远程教育系统中卫星小站的防雷电设计

分析了雷电引入卫星小站系统的途径,阐述了卫星小站系统的防雷电措施,提出了构筑完整防雷体系保护系统设备的方法。     

9210工程单收站系统

９２１０工程在全国地市以上气象局建立了收发双向ＶＳＡＴ卫星小站 ,实现了气象信息的高速传输。为满足县以下气象台站及非气象部门对气象信息的需求 ,中国气象局推出了“９２１０工程单收站系统”。该系统采用中国广播卫星公司研制的ＰＣＶＳＡＴ高速卫星信息广播系统。１ＰＣＶＳＡＴ高速卫星信息广播系统概述基于ＰＣＶＳＡＴ的高速卫星信息广播系统是一个典型的单向卫星通信系统。由一个主站和众多的接收小站组成。主站将各种信息汇接处理成高速数据码流 ,经调制、上变频、放大后 ,由大型天线向卫星发送。单收站接收卫星转发的信号 ,解…     

9210工程的防雷设计

ＶＳＡＴ小站的防雷包括外部防护和内部防护。外部防护包括建筑物和ＶＳＡＴ天线,内部防护包括各种金属管线、电源线和信号线。提出了防护的技术指标和具体措施,可基于避免ＶＡＳＴ小站发生雷击。     

卫星通信小型地球站雷电防护技术

卫星通信小型地球站(VSAT小站)这一现代通信系统正越来越多地在国内外得到广泛应用。由于VSAT小站的部件主要由大规模集成电路构成并且设备安装时常常将天线置于楼顶,因此,在日常工作中因遭受雷电袭击而造成设备损坏的事件常常发生。本文主要依据《建筑物防雷设计规范》、《微波站防雷与接地设计规范》和IEC有关标准,结合目前国内气象、海关、烟草、金融等行业大量使用的VSAT通信小站结构原理和现代雷电防护理论,就如何对其进行雷击电磁脉冲的综合防护进行了探讨。强调了在现代防雷接地系统中,重要的是等电位系统的结构而不是接地电阻阻值的大小。     

地市级CMACast卫星接收小站的设备管理与故障处理

介绍了中国气象局卫星数据通信系统CMACast地市级接收小站运行维护的步骤和方法,并针对容易出现的故障进行了诊断分析,并结合实例对常用故障处理方法予以说明。     

卫星通信入门（四）

第四章VSAT及其组网我国正在建设的气象卫星综合业务应用系统（9210工程），将采用VSAT卫星通信系统在北京设立卫星VSAT主站（又称枢纽站、控制中心、HUB），在区域中心和省设置卫星VSAT次站（有监测功能地面小站），在地市和部分天气雷达站设置VSAT小站，组成具有数据广播、数据交换和一定话音能力的气象专用卫星通信网。l什么是VSAT？VSAT（VerySmallApertureTerminal）是指甚小口径天线的智能卫星地球站。VSAT卫星通信网通常由大量此类甚小口径终端地球站与一个大型枢纽站协同工作，支持广域的双向综合电信和信息业务。V…     

县级CMACast系统安装及注意事项

<正>中国气象局卫星数据广播系统(以下简称CMACast系统)具有每天广播400GB数据资料的能力,系统的建成进一步提高广播气象资料的种类、数量、时效性和可靠性。该系统硬件安装分为卫星接收天线和接收机的安装、县级小站计算机安装;软件接收系统采用SuSE Linux操作系统,安装时需注意该目录共享和产品调用问题。     

气象卫星综合业务系统

介绍了中国气象局“９２１０工程”的建设目的、内容及我省ＶＳＡＴ卫星通信系统的设计情况，论述了卫星数据小站、话音小站、混合小站安装调试的方法和步骤，并介绍了我省 计算机网络系统设备和系统软件的配置情况。     

浅谈PCVSAT卫星单向接收小站的环境建设

就现代通信及计算机应用系统而言,可靠的硬件装备、先进的软件配置、优良的运行环境是支撑系统稳定运行的三大支柱。PCVSAT卫星单向接收小站的建设是我省9210工程建设的延伸,省局将按统一计划、统一组织的原则实施。由于各地硬件设备及软件系统的规范性、统一性,其配置和功能一般都能够较好地体现中国气象局关于系统的设计思路,实现系统的设计目标。而环境建设则不然,PCVSAT卫星单收小站的建设涉及我省79个县级台站,各单位的场地设施、电源供电、雷电防护、地网埋设条件不尽相同,甚至差异较大,加之实际施工中测试手段的相对欠…     

全球导航卫星系统基准站防雷设计

针对全球导航卫星系统(GNSS)基准站容易遭受雷击损失严重的问题,从GNSS基准站自身特点出发,参考传统建筑物防雷设计方法,依据防雷设计原则,分析了GNSS基准站的防雷等级,从外部防雷和内部防雷两方面对防雷过程中接闪、引下线、接地、等电位连接、屏蔽、合理布线等重要环节及电涌保护器等重要装置进行了研究,设计出各环节的具体防雷措施。实际应用表明所设计的方法科学实用、安全可靠,能够有效地提高基准站的防雷效果。     

加强业务管理提高测报质量

我局从1999～2003年,测报工作连续4年未出现错情,在此期间共有1个250个班,9个百班无错通过上级业务部门验收.在仪器保管、使用、维护上符合要求,对外报送的各种表、簿都能做好出门合格.     

On the forecast of the onset and end of the convective season in the Amazon

Summary ?Some features of the climate system that can be considered predictors of the onset and end of the convective season over the Amazon were identified using one-month lag correlations and field composites. The fields analyzed were sea surface temperature (SST), outgoing long-wave radiation (OLR), vertical velocity and upper tropospheric winds. Warm (cold) anomalies in the SST in the tropical North Atlantic and the Caribbean Sea tend to be associated with delayed (early) onsets. Likewise, there is a tendency towards a delayed (early) end of the convective season with cold (warm) anomalies in these ocean regions. In addition, the SST in the cold tongue region of the equatorial Pacific is negatively, though weakly correlated with the onset date. The signal of this SST is more evident in the case of the end date, which is earlier with respect to its mean date in most of El Ni?o cases. The convective activity intensity itself conditions the onset and the end of the convective season, as it is evidenced by the behavior of the OLR and the vertical velocity fields. The more (less) intense the convective activity over South America during the preceding month, the earlier the onset and the later the end of the convective season on the Amazon region. The prediction of the onset and end dates of the convective season in the Amazon region was explored using a simple multiple regression technique based on the variables that have shown precursor signals with respect to these dates. The correlation coefficient between the predicted and the observed onset date is 0.81, and in the case of the end date, it is 0.76. The skill to predict early, delayed and normal categories was high, since in more than two thirds of the cases the category was successfully predicted, and there were no predictions of categories opposed to those observed. Received July 23, 2001; revised February 22, 2002; accepted April 26, 2002     

准两年振荡对大气中微量气体分布的影响

NCAR的包含化学、辐射、动力相互作用的两维模式（SOCRATES）移植回国后进行了初步的模拟试验,用以研究某些对环境问题重要的微量气体的化学、辐射、动力传输过程。在不考虑极地平流层云和气溶胶表面非均相化学等情况下,模式积分多年,计算结果稳定,模拟的风场、温度场显示出正常的季节变化,模拟的微量气体分布与卫星实测资料对照,结果也比较一致。为了探讨热带平流层风场的准两年周期振荡（QBO）对平流层微量气体分布的影响,我们做了QBO强迫的数值试验,即在模式中加入QBO强迫,并与不考虑QBO强迫的模拟结果对比。结果表明,QBO与其相关的次级环流所引起动力输送的变化,使平流层微量气体分布发生变化。     

Comparing the theoretical versions of the Beaufort scale, the T-Scale and the Fujita scale

2005 is the bicentenary of the Beaufort Scale and its wind-speed codes: the marine version in 1805 and the land version later. In the 1920s when anemometers had come into general use, the Beaufort Scale was quantified by a formula based on experiment. In the early 1970s two tornado wind-speed scales were proposed: (1) an International T-Scale based on the Beaufort Scale; and (2) Fujita's damage scale developed for North America. The International Beaufort Scale and the T-Scale share a common root in having an integral theoretical relationship with an established scientific basis, whereas Fujita's Scale introduces criteria that make its intensities non-integral with Beaufort. Forces on the T-Scale, where T stands for Tornado force, span the range 0 to 10 which is highly useful world wide. The shorter range of Fujita's Scale (0 to 5) is acceptable for American use but less convenient elsewhere. To illustrate the simplicity of the decimal T-Scale, mean hurricane wind speed of Beaufort 12 is T2 on the T-Scale but F1.121 on the F-Scale; while a tornado wind speed of T9 (= B26) becomes F4.761. However, the three wind scales can be uni-fied by either making F-Scale numbers exactly half the magnitude of T-Scale numbers [i.e. F′half = T / 2 = (B / 4) − 4] or by doubling the numbers of this revised version to give integral equivalence with the T-Scale. The result is a decimal formula F′double = T = (B / 2) − 4 named the TF-Scale where TF stands for Tornado Force. This harmonious 10-digit scale has all the criteria needed for world-wide practical effectiveness.     

Quantifying the uncertainty of the annular mode time scale and the role of the stratosphere

The impact of high resolution modern vegetation cover on the West African climate is examined using the International Centre for Theoretical Physics Regional Climate Model implementing the NCAR Community Land Model. Two high resolution 25 km long-term simulations driven by the output from a coarser 50-km resolution simulation are performed for the period 1998–2010. One high resolution simulation uses an earlier and coarser-resolution version of plant functional type distribution and leaf area index, while the other uses a more recent, higher-quality, and finer-resolution version of the data. The results indicate that the new land cover distribution substantially alters the distribution of temperature with warming in Central Nigeria, northern Gulf of Guinea and part of the Sahel due to the replacement of C4 grass with corn; and cooling along the coastlines of the Gulf of Guinea and in Central Africa due to the replacement of C4 grass with tropical broadleaf evergreen trees. Changes in latent heat flux appear to be largely responsible for these temperature changes with a net decrease (increase) in regions of warming (cooling). The improved land cover distribution also results in a wetter monsoon season. The presence of corn tends to favor larger precipitation amounts via more intense events, while the presence of tropical broadleaf evergreen trees tends to favor the occurrence of both more intense and more frequent events. The wetter conditions appear to be sustained via (1) an enhanced soil moisture feedback; and (2) elevated moisture transport due to increased low-level convergence in regions south of 10N where the most substantial land cover differences are present. Overall the changes induced by the improved vegetation cover improve, to some extent, the performance of the high resolution regional climate model in simulating the main West African summer monsoon features.     

Analysis of the Characteristics of the Low-level Jets in the Middle Reaches of the Yangtze River during the Mei-yu Season

Here, we analyze the characteristics and the formation mechanisms of low-level jets(LLJs) in the middle reaches of the Yangtze River during the 2010 mei-yu season using Wuhan station radiosonde data and the fifth generation of the European Centre for Medium-Range Weather Forecasts(ERA5) reanalysis dataset. Our results show that the vertical structure of LLJs is characterized by a predominance of boundary layer jets(BLJs) concentrated at heights of 900–1200 m.The BLJs occur most frequently at 230...     

由中国历史气候记录对季风导致唐朝灭亡说的质疑

2007年1月4日杂志发表了Yancheva等10人的题为"Influence of the intertropical convergence zone on the East-Asian monsoon"(热带辐合带对东亚季风的影响)的论文[1],这是德国波兹坦地学研究中心气候动力与沉积学科的主管豪格(G.H.Haug)率领的科研小组的一项成果,认为是季风的变化引起的长期干旱导致了唐朝的灭亡.     

流场配置及地形对西南低涡形成的动力作用

本文采用定常二层模式讨论较小地形及高、低层流场配置对西南低涡形成的动力作用。指出了西南低涡的形成是与盆地、河谷以及其上气流分层有关的一种定常态.在上、下为西风分层时期,低层的浅薄暖湿西风有利于西南低涡的形成.在上、下为东、西风分层时期,上层浅薄东风亦有利于西南低涡的形成.小型的凸起山脉对西南低涡的形成没有作用.