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环境感知应用系统广泛应用在工业生产、日常生活等领域.本文主要研究环境感知应用系统中的数据收集、安全传输和安全管理等技术,提出了环境感知应用系统架构图,包括环境数据采集单元、数据传输网络及云数据中心,从数据的收集、传输、存储、应用、管理等多个方面保护环境数据的安全性.首先,本文阐述了数据在环境感知应用系统中的收集和传输流程,然后,分析数据从环境数据源传输到现场控制单元,再接入互联网传输到云数据中心采用的安全传输方式.最后,研究了可应用于云数据中心的多种安全防护方法以保护数据安全,包括敏感数据加密、数据隔离、访问控制、权限管理、审计日志、备份恢复等. 相似文献
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京津冀地区冬半年污染传输特征及传输指数的改进 总被引：3，自引：1，他引：2
文章通过轨迹聚类、潜在源区分析等方法对京津冀地区冬半年污染物传输特征进行了分析,在此基础上对传输指数的构建方法进行了改进,并结合一次重污染天气过程分析了其作用。结果表明,对于北京、天津和石家庄,其重污染轨迹出现概率从高到低均为偏南路径、偏西路径、偏东路径和西北路径;在近地面高度上,西南和东南风的增强在大多时候成为北京的污染物传输通道,其中东南方向的污染物来源主要集中在大气低层;改进后的传输指数能够更好地反映外来传输作用对本地污染物浓度的影响,京津冀及周边地区的传输作用对北京、天津和石家庄等大城市的污染物浓度影响较明显,其中城郊及周边地区的近距离传输影响最为显著;合理应用传输指数可以对重污染天气的成因进行初步判断。 相似文献
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我国城市气象服务的若干进展和未来发展 总被引：9，自引：1，他引：9
该文简要介绍了我国城市中尺度气象监测和特种观测、数值预报模式引进和产品释用研究及城市环境气象研究、预报等方面的研究进展，并提出了城市气象服务发展中应解决的城市气象服务定位、工程和产业、数据库、数值模式应用研究和电子信息技术应用等问题。 相似文献
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贵州省气象通信业务监控及自动转报系统 总被引：2，自引：0，他引：2
“贵州气象通信业务监控及自动转报系统”的研究,实现了将贵州省各个发报站点传至贵州省气象局网络服务器的各个时次及各类报文进行分类,以多媒体方式实施实时监控,对监测到的各类报文进行检误、订正,并将省规定的文件名命名方式按传输至指定区域的命名方式进行重新命名处理,使参加全球、全国、各个区域中心及全省交换的各类报文符合相应的规定标准,并按要求将规范化后的各类报文文件自动传输至指定的区域。从而最大限度的减轻报务员的工作量,并大幅度提高报文传输的准确率和及时性。 相似文献
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新一代中尺度自动气象站网络监测系统 总被引：1，自引：3，他引：1
介绍了新一代监测系统的通讯方式、系统构成和软件实现.该系统采用CAWS系列自动气象站作为研究对象,通讯方式采用以无线为主有线为辅的新型通讯传输,利用3层C/S结构和B/S结构相结合的方式实现功能设计;通过基于SQL Server 2000关系型数据库的二次开发,新一代中尺度自动气象站网络监测系统利用自动气象站采集的数据资料进行了各种气象观测方法以及数据应用的研究,是综合地面观测、分析、预测预警、网络发布等功能为一体的新一代监测系统. 相似文献
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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… 相似文献
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Current Lagrangian particle dispersion models, used to simulate the dispersion of passive tracers in the turbulent planetary boundary layer (PBL), assume that the density is constant within the PBL. In deep PBLs, where the density at the boundary-layer top may be lower by more than 20% than at the surface, this assumption leads to errors in the tracer concentrations on the order of 10%. In the presence of a vertical wind shear, this also leads to inaccurate calculations of the horizontal tracer transport. To remove this deficiency, a Langevin equation is presented that contains a density correction term. The effect of the density correction is studied using data from a large-scale tracer experiment. It is found that for this experiment, the main effect of the density correction is an increase in the surface tracer concentrations, whereas the horizontal tracer transport patterns remain largely unaffected. 相似文献
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Tropospheric transport of continental tracers towards Antarctica under varying climatic conditions 总被引：1，自引：0，他引：1
We present a method to analyse tracer transit time climatologies based on the concept of tracer age. The method consists of introducing idealized, short-lived radioactively decaying tracers in a general circulation model of the atmosphere. Tracer age since emission is calculated at any given place in the atmosphere from the ratio of the concentrations of tracers with different lifetimes emitted over the same source area. An obvious use of this method is the analysis of transport of real tracers with similar lifetimes (such as dust particles) during different climatic periods. Here, this method is applied to transport from southern hemisphere continental source areas towards Antarctica at the present, the last glacial maximum (21 kyr BP) and the last glacial inception (115 kyr BP). It is found that the variation over time of atmospheric transport efficiency towards Antarctica depends on the tracer source region: changes for Patagonian tracers differ from those for tracers originating over Australia and southern Africa. Transport towards Antarctica during the last glacial maximum (LGM) is faster for Patagonian, but not for Australian and Southern African tracers. It is shown that for the time of the last glacial inception, tracer transit time towards Antarctica is not significantly different from the present, although signs of a more vigorous atmospheric circulation can be seen in the simulation. 相似文献
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The radon transport test, which is a widely used test case for atmospheric transport models, is carried out to evaluate the tracer advection schemes in the Grid-Point Atmospheric Model of IAP-LASG （GAMIL）. Two of the three available schemes in the model are found to be associated with significant biases in the polar regions and in the upper part of the atmosphere, which implies potentially large errors in the simulation of ozone-like tracers. Theoretical analyses show that inconsistency exists between the advection schemes and the discrete continuity equation in the dynamical core of GAMIL and consequently leads to spurious sources and sinks in the tracer transport equation. The impact of this type of inconsistency is demonstrated by idealized tests and identified as the cause of the aforementioned biases. Other potential effects of this inconsistency are also discussed. Results of this study provide some hints for choosing suitable advection schemes in the GAMIL model. At least for the polax-region-concentrated atmospheric components and the closely correlated chemical species, the Flux-Form Semi-Lagrangian advection scheme produces more reasonable simulations of the large-scale transport processes without significantly increasing the computational expense. 相似文献
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边界层对流对示踪物抬升和传输影响的大涡模拟研究 总被引：3，自引：1，他引：2
利用"西北干旱区陆气相互作用野外观测实验"加密观测期间敦煌站的实测资料以及大涡模式, 通过一系列改变地表热通量和风切变的敏感性数值试验, 分析了地表热通量和风切变对边界层对流的强度、形式, 以及对对流边界层结构和发展的影响。模拟结果显示风切变一定, 增大地表热通量时, 由于近地层湍流运动增强, 向上输送的热量也较多, 使对流边界层变暖增厚, 而且边界层对流的强度明显增强, 对流泡发展的高度也较高。当地表热通量一定, 增大风切变时, 由于风切变使夹卷作用增强, 将逆温层中的暖空气向下卷入混合层中, 使对流边界层增暖增厚, 但是对流泡容易破碎, 对流的强度也较弱。另外通过在模式近地层释放绝对浓度为100的被动示踪物方法, 用最小二乘法定量地分析了地表热通量和风切变分别与示踪物抬升效率和传输高度的关系。分析结果表明, 风切变小于10.5×10-3 s-1时, 增大地表热通量加强了上层动量的下传, 使示踪物的抬升效率也线性增大;地表热通量小于462.5 W m-2时, 增大风切变减弱了边界层对流的强度, 从而使示踪物的抬升效率减弱。当风切变一定时, 示踪物的平均传输高度随地表热通量增加而增大, 而地表热通量一定, 只有风切变大于临界值时, 示踪物平均传输高度才随风切变的增加而增大, 而临界风速的大小由地表热通量决定。 相似文献
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N. Chaumerliac R. Rosset M. Renard E. C. Nickerson 《Journal of Atmospheric Chemistry》1992,14(1-4):43-51
Gases emitted in the planetary boundary layer can be transported very efficiently to the free troposphere through vertical motion along a frontal surface. A mesoscale numerical model was used to simulate the vertical transport of a tracer by clouds during frontogenesis in a moist atmosphere (an evolving Eady wave) in order to illustrate such vertical transport conditions. It is shown that the efficient vertical transport of a tracer occurs only when clouds are present, either when a surface or an in-situ source is considered. Insoluble, partially soluble, and soluble tracers are studied in order to determine the relative importance of vertical transport and scavenging on their redistribution. 相似文献
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Numerical simulations of tracer transport in an idealised, east-west aligned valley are performed with the Regional Atmospheric
Modeling System (RAMS), both two-dimensional and three-dimensional. The results are qualitatively consistent with wintertime
observations in the Austrian Inn Valley. The simulations show an asymmetry in wind circulation and tracer distribution between
the valley sidewalls according to the orientation of the slope with respect to the sun. Two-dimensional sensitivity experiments
are run to investigate the influence of vertical inhomogeneities in thermal stratification and vegetation coverage on the
slope-wind circulation and therewith the tracer transport. It is shown that a transition to a layer of higher stability or
to a region with higher surface albedo causes a reduction of the mass flux in the upslope-wind layer and due to mass continuity
a quasi-horizontal transport out of the slope-wind layer. 相似文献
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R. Salerno 《Theoretical and Applied Climatology》1992,45(1):19-35
Summary Dispersion and transport over complex terrain have been recognized as an important research field. In July 1988, for studying atmospheric dispersion in a mountain area, a tracer experiment has been performed in south alpine valleys near a mountain (Campo dei Fiori, 1226 m.a.s.l.). In this area air masses circulation in wind breeze conditions is frequent. This paper analyses the meteorological situation and the tracer dispersion during those experiments. First a reconstruction of the three-dimensional wind fields overCampo dei Fiori area, taking into account the effects of orography, surface thermal gradients, atmospheric stability and energy of air masses, has been performed. Then the tracer concentrations have been evaluated by means of suitable models and the results have been discussed.With 11 Figures 相似文献
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Latitudinal distribution of radon-222 flux from continents 总被引：1，自引：0，他引：1
Global atmospheric transport models are frequently tested by using 222 Rn as a tracer. Generally this tracer is assumed to be emitted at a uniform rate (1 atom cm−2 s−1 ) from all ice-free land surfaces. The analysis of published data suggests a strong decrease from 30°N northwards to 0.2 atom cm−2 s−1 at 70°N. This could be a result of increasing water tables and proportions of organic soils as indicated by larger proportions of wetlands in northern latitudes. 相似文献
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Tracer transport in the atmosphere is controlled not only by synoptic-scale to mesoscale weather disturbances but also by microscale boundary-layer processes especially under fair-weather conditions. The present study investigates numerically the diurnal variation of boundary-layer convection and cumulus clouds and their role in transporting tracers by conducting high-resolution simulations that explicitly resolve turbulent eddies. The transport of dust aerosols in a desert area under two distinct stability conditions is specifically examined. Convection plays a significant role in transporting dust upward; in other words, the vertical depth of the dust transport is critically determined by the depth of convection. Deep convection is effective in transporting dust into the free atmosphere. The early morning stratification strongly regulates the temporal evolution and the vertical growth of convection and therefore the amount of tracer emission and transport. A sensitivity to model resolution of O (1 km) in a cloud-resolving simulation range is also examined. A proper parameterization for activating microscale convection is required for representing the diurnal variation of convection and tracer transport. 相似文献
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R. M. Banta L. D. Olivier W. D. Neff D. H. Levinson D. Ruffieux 《Theoretical and Applied Climatology》1995,52(1-2):27-42
Summary The study investigates two effects that a valley or canyon opening onto a plain can have on flow and contaminant dispersion over the downwind plain. The first effect is the channeling of strong ambient flow by the canyon when the wind is nearly aligned with the canyon axis. Two cases showed that these conditions produced a region of focused flow downwind of the canyon mouth. The second effect is the formation of canyon exit jets on nights with weaker ambient flow. In two case studies under these conditions strong exit jets formed that were several hundred meters deep. The jets remained narrow and strong at least 10 km onto the plains, and in one of the cases the jet extended more than 20 km over the plains. These deep jets only lasted 2–3 h, and they had a small but significant effect on surface-released tracer transport as indicated by surface sampling. We hypothesize that the near-surface advection of tracer was accomplished by a thin katabatic layer of flow, and that an elevated release or elevated sampling would have indicated a greater effect of the exit jet on tracer transport.With 18 Figures 相似文献