分组交换网发报中遇到的问题及处理

目前，各地地面测报业务中引入的X．２８分组交换网发报线路，将原来公用电话、甚高频传递报文方式，改为计算机网络传输，提高了报文的传输效率和准确性。但由于从拨号到完成传报的自动处理过程是“黑箱”操作，当出现问题时，测报人员常不知所措。本人在实践中对X．２８分组交换网线路发报有了进一步了解，现将使用X．２８分组交换网中线路发报工作遇到的问题及解决方法，介绍给同行。１X．２８分组交换网的线路发报工作原理X．２８分组交换网线路发报工作，实际包括两个部分：（１）通过win９５或win９８下的“拨号网络”呼叫连接在本…     

X.25分组交换网主要设备的简明配置

介绍了X．25分组交换网建设过程中主要设备的具体配置及关键设备参数的具体设置。     

河源市气象局防灾减灾网络服务系统

本系统充分利用河源市气象局现有的气象资料和信息,紧密依托9210工程、分组数据交换网和日常应用的基本业务系统,建立了内部的NT文件服务器。结合分组数据交换网系统的文件服务功能,将分组数据交换网获取的气象信息产品资源共享,同时将9210工程获取的气象信息产品,     

利用WindowsNT Server实现X.25路由的方法

以Ｗｉｎｄｏｗｓ 95/ 98和ＷｉｎｄｏｗｓＮＴ为主的计算机操作系统已成为当今微机操作系统的主流 ,这类操作系统具有能提供网络互联的功能。然而 ,在湖北省大多数地 (市、州 )级气象台站公用分组交换网节点机上所使用的仍是ＤＯＳ操作系统 ,这给多进程通信带来极大不便。如果利用ＷｉｎｄｏｗｓＮＴＳｅｒｖｅｒ来担当分组交换网节点机并充当网络的路由器 ,再通过Ｘ .2 5将省一级气象台网络和各地 (市、州 )级气象台的内部网络互联 ,那么存在于气象通信中的有关上下行资料传输自动化问题就会得到相应的解决。该文以十堰市气象局利用ＮＴ备…     

分组交换网与市—县气象业务实时系统

通过对沈阳市市－县气象业务实时系统的介绍，给出了公用分组交换网应用于气象业务的实例，由于分组交换网是当代数据通信的得要手段之一，故该系统所采用的方法可推广到其他类似的系统中。     

用分组交换网实现通信的原理分析

１前言 为了使气象电报能实时可靠地传输到有效地点,我们进行了分组交换网络工程的建设,分组交换是利用公用数据网（Ｘ．２５）,采用报文交换的”存储一转发”机制,把报文分成较短的、规格化了的”分组”进行交换和传输的方式。它有很多优点适合我们气象部门使用,例如：可靠性高、经济性好、传输时延较小等。２分组交换的原理２．１数据交换方式 交换方式是指计算机之间、计算机与终端之间或各终端之间为交换信息所用信息格式和交换装置的方式。目前有下列三种交换方式：２．１．１电路交换 这种交换方式通过呼叫,在交换双方之间直接…     

X.25分组数据交换网在县站的综合应用

随着气象通信建设的逐步完善 ,随着 92 1 0气象卫星通信工程的业务化运行 ,广东省气象通信体制一改原来的人工支线电话、电报传送而形成以卫星信道为主 ,地面Ｘ 2 5公共分组数据交换网为辅的新通信体制。针对韶关地区Ｘ 2 5网、92 1 0通信系统在县气象站的综合应用情况 ,希望对全省县级气象台站管理人员提供一定的帮助和借鉴。图 1　韶关市县级Ｘ 2 5网络框架示意图1　Ｘ 2 5网的应用情况概述　　Ｘ 2 5网目前在我省气象部门主要用于气象观测资料上行传输和 92 1 0卫星接收的辅助 ,在韶关市县级气象台站已经实现了这一方式。Ｘ 2 5网是基于…     

盟市气象局与所属旗县气象局拨号网络及分组交换网的连接方法

随着“9210”工程的业务化运行及办公自动化、NOTES系统的应用，各旗县气象局分组交换网线路全面开通。由于旗县局分组交换网通信业务的联结方式是利用分组网信道，通过六合公司开发的专用通信传输软件进行业务信息传输，并未加载TCP／IP协议，因此造成业务环节增多，通信不畅，     

梅州市气象台资料传送与处理系统

目前,广东省市一级气象台气象资料和信息的获取有三种途径:ＰＥＳ接收、单收站接收和通过Ｘ25分组交换网从区域气象中心获取。从运行情况来看,这三种途径各有优缺点:从单收站获取数据速度最快,但缺报率最高;ＰＥＳ的接收率比较有保证,但有时会因硬盘容量问题造成一段时间?..     

市—县气象信息自动化传输系统

为适应办公自动化传输的需要，以X．25分组交换网为依托，在Windows95／98环境下，用VB，DEL-PHI语言设计了业务应用软件，包括信息编辑、信息浏览、信息传输等功能。     

IMPACT OF ATMOSPHERIC LOW-FREQUENCY OSCILLATION ON THE IMMIGRATION OF NILAPARVATA LUGENS(STL) IN HUNAN AND JIANGXI PROVINCES

Various features of the atmospheric environment affect the number of migratory insects, besides their initial population. However, little is known about the impact of atmospheric low-frequency oscillation(10 to 90 days) on insect migration. A case study was conducted to ascertain the influence of low-frequency atmospheric oscillation on the immigration of brown planthopper, Nilaparvata lugens(Stl), in Hunan and Jiangxi provinces. The results showed the following:(1) The number of immigrating N. lugens from April to June of 2007 through 2016 mainly exhibited a periodic oscillation of 10 to 20 days.(2) The 10-20 d low-frequency number of immigrating N. lugens was significantly correlated with a low-frequency wind field and a geopotential height field at 850 h Pa.(3) During the peak phase of immigration, southwest or south winds served as a driving force and carried N. lugens populations northward, and when in the back of the trough and the front of the ridge, the downward airflow created a favorable condition for N. lugens to land in the study area. In conclusion, the northward migration of N. lugens was influenced by a low-frequency atmospheric circulation based on the analysis of dynamics. This study was the first research connecting atmospheric low-frequency oscillation to insect migration.     

ANALYSIS OF “BIMODAL PATTERN” STORM ACTIVITY CHARACTERISTICS OF THE BAY OF BENGAL

Storms that occur at the Bay of Bengal (BoB) are of a bimodal pattern, which is different from that of the other sea areas. By using the NCEP, SST and JTWC data, the causes of the bimodal pattern storm activity of the BoB are diagnosed and analyzed in this paper. The result shows that the seasonal variation of general atmosphere circulation in East Asia has a regulating and controlling impact on the BoB storm activity, and the “bimodal period” of the storm activity corresponds exactly to the seasonal conversion period of atmospheric circulation. The minor wind speed of shear spring and autumn contributed to the storm, which was a crucial factor for the generation and occurrence of the “bimodal pattern” storm activity in the BoB. The analysis on sea surface temperature (SST) shows that the SSTs of all the year around in the BoB area meet the conditions required for the generation of tropical cyclones (TCs). However, the SSTs in the central area of the bay are higher than that of the surrounding areas in spring and autumn, which facilitates the occurrence of a “two-peak” storm activity pattern. The genesis potential index (GPI) quantifies and reflects the environmental conditions for the generation of the BoB storms. For GPI, the intense low-level vortex disturbance in the troposphere and high-humidity atmosphere are the sufficient conditions for storms, while large maximum wind velocity of the ground vortex radius and small vertical wind shear are the necessary conditions of storms.     

LOW-FREQUENCY CIRCULATION AND EXTENDED-RANGE FORECAST IN CONNECTION WITH AUTUMN EXTREME HEAVY RAINFALL PROCESS IN HAINAN

Observed daily precipitation data from the National Meteorological Observatory in Hainan province and daily data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis-2 dataset from 1981 to 2014 are used to analyze the relationship between Hainan extreme heavy rainfall processes in autumn (referred to as EHRPs) and 10–30 d low-frequency circulation. Based on the key low-frequency signals and the NCEP Climate Forecast System Version 2 (CFSv2) model forecasting products, a dynamical-statistical method is established for the extended-range forecast of EHRPs. The results suggest that EHRPs have a close relationship with the 10–30 d low-frequency oscillation of 850 hPa zonal wind over Hainan Island and to its north, and that they basically occur during the trough phase of the low-frequency oscillation of zonal wind. The latitudinal propagation of the low-frequency wave train in the middle-high latitudes and the meridional propagation of the low-frequency wave train along the coast of East Asia contribute to the ‘north high (cold), south low (warm)’ pattern near Hainan Island, which results in the zonal wind over Hainan Island and to its north reaching its trough, consequently leading to EHRPs. Considering the link between low-frequency circulation and EHRPs, a low-frequency wave train index (LWTI) is defined and adopted to forecast EHRPs by using NCEP CFSv2 forecasting products. EHRPs are predicted to occur during peak phases of LWTI with value larger than 1 for three or more consecutive forecast days. Hindcast experiments for EHRPs in 2015–2016 indicate that EHRPs can be predicted 8–24 d in advance, with an average period of validity of 16.7 d.     

宁波地区海-陆下垫面差异对雷暴过程影响的数值模拟

利用耦合Noah陆面过程的WRF模式对2009年6月5日傍晚发生在宁波地区的一次雷暴过程进行数值模拟,通过改变下垫面覆盖类型的敏感性试验,探讨了海洋和陆地下垫面对雷暴过程的影响。结果表明,WRF模式能够较合理地模拟出雷暴的发生、发展过程。雷暴发生前期,由于海-陆强烈的热力差异,海风特征明显,海风引起的抬升运动触发了雷暴,海风形成的强辐合区对应雷暴过程累积降水量的大值区。当研究区域全部被替换成陆地后,地表的粗糙度增大,在研究区域东部由于摩擦辐合加强,产生了强烈的上升运动,多个发展旺盛的对流单体在上升运动区生成,使雷暴产生的降水区域东扩、降水量增大、雷暴维持时间延长。当研究区域所有陆地被替换成水体后,白天地表通量减小,大气边界层中湍流运动减弱,边界层高度降低,大气层结变得稳定,不利于对流发展。     

COMPARATIVE ANALYSIS OF VARIOUS DATA OF AIR–SEA TEMPERATURE DIFFERENCE AND ITS VARIATION ACROSS SOUTH CHINA SEA IN THE PAST 35 YEARS

Using the International Comprehensive Ocean-Atmosphere Data Set(ICOADS) and ERA-Interim data, spatial distributions of air-sea temperature difference(ASTD) in the South China Sea(SCS) for the past 35 years are compared,and variations of spatial and temporal distributions of ASTD in this region are addressed using empirical orthogonal function decomposition and wavelet analysis methods. The results indicate that both ICOADS and ERA-Interim data can reflect actual distribution characteristics of ASTD in the SCS, but values of ASTD from the ERA-Interim data are smaller than those of the ICOADS data in the same region. In addition, the ASTD characteristics from the ERA-Interim data are not obvious inshore. A seesaw-type, north-south distribution of ASTD is dominant in the SCS; i.e., a positive peak in the south is associated with a negative peak in the north in November, and a negative peak in the south is accompanied by a positive peak in the north during April and May. Interannual ASTD variations in summer or autumn are decreasing. There is a seesaw-type distribution of ASTD between Beibu Bay and most of the SCS in summer, and the center of large values is in the Nansha Islands area in autumn. The ASTD in the SCS has a strong quasi-3a oscillation period in all seasons, and a quasi-11 a period in winter and spring. The ASTD is positively correlated with the Nio3.4 index in summer and autumn but negatively correlated in spring and winter.     

淮河流域水文极值预测模型研究

为探索气候变化影响下水文极值的非平稳性和预测方法,建立了水文极值非平稳广义极值（GEV）分布的统计预测模型。利用1952-2010年淮河上游流域累计面雨量和流量年最大值资料、同期500 hPa环流特征量资料以及17个CMIP5模式对环流特征量的模拟结果,筛选出对水文极值影响显著的年平均北半球极涡强度指数作为GEV分布参数的预测因子。分析了在RCP2.6、RCP4.5和RCP8.5情景下2006-2050年淮河上游流域水文极值对气候变化的响应。结果表明,10年以下与10年以上重现期的水文极值在非平稳过程中呈现前者下降而后者上升的相反变化趋势;多模型预测的集合平均在未来情景中均呈现上升趋势,情景排放量越大增幅越大,重现期越长增幅也越大。与极值的常态相比,极值的极端态更易受气候变化影响。     

AN ATTRIBUTION ANALYSIS OF CHANGES IN POTENTIAL EVAPOTRANSPIRATION IN THE BEIJING–TIANJIN–HEBEI REGION UNDER CLIMATE CHANGE

Based on the measurements obtained at 64 national meteorological stations in the Beijing–Tianjin–Hebei (BTH) region between 1970 and 2013, the potential evapotranspiration (ET0) in this region was estimated using the Penman–Monteith equation and its sensitivity to maximum temperature (Tmax), minimum temperature (Tmin), wind speed (Vw), net radiation (Rn) and water vapor pressure (Pwv) was analyzed, respectively. The results are shown as follows. (1) The climatic elements in the BTH region underwent significant changes in the study period. Vw and Rn decreased significantly, whereas Tmin, Tmax and Pwv increased considerably. (2) In the BTH region, ET0 also exhibited a significant decreasing trend, and the sensitivity of ET0 to the climatic elements exhibited seasonal characteristics. Of all the climatic elements, ET0 was most sensitive to Pwv in the fall and winter and Rn in the spring and summer. On the annual scale, ET0 was most sensitive to Pwv, followed by Rn, Vw, Tmax and Tmin. In addition, the sensitivity coefficient of ET0 with respect to Pwv had a negative value for all the areas, indicating that increases in Pwv can prevent ET0 from increasing. (3) The sensitivity of ET0 to Tmin and Tmax was significantly lower than its sensitivity to other climatic elements. However, increases in temperature can lead to changes in Pwv and Rn. The temperature should be considered the key intrinsic climatic element that has caused the "evaporation paradox" phenomenon in the BTH region.     

Data selection using support vector regression

Geophysical data sets are growing at an ever-increasing rate, requiring computationally efficient data selection(thinning)methods to preserve essential information. Satellites, such as Wind Sat, provide large data sets for assessing the accuracy and computational efficiency of data selection techniques. A new data thinning technique, based on support vector regression(SVR), is developed and tested. To manage large on-line satellite data streams, observations from Wind Sat are formed into subsets by Voronoi tessellation and then each is thinned by SVR(TSVR). Three experiments are performed. The first confirms the viability of TSVR for a relatively small sample, comparing it to several commonly used data thinning methods(random selection, averaging and Barnes filtering), producing a 10% thinning rate(90% data reduction), low mean absolute errors(MAE) and large correlations with the original data. A second experiment, using a larger dataset, shows TSVR retrievals with MAE < 1 m s-1and correlations 0.98. TSVR was an order of magnitude faster than the commonly used thinning methods. A third experiment applies a two-stage pipeline to TSVR, to accommodate online data. The pipeline subsets reconstruct the wind field with the same accuracy as the second experiment, is an order of magnitude faster than the nonpipeline TSVR. Therefore, pipeline TSVR is two orders of magnitude faster than commonly used thinning methods that ingest the entire data set. This study demonstrates that TSVR pipeline thinning is an accurate and computationally efficient alternative to commonly used data selection techniques.     

Light-absorbing particles in snow and ice: Measurement and modeling of climatic and hydrological impact

Light absorbing particles(LAP, e.g., black carbon, brown carbon, and dust) influence water and energy budgets of the atmosphere and snowpack in multiple ways. In addition to their effects associated with atmospheric heating by absorption of solar radiation and interactions with clouds, LAP in snow on land and ice can reduce the surface reflectance(a.k.a., surface darkening), which is likely to accelerate the snow aging process and further reduces snow albedo and increases the speed of snowpack melt. LAP in snow and ice(LAPSI) has been identified as one of major forcings affecting climate change, e.g.in the fourth and fifth assessment reports of IPCC. However, the uncertainty level in quantifying this effect remains very high. In this review paper, we document various technical methods of measuring LAPSI and review the progress made in measuring the LAPSI in Arctic, Tibetan Plateau and other mid-latitude regions. We also report the progress in modeling the mass concentrations, albedo reduction, radiative forcing, and climatic and hydrological impact of LAPSI at global and regional scales. Finally we identify some research needs for reducing the uncertainties in the impact of LAPSI on global and regional climate and the hydrological cycle.     

前寒武纪气候演化中的三个重要科学问题

自地球形成至寒武纪将近40亿年（距今46亿～5.4亿年,通常称为前寒武纪）的气候演变是一个具有特殊难度和挑战性的研究领域,同时也是基础和前沿的研究领域。文章选择了前寒武纪气候演化中的三个重要科学问题进行综述：大气演化、两次全球性的冰川期以及暗弱太阳问题。关于大气演化,本文首先描述了大气成分的演化历史,然后简述了影响大气成分演化的三个基本过程：大气逃逸、两次大气氧含量突然增加、碳酸盐-硅酸盐循环及其对气候系统的负反馈作用。两次全球性的冰川期分别发生在古元古代（距今24亿～21亿年）和新元古代（距今8亿～5.8亿年）,文章简述了其成因以及相关的气候模拟结果。暗弱太阳问题是地球历史气候演化的一个经典问题,论文简要地综述了一些最新的研究成果和观点。