共查询到20条相似文献，搜索用时 578 毫秒
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针对目前高分辨率数值模式资料在预报业务中难以有效应用问题,开发了基于Web的数值模式交互显示系统,该系统分为服务器端和浏览器客户端2部分。服务器端由数据接收及处理、Web服务器2个核心模块组成,模式数据处理采用Grib码或NC格式,节省了存储空间并保留了完整的预报信息;利用Python语言Django框架搭建的Web服务器,通过httpRequest机制接收前端绘图信息,在服务器端应用Python扩展包pyGrADS在后台生成预报图形,并以图片的形式返回浏览器,实现了在B/S架构下进行实时交互显示数值模式的功能。在浏览器客户端建立了可自由选择区域和变量的交互前端显示界面,并根据预报思路,设计不同的天气预报图形模板,能够快速生成各种预报图形。 相似文献
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针对保定武装部对气象信息的特定需求，根据需求内容、需求时间、需求环境等，利用PHP和MySQL、Dreamweaver等工具开发了一个基于PHP和MySQL的Web数据库的气象保障系统。运用PHP高级分页技术、访问MySQL数据库技术、图像处理技术等，采用了Web浏览器、Web服务器、数据库服务器3层结构方式研发。根据服务要素的特性划分为不同的功能模块进行制作，实现了各类信息自动更新，动态实时显示天气预报、天气实况、卫星云图等气象信息。实现了数据库资源在Internet的共享访问，搭建了信息交互访问平台，形成了完整、实用的气象保障服务系统。 相似文献
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广西便携式决策气象服务系统 总被引：3，自引：0，他引：3
介绍广西便携式决策服务系统的设计思路和开发过程，指出：融合因特网浏览器技术、以Web网站和超文本网页方式来组织构建决策气象服务系统，是实现决策服务内容表现形式向生动化、形象化和多媒体化转变的重要途径。 相似文献
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介绍如何利用Mono for Android、ASP.NET、C#开发一套可以在智能手机上使用的上行气象信息传输实时监控软件,以保障上行气象信息的时效性。从软件的需求分析、软件架构、软件实现等方面阐述了如何在技术上安全、及时、准确的实现对气象信息传输情况的实时监控,并对主要功能的实现与优化进行了详细介绍：通过Web Service技术获取、发布传输监控信息、进行用户权限控制,优化Web Service性能,以保障监控信息安全、高效的传输;利用后台服务、隐式线程、定时警报实现快速响应、节约系统开销的手机客户端;构建兼容性、独立于分辨率的UI。 相似文献
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黑潮SSTA与赤道太平洋风场及ENSO关系初探 总被引：6，自引：0，他引：6
利用NCEP/NCAR的1950—1998年海表温度场和1958—1997年海表风场再分析资料,采用相关、合成等分析方法,研究了黑潮区域SSTA(sea surface temperature anomaly)与太平洋风场的关系。结果表明:从SSTA滞后风场3月起,与其关系密切的经向风关键区位于赤道西太平洋(140~160°E,5°S~5°N),纬向风关键区位于赤道中太平洋(160°E~150°W,5°S~5°N),两者对SSTA的影响均可持续6月左右;纬向风关键区的强度和范围均大于经向风。进一步研究表明,黑潮SS-TA与ENSO事件有着密切的联系:E l N ino(La N ina)事件当年11月—次年12月期间黑潮海温多为正(负)异常。 相似文献
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北大西洋海表面温度锋与大西洋风暴路径及大气大尺度异常的关系研究 总被引：1，自引：0，他引：1
运用NCEP、Had ISST再分析资料,北大西洋涛动(NAO)月指数序列,探讨了海表面温度(SST)锋的时空变化特征,揭示了北大西洋SST锋的主要气候变率及其与北大西洋风暴轴和大气大尺度环流异常的关系。研究表明,剔除季节循环后的SST锋显示其最主要变率为锋区的向南/北摆动,其对应的风暴轴发生相应的西南/东北移动,并同时在北大西洋上空对应一个跨海盆的位势高度负/正异常。这种环流异常可引起高纬度海平面气压(SLP)的反气旋/气旋式环流,这有利于增强海表面风对大洋副极地环流的负/正涡度异常输入,进一步减弱/加强了高纬度上层冷水向SST锋区的输送。北大西洋SST锋的另一主要模态为锋区在南北方向的分支和合并。当SST锋异常在40°N~45°N以单支形式加强时,对流层位势高度场和SLP南北梯度增大,对应NAO正位相,此时风暴轴也为单支型;同时SLP异常场促使冰岛附近具有气旋式风应力异常,亚速尔地区具有反气旋式风应力异常,导致副极地环流和副热带环流均加强,增加高纬度冷水和低纬度暖水在锋区的输入,从而进一步增强40°N~45°N附近的SST锋区。当SST锋异常在40°N~45°N纬带南北发生分支时,风暴轴也同时出现北强南弱的南北分支,此时对应了负位相NAO,来自北南的冷暖水输送减弱,SST锋也发生减弱分支。此外,位于大洋内区的SST锋东端也存在一个偶极子型的模态,尽管其解释方差相对较小,但仍与偏东北的NAO型具有显著相关。谱分析表明,北大西洋SST锋与风暴轴具有1~3年和年代际共振,与中高纬大尺度环流也存在周期1~3年的共变信号,其中准一年共变信号体现了SST锋和NAO之间的对应关系。进一步诊断分析表明,SST锋上空的近表层大气斜压性和经向温度梯度随着SST锋的增强而增强,经向热通量的向北输送导致涡动有效位能的增加;海洋的非绝热加热产生更强的垂直热量通量,这有利于涡动有效位能释放成为涡动动能,从而表现为该区域的风暴轴加强,并进一步影响风暴轴中的天气尺度扰动与下游大尺度环流异常的相互作用过程。 相似文献
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《大气与海洋》2013,51(3):203-215
Abstract The forecast skill of the Canadian Meteorological Centre (CMC) operational global forecast/analysis system is assessed as a function of scale for the traditional forecast variable of 500‐hPa geopotential height using results from January 2002. These results are compared to an earlier analysis of forecasts from the European Centre for Medium‐range Weather Forecasts (ECMWF) which indicated unexpectedly enhanced skill at high wavenumbers (small scales) especially in the mean forecast component identified with local topographical structures. The global rms error for the CMC forecasts is dominated by the transient component compared to the mean and continues to grow with time during the six days of the forecast. Geographically the transient error grows most rapidly in middle and high latitude regions of large natural variability. The relative error behaves differently and grows most rapidly initially in tropical regions and is inferred to exhibit both climatological and flow‐dependent error growth. In terms of spherical harmonic two‐dimensional wavenumber n, low wavenumber (large scale) 500‐hPa geopotential height structures are dominated by the mean component but beyond wavenumber 10 to 15 the transient component dominates and exhibits an approximately n–5 spectral slope consistent with a quasi‐two dimensional turbulence enstrophy cascading subrange. Error grows slowly for the large scales dominated by mean climatological structures but these are not of interest for daily weather forecasting. Transient error grows rapidly at small scales and penetrates toward larger scales with time in keeping with the expected predictability behaviour. An expression of the form f(n, τ) = 1 – e–τ/τp(n) is fitted to the growth of relative error as a function of wavenumber and forecast range and gives a scale dependent predictability timescale for the transient component that varies as τp ? n?3/2, although the generality of the relationship is not known. The mean component at intermediate/high wavenumbers exhibits an apparent region of enhanced skill in the CMC system apparently connected to the topography. The result supports the possibility that some small‐scale mean flow structures, although containing only a minor amount of variance, are maintained in the face of errors in other scales. The results do not support the level of enhanced skill found in an earlier analysis of ECMWF results suggesting them to be an artefact of the analysis/forecast system in use at the time. 相似文献
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The validity of a common radiometeorological application of Monin-Obukhov (M-O) similarity theory to potential refractivity (), which is a nonlinear combination of and q, is determined by whether the properly nondimensionalized gradient is a universal function of z/L. We develop expressions for the flux of (and its scaling parameter, *) in terms of temperature and moisture fluxes, and an M-O similarity expression for the vertical gradient. Results show that even if and q are accepted as exactly following M-O similarity expressions, when the surface layer is stable, does not obey such an expression. That is, when properly nondimensionalized, the vertical gradient of does not collapse to a single universal function of z/L. The assumption that behaves as a similarity variable is approximately correct for well-mixed surface layers under unstable and near-neutral conditions.The gradient of is an important factor in determining microwave propagation conditions. We demonstrate the error induced in a simple algorithm when is assumed to obey M-O similarity theory. An alternative methodology, consistent with the application of similarity theory to and q, is then developed without requiring that itself satisfy similarity theory. 相似文献
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Max H. Bazerman 《Climatic change》2006,77(1-2):179-193
In this article, I analyze climate change as a “predictable surprise,” an event that leads an organization or nation to react with surprise, despite the fact that the information necessary to anticipate the event and its consequences was available (Bazerman and Watkins, 2004). I then assess the cognitive, organizational, and political reasons why society fails to implement wise strategies to prevent predictable surprises generally and climate change specifically. Finally, I conclude with an outline of a set of response strategies to overcome barriers to change.This paper has benefitted from the excellent input from Alex Todorov, Michael Oppenheimer, and three anonymous reviewers. 相似文献
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Rice paddies as a methane source 总被引：8，自引：0，他引：8
Rice fields are considered to be among the highest sources of atmospheric methane, an important source of global warming. In order to meet the projected rice needs of the increasing world population, it is estimated that the annual world's rough rice production must increase to 760 million tons (a 65% increase) in the next 30 years. This will increase methane emissions from ricefields if current technologies are kept. Methane emissions from ricefields are affected by climate, water regime, soil properties, and various cultural practices like irrigation and drainage, organic amendments, fertilization, and rice cultivars. Irrigated rice comprises 50% of the world-harvested rice area and contributes 70% to total rice production. Because of assured flooding during the growing period it is the primary source of methane. Rainfed rice emits less methane due to periods of droughts. Upland rice, being never flooded for a significant period of time, is not a significant source of methane. There is great potential to develop no regret mitigation options that are in accordance with increasing rice production. 相似文献