共查询到20条相似文献，搜索用时 828 毫秒
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基于C/S模式的气象资料自动下载系统 总被引：1，自引：0，他引：1
我国各级气象台站主要应用PCVSAT单收站系统接收气象卫星广播资料,单收站系统一但发生故障就会影响气象资料的正常接收,导致气象资料缺失。为了确保在单收站设备发生故障时也能及时、完整地接收气象资料,应用计算机编程技术开发了一套气象资料自动下载系统。系统基于现代化的宽带网络传输体系,采用客户机/服务器(C/S)模式构建,当单收站系统发生故障时,应用该系统可以及时、快速、完整地补全缺失的气象资料,没有安装单收站的气象资料用户也可以应用该系统实时接收气象资料。 相似文献
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通过分析CTL-713C多普勒天气雷达数字接收处理系统硬件构成及工作原理,结合硬件状态指示介绍了该型雷达数字接收处理系统的正常工作状态。将CTL-713C多普勒天气雷达数字接收处理系统分成信号处理器、数字接收机、连接三类故障进行诊断,根据终端显示和系统硬件状态指示综合判断相应类型故障的处理方法,通过焦作CTL-713C多普勒天气雷达数字接收处理系统故障实例分析和诊断结果对处理方法进行了验证,并对雷达数字接收处理系统的故障诊断方法和原则进行了总结。 相似文献
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介绍了CINRAD/SB雷达接收系统技术特点。根据接收机的主通道、测试通道、故障定位通道的信号流程,从监测信息、报警信息、关键点参数测量入手,总结了CINRAD/SB雷达接收系统故障诊断方法和技巧。详细介绍了利用RDA计算机的报警信息直接查找故障、通道测试法和关键点波形测试法3种诊断故障的方法,并列举了接收机主通道前端、后端以及测试通道3个不同类型的典型故障个例的分析和处理步骤。提出了接收系统维修方面的一些建议,为新一代天气雷达技术支持和保障提供借鉴。 相似文献
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以风云三号气象卫星国内外多家地面站数据接收故障排查需求为背景,基于Java 1.6,在Eclipse 3.6平台上开发了风云三号气象卫星数据接收远程故障诊断系统,分析了总体框架、构建了故障诊断规则库、阐述了工作流程。该系统可实现对分布式地面站数据接收设备运行状态的远程集中监视、通过解析设备状态报告文件触发自动故障诊断和基于规则的故障诊断,生成故障报告并导入专家经验库,支持文本和图形两种查看方式。经过业务实践检验,该系统界面友好,能够帮助知识工程师远程精准定位故障单元,有效提高了排故效率,增强了集成运行控制中心对各地面站数据接收业务的远程监管能力,对提高风云三号气象卫星及同类卫星数据接收的质量具有一定的实际意义。 相似文献
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我局GMS卫星云图接收系统，安装使用一年多以来，除因电源原因造成一次故障外，运行还比较正常。但人冬以来，特别是出现凌冻结冰后，接收天线结冰使接收质量下降，出现大量掉线和干扰，点，经除冰后，接收质量有所改善，后又出现接收质量下降的问题，发现天线有大量灰尘，清除后接收质量改善。从发生接收质量下降，出现大量掉线和干扰；久的问题看，可能原因有：一是接收机（含高频头）故障。我局因电源原因造成的这次故障，使接收机的调制解调器和高频头故障而出现问题；二是外部干扰造成的问题。随着现代通信技术的发展，传呼台，大哥… 相似文献
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基于分拆数的角色访问控制模型的原理与实现 总被引：2，自引：0，他引：2
介绍了基于分拆数的权限管理策略的原理及其在角色访问控制模型中的应用，实现了一个结构简单、伸缩性好、功能强大的权限管理系统。提出了自然数按集合分拆的新概念，同时给出了一个自然数按某个有限集狭义分拆唯一的充分条件。 相似文献
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Fragments of deep-ocean tidal records up to 3 days long belong to the same functional sub-space, regardless of the record’s origin. The tidal sub-space basis can be derived via Empirical Orthogonal Function (EOF) analysis of a tidal record of a single buoy. Decomposition of a tsunami buoy record in a functional space of tidal EOFs presents an efficient tool for a short-term tidal forecast, as well as for an accurate tidal removal needed for early tsunami detection and quantification [Tolkova, E., 2009. Principal component analysis of tsunami buoy record: tide prediction and removal. Dyn. Atmos. Oceans 46 (1–4), 62–82] EOF analysis of a time series, however, assumes that the time series represents a stationary (in the weak sense) process. In the present work, a modification of one-dimensional EOF formalism not restricted to stationary processes is introduced. With this modification, the EOF-based de-tiding/forecasting technique can be interpreted in terms of a signal passage through a filter bank, which is unique for the sub-space spanned by the EOFs. This interpretation helps to identify a harmonic content of a continuous process whose fragments are decomposed by given EOFs. In particular, seven EOFs and a constant function are proved to decompose 1-day-long tidal fragments at any location. Filtering by projection into a reduced sub-space of the above EOFs is capable of isolating a tsunami wave within a few millimeter accuracy from the first minutes of the tsunami appearance on a tsunami buoy record, and is reliable in the presence of data gaps. EOFs with ∼3-day duration (a reciprocal of either tidal band width) allow short-term (24.75 h in advance) tidal predictions using the inherent structure of a tidal signal. The predictions do not require any a priori knowledge of tidal processes at a particular location, except for recent 49.5 h long recordings at the location. 相似文献
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刘桂馥 《南京气象学院学报》1995,18(4):500-505
不变量方法是一种数字技术，该方法对给定长度有限的时间序列，可以构造出一个常微分方程组。该方程组的解在有限时段上的采样值与给定序列重合。观测研究是对无法确定其方程的动力系统进行的研究；不变量方法提出了动力数值试验的可能性。 相似文献
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采用均一化订正的北京南郊地面日平均气温资料,分析了北京地区1951—2008年气温变化趋势。结果表明,年平均最高和最低气温的升高呈明显的不对称性,其中年平均最低气温升高较为明显,升温趋势为0.46℃/10a。根据1951—2008年日平均气温计算北京春、夏、秋、冬四季的季节长度和起始日期,发现北京地区冬季最长,秋季最短;夏季在逐渐延长,冬季在逐渐缩短,夏、冬两季长度变化的线性速率分别为4.4d/10a和-4.7d/10a。春、夏两季逐渐提前,趋势分别为3.0d/10a和2.5d/10a;而秋、冬两季在逐渐推迟,趋势分别为2.0d/10a和1.7d/10a。将季节起始日期与年平均气温进行相关性分析发现,春、夏两季的起始时间与年平均气温存在显著负相关,而秋、冬两季起始时间与年平均气温存在显著正相关。 相似文献
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Zhaoyang CHAI He ZHANG Mulan ZHANG Xiao TANG Weipeng ZHENG Jiang ZHU Guangqing ZHOU Junji CAO Qingcun ZENG 《大气科学进展》2021,38(10):1611-1620
This article introduces "EarthLab ", a major new Earth system numerical simulation facility developed in China.EarthLab is a numerical simulation system for a physical climate system, an environmental system, an ecological system, a solid earth system, and a space weather system as a whole with a high-performance scientific computing platform.EarthLab consists of five key elements—namely: a global earth numerical simulation system, a regional high-precision simulation system, a supercomputing support and management system, a database, data assimilation and visualization system, and a high-performance computing system for earth sciences. EarthLab helps to study the atmosphere, hydrosphere,cryosphere, lithosphere, and biosphere, as well as their interactions, to improve the accuracy of predictions by integrating simulations and observations, and to provide a scientific foundation for major issues such as national disaster prevention and mitigation. The construction and operation of EarthLab will involve close cooperation with joint contributions and shared benefits. 相似文献
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唐慧强 《南京气象学院学报》1998,21(1):80-84
利用集成硅气压传感器这种具有较大温度系数及非线性误差的典型传感器而设计一智能化的气压仪表,提出了较好地利用分段二次插值的方法,使非线性及温度误差降至完全可被忽略的程度,从而来提高仪表的精度;并提出了利用简易监视计数器等电路的设计来提高可靠性及合理的电路设计来降低功耗提高整机性能等一些完善而实用的方法。 相似文献
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Knowledge on climate change impacts, adaptation, and vulnerability is fragmented, because it is found in disparate case studies which use inconsistent terminology and focus on distinct aspects relevant to adaptation. While large-scale syntheses such as the Assessment Reports of the Intergovernmental Panel on Climate Change provide a high level overview and are useful for international decision-making, there is a need for systematic and flexible access to this research-based knowledge in order to aid future adaptation research and decision-making. Against this background, we present a ‘conceptual’ meta-analysis, a novel approach to meta-analyse studies on climate change impacts, adaptation, and vulnerability in Europe. The meta-analysis results in a classification scheme for relating the diverse studies. This scheme consists of (i) a classification of studies according to the type of adaptation-relevant results they produce and (ii) a hierarchical classification of the regional and thematic context of studies. The implementation of this scheme, for example in the form of a database, overcomes some of the identified gaps of current adaptation knowledge representation. We furthermore present a quantitative analysis of the classified studies that exemplifies how the developed classification scheme can be applied to get a systematic and quantitative overview of the knowledge they contain. Thus, the conceptual meta-analysis and the classification scheme represent a first step towards a systematisation of knowledge on climate change impacts, adaptation, and vulnerability and may be seen as a useful complement to qualitative literature reviews. 相似文献
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A numerical stochastic model is developed for the upcrossing rate across a specified threshold concentration. The model assumes that the concentration time series at a given spatial point within a dispersing plume can be approximated as a first-order Markovian process designed to be consistent with a given time-invariant concentration probability density function (pdf). The model requires only the specification of a concentration pdf with a given mean and variance and a concentration fluctuation integral time scale. Predicted upcrossing rates are compared with atmospheric plume concentration data obtained from a point source near the ground. For this data set, a log-normal pdf is found to give better estimates of the threshold crossing rate than a gamma pdf. 相似文献
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本文对容性支节加载的小型化超表面天线进行了分析与设计.通过在方形贴片上引入一对容性负载支节,可以有效地降低超表面单元的工作频率,从而将传统方形贴片超表面单元的尺寸减小55%.在单元设计的基础上,设计了一款4×4阵列的超表面天线,并采用特征模分析（CMA）解释了超表面天线的辐射机制.为了验证设计思路,对天线进行了加工和测试,测量的-10 dB阻抗带宽为21.7%,并在工作频带内保持6 dBi的辐射增益. 相似文献
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The micromixing technique, widely used in engineering calculations of mixing and chemical reaction, is extended to atmospheric boundary-layer flows. In particular, a model based on the interaction-by-exchange-with-the-conditional-mean (IECM) micromixing approach is formulated to calculate concentration fluctuation statistics for a line source and a point source in inhomogeneous and non-Gaussian turbulence in the convective boundary layer. The mixing time scale is parameterised as a linear function of time with the intercept value determined by the source size at small times. Good agreement with laboratory data for the intensity of concentration fluctuations is obtained with a value of 0.9 for the coefficient of the linear term in the time-scale parameterisation for a line source, and a value of 0.6 for a point source. Calculation of higher-order moments of the concentration field for a line source shows that non-Gaussian effects persist into the vertically well-mixed region. The cumulative distribution function predicted by the model for a point source agrees reasonably well with laboratory data, especially in the far field. In the limit of zero mixing time scale, the model reduces to a meandering plume model, thus enabling the concentration variance to be partitioned into meandering and relative components. The meandering component is shown to be more persistent for a point source than for a line source. 相似文献