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兰州台阵勘址测点的功率谱估计与分析 总被引：5，自引：9，他引：5
引言 兰州台阵是根据全面禁止核试验条约（CTBT）而建立的国际监测系统（IMS）中规定的基本台站之一（郑重，2000）。1999年8月2日至25日，在经过了图上作业、宏观勘察、初选台点计算和观测设计之后，IMS地震处与中国地震局地球物理研究所对兰州台阵阵址进行了勘址观测。在勘址观测中，双方以同心圆分布和直线分布方式在兰州大尖山台阵阵址进行了为期18天的野外观测。本文主要以中方仪器记录的数据对各测点的背景噪声功率谱进行了计算和分析，并对各测点白天和晚上的平均功率谱作了比较。 1 观测仪器与观测数据 1.1 观测仪器 中方在兰… 相似文献
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兰州台阵勘址测点对相干函数的计算与分析 总被引：4，自引：3，他引：4
引言兰州台阵是根据全面禁止核试验条约（CTBT）而建立的国际监测系统（IMS）中规定的基本台阵之一（郑重,徐智强,2000）。1999年8月2日至25日,中国地震局投入了FBS-3A宽频带地震仪、JCV-100型短周期地震仪,以同心圆和直线分布方式（图1）在兰州大尖山台阵阵址进行了为期18天的野外观测,记录了约3GB的波形数据。 相似文献
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海拉尔兰州核查地震台阵的勘址和地动噪声功率谱的计算 总被引：9，自引：7，他引：2
根据《全面禁止核试验条约》,在海拉尔和兰州现有三分向地震台的基础上建设两个地震台阵。为此目的,中国地震局地球物理研究所（ＩＣ／ＣＳＢ）与全面禁止核试验条约组织国际监测系统（ＣＴＢＴＯ／ＩＭＳ）对两个新台阵进行了勘址观测。实地勘址开始于１９９９年初。１９９９年８月和９月分别在兰州和海拉尔进行了勘址观测。兰州台阵阵址们于甘肃省兰州市西南１８ｋｍ处;海拉尔台阵阵址们于内蒙古自治区海拉尔市东北３４ｋｍ处。勘址观测仪器由ＩＭＳ提供的６套宽频带地震计及２４位数据采集器组成。仪器在两个阵址分别布设于２０个左右的侯选点进行观测,从兰州阵址较浅的摆坑到海拉尔阵址摆坑深至地表以下８ｍ。地球物理研究所与ＩＭＳ联合对数据进行了分析。结果显示两个地区大多数观测点的地噪声功率谱在高于１Ｈｚ的频域上均低于宽频带台站的平均值。 相似文献
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兰州台阵勘址测点均方根值的计算与分析 总被引：1，自引：2，他引：1
引言 中国是全面禁止核试验条约(CTBT)缔约国之一,根据全面禁止核试验条约组织(CTBTO)建设国际监测系统(IMS)的计划,经我国有关部门批准,中国地震局地球物理研究所将建设兰州台阵。1999年8月,地球物理研究所台阵建设技术实施组经过实地考察,从几个候选阵址中选中兰州地震台西南方向18 km处的大尖山作为兰州台阵阵址。台阵阵址位于兰州南部的雾宿山区,有着稳定的基岩,在附近没有发现大的活断层。 台阵建设需要有噪声场稳定的场地,为了确定台阵阵址各勘址测点的噪声源与噪声的普遍变化,在中国地震局分析预报中心的支持下,共投入了一套FB… 相似文献
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自60年代初期将地震台阵的方法和技术用于检测微弱地震及侦查地下核试验的地震信号以来,利用地震台阵技术和方法所开展的地震学研究及地下核试验侦查等方面的工作都取得了较大的进展。多年来,台阵观测实践和结果也说明了地震学方法是侦查地下核试验的主要方法,地震台阵则是地震观测的主要手段之一。 相似文献
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在哈萨克斯坦的5个现代化数字地震台阵中,4个小孔径同心圆结构的IMS简约型台阵建设、维护方便,全方位监测能力强,1个十字型结构中等孔径台阵,因对特定方位敏感,对更远距离已知核试验点监测能力更强。台阵观测场地均处于完整稳定的构造块体,内部岩石迁移性良好,噪声水平低,保证了对远处微弱地震信号的监测及各子台信号的相似性。地震检波器良好的性能,保证了台阵的地震信号记录质量和数据研究基础。采用卫星传输方式,有效保证了数据的实时性。哈萨克斯坦的地震台阵,其选址、布局、仪器、数据传输等台阵建设,为中国地震台阵发展建设提供了经验借鉴。 相似文献
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随着我国社会经济的发展,地震台站观测环境破坏日益严重。对兰州地震台阵环境噪声进行调研,定量分析并提供该台阵与国际标注各大干扰源的直线距离,以充分了解各干扰源对地震台阵的影响程度。结果发现,兰州地震台阵目前基本达到Ⅰ级台站环境噪声水平,满足台阵观测条件。 相似文献
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介绍了上海地震台阵观测系统，该观测系统是由地震台阵、佘山数据中心、上海信息中心等部分组成，对各部分的功能及设备系统结构作了较为翔实的分析，并简要描述了台阵数据处理软件系统。上海地震台阵投入并网运行后表明，从根本上改善了地震波形、特别是远震波形的记录，并从总体下提出了上海地震台网的地震综合监测能力。 相似文献
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Gtz Schroth Luciana Ferreira Da Silva Marc‐Andree Wolf Wenceslau Geraldes Teixeira Wolfgang Zech 《水文研究》1999,13(10):1423-1436
The partitioning of rain water into throughfall, stemflow and interception loss when passing through plant canopies depends on properties of the respective plant species, such as leaf area and branch angles. In heterogeneous vegetation, such as tropical forest or polycultural systems, the presence of different plant species may consequently result in a mosaic of situations with respect to quantity and quality of water inputs into the soil. As these processes influence not only the water availability for the plants, but also water infiltration and nutrient leaching, the understanding of plant effects on the repartitioning of rain water may help in the optimization of land use systems and management practices. We measured throughfall and stemflow in a perennial polyculture (multi‐strata agroforestry), monocultures of peach palm (Bactris gasipaes) for fruit and for palmito, a monoculture of cupuaçu (Theobroma grandiflorum), spontaneous fallow and primary forest during one year in central Amazonia, Brazil. The effect on rain water partitioning was measured separately for four useful tree species in the polyculture and for two tree species in the primary forest. Throughfall at two stem distances, and stemflow, differed significantly between tree species, resulting in pronounced spatial patterns of water input into the soil in the polyculture system. For two tree species, peach palm for fruit (Bactris gasipaes) and Brazil nut trees (Bertholletia excelsa), the water input into the soil near the stem was significantly higher than the open‐area rainfall. This could lead to increased nutrient leaching when fertilizer is applied close to the stem of these trees. In the primary forest, such spatial patterns could also be detected, with significantly higher water input near a palm (Oenocarpus bacaba) than near a dicotyledonous tree species (Eschweilera sp.). Interception losses were 6·4% in the polyculture, 13·9 and 12·3% in the peach palm monocultures for fruit and for palmito, respectively, 0·5% in the cupuaçu monoculture and 3·1% in the fallow. With more than 20% of the open‐area rainfall, the highest stemflow contributions to the water input into the soil were measured in the palm monocultures and in the fallow. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
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M. N. French R. L. Bras W. F. Krajewski 《Stochastic Environmental Research and Risk Assessment (SERRA)》1992,6(1):27-45
A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities. 相似文献
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M. A. Kahn 《洁净——土壤、空气、水》2000,28(2):95-101
Red tide, a recurrent phenomenon has become conspicuous in several Kashmir lake ecosystems since 1991. The responsible organism (Euglena pedunculata), a rare flagellate rediscovered in the Kashmir Himalaya (Khan 1993) caused first and unprecedented red tide outbreak, constituting a maximum of 96% of resident numerical phytoplankton density in Dal Lake. At present, conflicting hypotheses exist on the generation of causal assemblage(s) imparting redness to waters: Jeeji Bai (1991) linked its origin to acid precipitation – a fallout of burning oil‐fields during the Gulf War – whilst Khan (1993) holds local factor(s) responsible. Field/experimental studies support the latter contention that the influx of untreated sewage, in unison with warm temperatures, high levels of PhAR, iron and interruption to hydrological flow‐pattern together with absence/or reduction in grazing activity created conducive environmental milieu for red tide outbreak. Dal Lake “red tide” drifted the bloom‐inoculum to other waters, including Lake Wular, where additional ecological niches were carved out, threatening the aesthetic value and biological diversity of Kashmir lakes. Ecological monitoring indicates frequent seasonal red tide occurrence in Dal Lake (including summer‐autumn event of 1998) which testifies its unabated eutrophication status. Further studies are needed on ecological adaptability and biogeographic distribution of this rare and unique red tide‐causing flagellate. 相似文献