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Simulation of a Summer Urban Breeze Over Paris 总被引:4,自引:0,他引:4
Numerical simulations for an anticyclonic summer episode in the Paris area have been performed at the meso- scale for a 48-hour period, and compared to observations from a dense operational observational network. The meteorological stations have been classified, according to the extent of urbanization of their surroundings, into four classes (central Paris, urban, suburban, and rural). The atmospheric model, coupled with an urban surface scheme, correctly reproduces the temperature (within 1 K from the observations) and humidity. The intense urban heat island during the night is also well represented.Following the validation, the model is used to quantify atmospheric effects of Paris on the boundary layer, through a comparison with a purely rural simulation. At night, the model simulates a neutral or even slightly unstable boundary layer to a depth of 200 m over the city. In contrast, a very stable layer formed in the countryside. During the day, the boundary layer was more turbulent and 500 m deeper over Paris; vertical velocities of up to 1 m s-1 were created over the city. This leads to an urban breeze with convergence at low levels (with winds around 5 to 7 m s-1), and divergence at the boundary-layer top (with similar wind speeds). The horizontal extent of the breeze reaches for more than 50 km from the city centre, and could have an important impact on pollutant diffusion in the area for calm days.Finally, three other spring cases are presented briefly. These show that an urban breeze develops if the synoptic wind is weak enough or disorganized; an urban plume develops otherwise. 相似文献
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天气预报质量评估监控系统的研究与开发 总被引:1,自引:0,他引:1
针对人工方法评定天气预报质量的弊端,荆门市气象科技人员从天气预报业务实际出发,研制并开发出一套天气预报质量评估与监控系统。简单介绍了该系统的开发环境和设计思路,着重阐述了系统的主要功能。最后指出了系统的五大设计特点。 相似文献
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利用南海季风试验研究(1997~2000)的成果资料,对强弱南海夏季风年广西的天气作了对比研究,主要分析了雨季开始、年雨量分配及丰欠、热带气旋活动特点等方面的差异并归纳出一个简单的预测概念模型,可供业务工作者在制作年景预测上参考。 相似文献
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山葡萄的品质决定着葡萄酒的质量,葡萄浆果糖度决定着葡萄品质。葡萄成熟过程中浆果含糖量和含酸量是相互制约的,含糖量主要呈对数略显“S”型变化,含酸量呈指数曲线型变化。将成熟期葡萄浆果含糖量作为葡萄品质的评价指标,利用通化产区19952016年成熟期山葡萄浆果含糖量的实测数据与气象条件进行相关分析,得出山葡萄品质与5月9月上旬积温、7月8月日照时数、5月9月上旬水热系数、8月9月上旬积温关系密切,相关关系均通过了α为0.05或0.01的显著性检验。利用多元回归统计方法建立了山葡萄品质气象预测预报模型,模型的判定系数R^2为0.815,通过了α=0.01的显著性检验。模型的拟合检验平均误差百分率为3.91%。利用2017年、2018年资料对模型进行试报检验,误差百分率分别为1.59%和3.79%。模型具有较高的准确率,能够满足通化产区山葡萄栽培对气象预报和服务的需求。 相似文献
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将原始数据转换为分析型数据,增强用户对海量数据的分析能力,是数据仓库技术最核心、最有价值的思想,也是数据仓库在气象领域应用的基础。该文针对天气预报领域数据空间性、瞬变性、物理性和多尺度性等特点,提出了五元组描述的天气预报分析型数据概念模型;总结了生成分析型数据的固定区域统计、划分区域统计、基本天气系统识别和天气学概念模型识别4种聚集变换,并对其关键技术进行了讨论。提出了基本天气系统自动识别的滤波-划分-测量算法,探讨了针对气象数据特点的模糊空间关系,定义了进行天气学概念模型识别的空间模糊产生式规则,并针对空间数据给出了定位条件等扩展。 相似文献
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河南省暴雪天气特征及预报模型 总被引:5,自引:0,他引:5
普查了1951~1998年冬季河南省降雪资料,确定了河南省区域性暴雪过程,建立了河南省区域性暴雪过程历史资料库,分析了60年代以来我省暴雪的时空分布特征及其天气形势特征,建立了预报模型,并提出了预报着眼点。 相似文献
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MM5模式是国际上应用比较广泛的一种中尺度气象模式,因为它采用了非静力平衡动力框架、可选择的多种物理过程以及四维同化(FDDA)等先进技术,在气象科研和业务预报领域取得了广泛的应用。由于技术的原因,MM5模式一直运行在UNIX系统之下,直接在Windows系统下运行的个例还不多。作者尝试将MM5模式由UNIX系统移植到Windows系统并据此建立了微机业务应用系统。详细介绍了模式在移植过程中所要注意的几个问题、微机业务技术系统的结构及预报方案。 相似文献
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美国WRF模式的进展和应用前景 总被引:53,自引:3,他引:53
WRF(Weather Research Forecast)模式系统是美国气象界联合开发的新一代中尺度预报模式和同化系统,2004年6月对外发布了第二版和三维变分同化系统。这个模式采用高度模块化、并行化和分层设计技术,集成了迄今为止在中尺度方面的研究成果。模拟和实时预报试验表明,WRF模式系统在预报各种天气中都具有较好的性能,同时实现在线完全嵌套大气化学模式,不仅具有较好的天气预报水平,而且具有预报空气质量的能力,具有广阔的应用前景。 相似文献
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杭州市典型雨转雪天气成因及预报模型 总被引:1,自引:0,他引:1
利用2008—2018年的NCEP(1°×1°)再分析资料、常规气象观测资料和降雪加密观测资料,选出杭州地区10次典型的雨转雪天气过程,从大尺度环流背景和动力、水汽以及热力因子等物理量场结构方面展开研究,最终得出杭州冬季典型雨转雪天气的预报模型:①大尺度环流配置需满足能为雨转雪天气的形成提供有利的水汽、动力抬升以及中低层上暖下冷的逆温或等温层结条件;②水汽和动力因子等物理量须满足产生纯雪的特定条件;③杭州温度层结须为T_(2m)≤1.5℃、T_(925)≤-4.0℃、T_(850)≤0℃、T_(700)≤-1.0℃和T_(500)≤-10.0℃。此外,进一步补充了杭州可能产生大雪甚至暴雪量级降雪的特定条件。最终选取2019年初的2次典型降水过程进行预报回报检验。 相似文献
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数值天气预报模式产品在预报业务中的应用 总被引:7,自引:0,他引:7
介绍了数值预报模式产品性能的基本特征,讨论了模式产品误差的地理、季节和层次分布、不同尺度模式产品的可预报性、模式输出要素及物理量、指数的误差特点,并根据目前业务中常见的错误预报思路探讨了应用数值预报模式产品的合理思路,指出现代预报业务中预报员的作用。认为现代预报员应该了解几种基本的数值预报模式的特性及基本原理,集合各种模式的优点,综合本地预报经验,有效利用海量数值预报产品,做出更高质量的预报结果。 相似文献
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Atmospheric flow over complex terrain, particularly recirculation flows, greatly influences wind-turbine siting, forest-fire behaviour, and trace-gas and pollutant dispersion. However, there is a large uncertainty in the simulation of flow over complex topography, which is attributable to the type of turbulence model, the subgrid-scale (SGS) turbulence parametrization, terrain-following coordinates, and numerical errors in finite-difference methods. Here, we upgrade the large-eddy simulation module within the Weather Research and Forecasting model by incorporating the immersed-boundary method into the module to improve simulations of the flow and recirculation over complex terrain. Simulations over the Bolund Hill indicate improved mean absolute speed-up errors with respect to previous studies, as well an improved simulation of the recirculation zone behind the escarpment of the hill. With regard to the SGS parametrization, the Lagrangian-averaged scale-dependent Smagorinsky model performs better than the classic Smagorinsky model in reproducing both velocity and turbulent kinetic energy. A finer grid resolution also improves the strength of the recirculation in flow simulations, with a higher horizontal grid resolution improving simulations just behind the escarpment, and a higher vertical grid resolution improving results on the lee side of the hill. Our modelling approach has broad applications for the simulation of atmospheric flows over complex topography. 相似文献
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Junghan Kim Young Cheol Kwon Tae-Hun Kim 《Asia-Pacific Journal of Atmospheric Sciences》2018,54(1):403-412
The design and implementation of a high-performance Input/Output (I/O) library for the Korean Integrated Model (KIM, KIM-IO) is described in this paper. The KIM is a next-generation global operational model for the Korea Meteorological Administration (KMA). The horizontal discretization of KIM consists of the spectral-element method on the cubed-sphere grid. The KIM-IO is developed to be a consistent and efficient approach for input and output of essential data in this particular grid structure in a multiprocessing environment. The KIM-IO provides three main features, comprising the sequential I/O, parallel I/O, and I/O decomposition methods, and adopts user-friendly interfaces similar to the Network Common Data Form (NetCDF). The efficiency of the KIM-IO is verified using experiments to analyze the performance of its three features. The scalability is also verified by implementing the KIMIO in the KIM at a resolution of approximately 12 km using the 4th supercomputer of KMA. The experimental results show that both regular parallel I/O and sequential I/O undergo performance degradation with an increasing number of processes. However, the I/O decomposition method in the KIM-IO overcomes this degradation, leading to improvement in scalability. The results also indicate that with using the new I/O decomposition method, the KIM attains good parallel scalability up to Ο (100,000) cores. 相似文献