放电参数   总被引：2，自引：0，他引：2  

祝宝友  陶善昌  马明  吕伟涛 《气象学报》2004,62(4):498-503

用地面电磁场遥感闪电放电参数无论是在实际应用还是理论研究中都具有重要意义。文中基于电流传输线模式 ,提出了一种用单站远场VLF/LF辐射场反演云内放电参数的简便方法。当传输线电流从底部传播到顶部的时间只有几微秒时 ,整个传输线的VLF/LF辐射可以近似成偶极子辐射 ,即远场辐射场与电流的时间变化率和传输线长度的乘积成正比。因此 ,对远场辐射场做时间积分就能获得完整的电流矩波形 (上升沿有所加宽 ) ,而且传输线模式中的重要参数 ,电流从底部传播到顶端经历的时间 ,也可以近似地用辐射场时间积分幅度与辐射场幅度之比来估计。这一方法具有估计云闪双极性大脉冲辐射过程的放电参数的潜力。  相似文献   

Formation and shortening deformation of a back-arc rift basin revealed by deep seismic profiling, central Japan   总被引：1，自引：0，他引：1  

Hiroshi Sato  Takaya Iwasaki  Shinji Kawasaki  Yasutaka Ikeda  Nobuhisa Matsuta  Tetsuya Takeda  Naoshi Hirata  Taku Kawanaka   《Tectonophysics》2004,388(1-4):47

The northern Fossa Magna (NFM) basin is a Miocene rift system produced in the final stages of the opening of the Sea of Japan. It divides the major structure of Japan into two regions, with north-trending geological structures to the NE of the basin and EW trending structures to the west of the basin. The Itoigawa-Shizuoka Tectonic Line (ISTL) bounds the western part of the northern Fossa Magna and forms an active fault system that displays one of the largest slip rates (4–9 mm/year) in the Japanese islands. Deep seismic reflection and refraction/wide-angle reflection profiling were undertaken in 2002 across the northern part of ISTL in order to delineate structures in the crust, and the deep geometry of the active fault systems. The seismic images are interpreted based on the pattern of reflectors, the surface geology and velocities derived from refraction analysis. The 68-km-long seismic section suggests that the Miocene NFM basin was formed by an east dipping normal fault with a shallow flat segment to 6 km depth and a deeper ramp penetrating to 15 km depth. This low-angle normal fault originated as a comparatively shallow brittle/ductile detachment in a high thermal regime present in the Miocene. The NFM basin was filled by a thick (>6 km) accumulation of sediments. Shortening since the late Neogene is accommodated along NS to NE–SE trending thrust faults that previously accommodated extension and produce fault-related folds on their hanging wall. Based on our balanced geologic cross-section, the total amount of Miocene extension is ca. 42 km and the total amount of late Neogene to Quaternary shortening is ca. 23 km.  相似文献   

Les laves du mont Bangou : une première manifestation volcanique éocène, à affinité transitionnelle,de la Ligne du Cameroun     

Jacob Fosso  Jean-Jacques Ménard  Jacques-Marie Bardintzeff  Pierre Wandji  Félix M. Tchoua  Hervé Bellon 《Comptes Rendus Geoscience》2005,337(3):315-325

Mount Bangou, an Eocene volcano (⁴⁰K–⁴⁰Ar ages between 44.7 and 43.1 ± 1 Ma) is the oldest dated volcano of the Cameroon Line. In this region, two magmatic series, evolving by fractional crystallization, show transitional affinities that are exceptionally known in this sector. Mineral compositions of basaltic rocks (scarce modal olivine and occurrence of normative hypersthene) as well as geochemical characteristics (low Ba, La, Ta contents and high Y/Nb ratios) are in agreement with this trend. The succession of magmas evolving in time from transitional to more typical alkaline compositions is evidenced in a continental setting. To cite this article: J. Fosso et al., C. R. Geoscience 337 (2005).  相似文献   

Weakness and mechanical anisotropy of phyllosilicate-rich cataclasites developed after mylonites of a low-angle normal fault (Simplon Line,Western Alps)     

《Journal of Structural Geology》2016

The Simplon Fault Zone is a late-collisional low-angle normal fault (LANF) of the Western Alps. The hanging wall shows evidence of brittle deformation only, while the footwall is characterized by a c. 1 km-thick shear zone (the Simplon Fault Zone), which continuously evolved, during exhumation and cooling, from amphibolite facies conditions to brittle-cataclastic deformations. Due to progressive localization of the active section of the shear zone, the thermal-rheological evolution of the footwall resulted in a layered structure, with higher temperature mylonites preserved at the periphery of the shear zone, and cataclasites occurring at the core (indicated as the Simplon Line). In order to investigate the weakness of the Simplon Line, we studied the evolution of brittle/cataclastic fault rocks, from nucleation to the most mature ones. Cataclasites are superposed on greenschist facies mylonites, and their nucleation can be studied at the periphery of the brittle fault zone. This is characterized by fractures, micro-faults and foliated ultracataclasite seams that develop along the mylonitic SCC′ fabric, exploiting the weak phases mainly represented by muscovite and chlorite. Approaching the fault core, both the thickness and frequency of cataclasite horizons increase, and, as their thickness increases, they become less and less foliated. The fault core itself is represented by a thicker non-foliated cataclasite horizon. No Andersonian faults or fractures can be found in the footwall damage zone and core zone, whilst they are present in the hanging wall and in the footwall further from the fault. Applying a stress model based on slip tendency, we have been able to calculate that the friction coefficient of the Simplon Line cataclasites was <0.25, hence this fault zone is absolutely weak. In contrast with other fault zones, the weakening effect of fluids was of secondary importance, since they accessed the fault zone only after an interconnected fracture network developed exploiting the cataclasite network.  相似文献   

研究气温变化趋势的新方法——三组耐抗线     

刘俊卿  杨军  强德厚 《干旱气象》2007,25(1):79-82

针对气象资料难以满足高斯分布的情况,引进了具有耐抗性的三组耐抗线方法,分析了满足不同信度情况下最小二乘回归和三组耐抗线的差异,并用西藏近30 a气温资料进行了检验。结果表明三组耐抗线方法比最小二乘法研究气候变化趋势有明显优势;采用最小二乘法得到的西藏气候变暖估计偏高。  相似文献   

Gentrification as space domestication. The High Line Art case     

Pier Luigi Sacco  Maria Tartari  Guido Ferilli  Giorgio Tavano Blessi 《Urban geography》2019,40(4):529-554

In this paper, we critically examine the role of artistic locational choices and practices in the context of gentrification processes in urban renewal contexts. We characterize gentrification as a form of domestication of space, and explore the extent to which artistic choices and practices relate to such process with reference to the deontological dilemma of legitimization within the art system vs. responsible empowerment of vulnerable local constituencies. We illustrate our argument with an analysis of the High Line Art project, and show how this can be considered as a textbook example of art-driven space domestication leading to brutal forms of gentrification. We comment on the threat that this provides to the social credibility of artistic practices as an agency of responsible social change.  相似文献   

Analyzing Population Density Disparity in China with GIS-automated Regionalization: The Hu Line Revisited     

WANG Fahui  LIU Cuiling  XU Yaping 《中国地理科学(英文版)》2019,(4):541-552

The famous ’Hu Line’, proposed by Hu Huanyong in 1935, divided China into two regions(southeast and northwest) of comparable area size but drastically different in population. However, the classic Hu Line was derived manually in absence of reliable census data and computational technologies of modern days. It has been subject to criticism of lack of scientific rigor and accuracy. This research uses a GIS-automated regionalization method, termed REDCAP(Regionalization with Dynamically Constrained Agglomerative Clustering and Partitioning), to reconstruct the demarcation line based on the 2010 county-level census data in China. The results show that the logarithmic transformation of population density is a better measure of attributive homogeneity in derived regions than density itself, and produces two regions of nearly identical area size and greater contrast in population. Specifically, the revised Hu Line by Hu Huanyong in 1990 had the southeast region with 94.4% of total population and 42.9% of total land, and our delineation line yields a southeast region with 97.4% population and 50.8% land. Therefore, the population density ratio of the two regions is 27.1 by our line, much higher than the ratio of 22.4 by the Hu Line, and thus outperforms the Hu Line in deriving regions of maximum density contrast with comparable area size. Furthermore, more regions are delineated to further advance our understanding of population distribution disparity in China.  相似文献