Application of synthetic aperture radar (SAR) imagery to volcano mapping in the humid tropics: a case study in East Java, Indonesia   总被引：3，自引：0，他引：3  

Simon A. Carn 《Bulletin of Volcanology》1999,61(1-2):92-105

 Volcanoes in humid tropical environments are frequently cloud covered, typically densely vegetated and rapidly eroded. These factors complicate field and laboratory studies and even the basic identification of potentially active volcanoes. Numerous previous studies have highlighted the potential value of radar remote sensing for volcanology in equatorial regions. Here, cloud- and vegetation-penetrating L_HH-band (λ≈24 cm) synthetic aperture radar (SAR) data from the Japanese Earth Resources Satellite (JERS-1) are used to investigate persistently active volcanoes and prehistoric calderas in East Java, Indonesia. The L_HH-band JERS-1 SAR produces high-spatial-resolution (18 m) imagery with relatively high incidence angle that highlights structures and topographic variations at or greater than the wavelength scale while minimising geometrical distortions such as layover and foreshortening. These images, along with Internet browse data derived from the Canadian RADARSAT mission, provide new evidence relating regional tectonics to volcanism throughout East Java. Volcanic events, such as caldera collapse at the Tengger caldera, appear to have been partly controlled by northwest-aligned faults related to intra-arc sedimentary basins. Similar regional controls appear important at historically active Lamongan volcano, which is encircled by numerous flank maars and cinder cones. A previously undocumented pyroclastic sheet and debris avalanche deposit from the Jambangan caldera complex is also manifested in the synoptic radar images. At the currently active Semeru volcano these data permit identification of recent pyroclastic flow and lahar deposits. Radar data therefore offer a valuable tool for mapping and hazard assessment at late Quaternary volcanoes. The criteria developed in the analysis here could be applied to other regions in the humid tropics. Received: 25 June 1998 / Accepted: 20 January 1999  相似文献   

WSR-88D多普勒天气雷达冰雹探测算法及评价   总被引：10，自引：3，他引：7  

杨引明 《气象》1999,25(5):39-43

详细介绍了ＷＳＲ－８８Ｄ多普勒天气雷达冰雹探测算法的设计,使用,并进一步分析该算法存在的优点和不中,最后,指出业务运行中改进的使用步骤和方法,有效地提高了ＷＳＲ－８８Ｄ多普勒天气雷达探测,预报冰雹的能力。  相似文献   

远旁瓣引起的杂波干扰     

甄广炬 《南京气象学院学报》1999,22(4):734-738

分析了偏角馈入抛物面天线远旁瓣回波产生的机理,并经实验验证了远旁瓣回波的存在。结论显示：偏角馈入抛物面天线较中心馈入抛物面天线在抑制远旁瓣方面有优势,在做低仰角扫描时不会产生远旁瓣回波;但在高仰角时,也会产生远旁瓣回波。在多卜勒雷达的使用中,控制天线的转速有利于消除远旁瓣回波的影响。  相似文献   

用单多卜勒雷达确定中尺度气旋环流中心及最大风速半径     

马翠平  张培昌 《南京气象学院学报》1999,22(3):403-407

首先给出具有 Ｒａｎｋｉｎｅ 模式的中尺度气旋的模拟多卜勒径向速度图,然后利用多卜勒雷达观测的径向速度与实际气流间的几何关系,提出一种确定近似轴对称的中尺度气旋中心及最大风速半径的方法。  相似文献   

机载雷达定量测雨中雨滴谱参数的优化   总被引：2，自引：0，他引：2  

窦贤康 Amaye.  P 《应用气象学报》1999,10(3):293-298

机载雷达可以方便地跟踪观测对象,并且可以观测某些地基雷达较难观测的区域（如海洋）,因此近年来在大气遥感领域得到越来越广泛的应用。为了获得一个较好的地面分辨率,机载雷达使用X波段的衰减频率。虽然雷达波受到的衰减通过算法可以进行订正,但由于雨滴谱的范围较宽,使得利用Z-R或k-R经验公式来确定雨强仍具有较大的不确定性。该文应用在西太平洋进行的国际大型科学考察实验TOGA/COARE中1993年1月和2月间取得的机载雷达实测数据进行定量测雨中雨滴谱参数优化的尝试。  相似文献   

机载雷达定量测雨中衰减效应的订正研究   总被引：2，自引：0，他引：2  

窦贤康  刘万栓  刘锦丽 《大气科学》1999,23(4):403-410

星载测雨雷达的应用,必须满足一些主要条件:高的空间分辨率、宽阔的覆盖范围、大的动态降雨测量范围以及精确的点测量等。由于技术条件的限制,满足这些条件的雷达工作在被雨衰减的频率段,因此必须修正由于衰减所导致的误差。对于单波束单频雷达,kZS（衰减系数-雷达反射因子-海表反射率）算法在一个较大的雨强范围内对衰减效应的订正效果较好。本文将kZS应用到在西太平洋进行的国际大型科学考察实验TOGA/COARE中1993年1月和2月间取得机载雷达（和星载雷达频率相近）实测数据,进行雨空间分布的研究,取得了和模拟研究预期相吻合的结果。  相似文献   

三维构造模拟方法--体平衡技术研究   总被引：9，自引：0，他引：9  

毛小平  吴冲龙  袁艳斌 《地球科学》1999,24(5):506-508

为了实现三维构造史模拟,在二维平衡剖面技术的基础上,提出了适用于在维构造模拟的方法－体平衡技术,其核心是通过分析断层演化及地层变形在三维空间中的特殊性,建立三维复杂构造的数学模型和三维物质平衡方法,它简化了平衡时三维的体积计算和对不平衡体积构造体的适应性,从而减少了三维构造模拟的实现难度。  相似文献   

地下深部灰岩岩石特性的单孔雷达反射研究   总被引：4，自引：0，他引：4  

黄家会  宋雷 《水文地质工程地质》1999,26(6):57-59

灰岩中岩溶和裂隙发育规律研究是研究陷落柱发育规律的基础,研究结果表明在单孔雷达反射图像上岩溶和裂隙反映清晰,单孔雷达反射法用于灰岩岩石特性研究效果显著,该研究成果填补了国内灰岩岩石特性的单孔雷达反射研究的空白,为地下深处灰岩岩石特性高分辨率探测开辟了新途径。  相似文献   

Preliminary study on weathering and pedogenesis of carbonate rock   总被引：23，自引：0，他引：23  

Shijie Wang  Hongbing Ji  Ziyuan Ouyang  Dequan Zhou  Leping Zhen  Tingyu Li 《中国科学D辑(英文版)》1999,42(6):572-581

South China is the largest continuous distribution area of carbonate rock in the world. The origin of the soils over the bedrock carbonate rock has long been a controversial topic. Here further exploration is made by taking five soil profiles as examples, which are developed over the bedrock dolomitite and limestone and morphologically located in upland in karst terrain in the central, west and north Guizhou as well as west Hunan, and proved to be the weathering profiles of carbonate rock by the research results of acid-dissolved extraction experiment of bedrock, mineralogy and trace element geochemistry. Field, mineralogical and trace element geochemical characteristics of weathering and pedogenesis for carbonate rock are discussed in detail. It is pointed out that weathering and pedogenesis of carbonate rock are important pedogenetic mechanisms for soil resources in karst area, providing a basis for further researches on the origin of soils widely overlying bedrock carbonate rocks in South China. Project supported by the National Natural Science Foundation of China (Grant No. 498330003) and National Key Basic Research Project (Grant No. 95pre-39).  相似文献   

高频地波雷达单站测量表层海流的原理     

杜勇 《中国海洋大学学报(自然科学版)》1999,(2)

运用高频地波雷达测量表层海流矢量,一般均采用双站测量方案,因而,需要大量的人力和昂贵的设备投入。该项研究在分析双站测量原理的基础上,结合海洋学原理和合理的假设,推导并给出了利用单站地波雷达测量表层海流的原理和公式,从而使单站测量表层海流成为可能。可预期该方案虽然在一定程度上,适当降低了空间分辨率,但却可以大幅度降低观测成本,减少人力物力的投入,并显著提高现场观测效率。  相似文献