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ＴｈｅＷａｔｅｒ－ＢｅａｒｉｎｇＮｕｍｅｒｉｃａｌＭｏｄｅｌａｎｄＩｔｓＯｐｅｒａｔｉｏｎａｌＦｏｒｅｃａｓｔｉｎｇＥｘｐｅｒｉｍｅｎｔｓＰａｒｔＩ：ＴｈｅＷａｔｅｒ－ＢｅａｒｉｎｇＮｕｍｅｒｉｃａｌＭｏｄｅｌＸｉａＤａｑｉｎｇ（夏大庆）ａｎｄＸｕＹ... 相似文献
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提高月预报业务水平的动力相似集合方法 总被引：3，自引：0，他引：3
针对基于大气环流模式的月预报问题,提出了一种能有效减小预报误差并提高预报技巧的动力相似集合预报新方法。该方法着眼于动力模式与统计经验的内在结合,在模式积分过程中通过提取大气环流历史相似性信息,对模式误差进行参数化处理,形成多个时变的相似强迫量来扰动生成预报的集合成员。将这一集合新方法应用到中国国家气候中心业务大气环流模式(BCC AGCM1.0),一组10 a准业务环境下回报试验结果显示,相比于业务集合预报,动力相似集合预报方法能有效改进模式对于大气环流的纬向平均、超长波和长波预报,从而有效提高了月平均环流预报技巧(几乎达到业务可用标准)和逐日环流预报技巧,并显著降低了预报误差,合理增加集合离散度,使二者配置关系得以改善,有望在业务预报中应用。 相似文献
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介绍了在MM5模式基础上建立起来的辽宁省热带气旋模式预报业务系统及2005年的预报情况。系统以T213L31产品为背景场和侧边界,初始场中同化了常规探空报、地面报及一些卫星反演资料,模式的初值中还嵌入人造热带气旋进行模式运算。系统每日自动运行2次;模式输出结果经后处理后,编写到通用绘图软件GrADs中,以图形显示,并在沈阳区域气象中心局域网的中尺度数值预报网页上显示。2005年汛期热带气旋预报表明,系统对热带气旋的路径和暴雨的预报效果较好。 相似文献
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以业务应用为目标,开展雷达反射率三维拼图观测资料在北方区域数值预报系统中的同化应用研究。采用雷达反射率间接同化方法同化北方雷达反射率拼图观测资料,重点关注其对降水、湿度、温度及风的预报能力影响。首先,基于2017年8月雷达拼图观测资料批量同化和对比试验,对雷达拼图资料同化应用效果进行定量评估,结果表明雷达拼图资料同化虽然加大了地面风场预报误差,但在降水预报和湿度、温度预报等方面有明显的改善作用。其次,选择在业务中预报难度较大的强降水个例开展分析研究,分析表明:（1）同化雷达拼图观测资料有效提高了模式降水预报性能,临近降水发生的循环起报时次预报效果更好;（2）对于短时间多次强降水过程发生的预报,循环同化雷达拼图资料可及时弥补模式中由于前次降水导致的水汽、能量等消耗及热/动力条件削弱,持续支持降水系统发展。最后,通过考察雷达反射率的不同同化方案,发现同化反演水凝物或者估计水汽均能改善模式降水预报性能,但是同化估计水汽对降水预报性能的改善更为明显,联合使用两方案能同时对水凝物分布、热力场等进行调整,可提高模式降水预报性能。 相似文献
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The purpose of this study is to investigate the effectiveness of two different ensemble forecasting (EF) techniques–the lagged-averaged forecast (LAF) and the breeding of growing modes (BGM). In the BGM experiments, the vortex and the environment are perturbed separately (named BGMV and BGME). Tropical cyclone (TC) motions in two difficult situations are studied: a large vortex interacting with its environment, and an apparent binary interaction. The former is Typhoon Yancy and the latter involves Typhoon Ed and super Typhoon Flo, all occurring during the Tropical Cyclone Motion Experiment TCM- 90. The model used is the baroclinic model of the University of New South Wales. The lateral boundary tendencies are computed from atmospheric analysis data. Only the relative skill of the ensemble forecast mean over the control run is used to evaluate the effectiveness of the EF methods, although the EF technique is also used to quantify forecast uncertainty in some studies. In the case of Yancy, the ensemble mean forecasts of each of the three methodologies are better than that of the control, with LAF being the best. The mean track of the LAF is close to the best track, and it predicts landfall over Taiwan. The improvements in LAF and the full BGM where both the environment and vortex are perturbed suggest the importance of combining the perturbation of the vortex and environment when the interaction between the two is appreciable. In the binary interaction case of Ed and Flo, the forecasts of Ed appear to be insensitive to perturbations of the environment and/or the vortex, which apparently results from erroneous forecasts by the model of the interaction between the subtropical ridge and Ed, as well as from the interaction between the two typhoons, thus reducing the effectiveness of the EF technique. This conclusion is reached through sensitivity experiments on the domain of the model and by adding or eliminating certain features in the model atmosphere. Nevertheless, the forecast tracks in some of the cases are improved over that of the control. On the other hand, the EF technique has little impact on the forecasts of Flo because the control forecast is already very close to the best track. The study provides a basis for the future development of the EF technique. The limitations of this study are also addressed. For example, the above results are based on a small sample, and the study is actually a simulation, which is different than operational forecasting. Further tests of these EF techniques are proposed. 相似文献
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Summary This paper examines the performance of several atmospheric instability indices for operational hail forecasting in the Greek National Hail Suppression Program (GNHSP). These indices are part of the adopted forecasting procedure in the GNHSP, which also involves a synoptic index of convection and a synoptic scale typing scheme. The assessment of the indices is accomplished objectively through a multivariate statistical technique, namely factor analysis. The analysis resulted in grouping of the indices into three factors. The indices with high loading and scores are considered to best detect convection for hail forecasting in the GNHSP.With 4 Figures 相似文献
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雷达和卫星资料在淮河流域暴雨实时数值预报试验中的应用 总被引：11，自引：1，他引：10
本文在前一工作「文献」基础上,将雷达和卫星资料计入ＰＳＵ／ＮＣＡＲ ＭＭ４中尺度数值模式,对１９９８年６月底和７月初的二次淮河流域暴雨过程,进行了帝时数值预报试验,结果表明,计入雷达和卫星资料的敏感性试验效果,比不计入该二种资料的控制试验有较好的明显的改进,文中还分析比较了控制试验（ＣＴＥ）和敏感试验（ＳＴＥ）每三小时的雨量和散度场,、垂直运动场及高度场的变化。结果显示,ＳＴＥ的雨量、产生暴雨的切变丝低涡系统以及散度和上升运动等的增强时间都比ＣＴＥ提前,因此,２４小时雨量与实况比较接近。 相似文献
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基于增长模繁殖法的集合预报试验 总被引：5，自引：0，他引：5
利用微机版本的T63L9全球谱模式,首先进行了用增长模繁殖法(BGM)制作集合预报的方案设计,然后用确定的方案进行了中期数值预报的集合预报试验。繁殖循环的初始扰动为T63L9谱模式各层24 h预报的均方根误差乘随机数,该随机数服从[-1, 1]区间上的均匀分布,繁殖循环每12 h 1次,繁殖循环的周期为3 d,集合成员为9个。结果表明:在1~8 d的预报中,集合预报可以比控制预报的时效延长1 d,集合预报无论是距平相关系数还是预报均方根误差都明显优于控制预报,集合预报对形势场的预报较控制预报更为接近实况分析场。 相似文献
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Paul Joe Cliff Crozier Norman Donaldson Dave Etkin Erik Brun Steve Clodman 《大气与海洋》2013,51(2):249-302
Abstract Summer severe weather (SSW) can strike suddenly and unexpectedly with disastrous consequences for human activity. Considerable progress has been made in the past ten years in the operational forecasting of SSW. Traditionally, SSW was defined to consist of tornadoes, strong winds, hail, lightning and heavy rain. Hazardous types of strong winds have recently been expanded to include microbursts, macrobursts and surfacing rear inflow jet damage behind mesoscale convective systems. Doppler radar was used to relate surface damage to the appropriate atmospheric phenomena, first diagnostically and then prognostically. This improvement in classification has fedback to and improved the forecast process. Concurrent progress has been made in the use of synoptic observations. The concept of helical wind profiles and improved knowledge of the role of dry mid‐level air has improved the forecasting of tornadoes and strong gusty winds. Moisture flux convergence, derived from surface measurements, shows great promise in identifying areas of storm initiation. Satellite imagery has been used to identify dynamical atmospheric boundaries. Numerical modelling of the interaction of environmental wind profiles and individual thunderstorms has greatly contributed to the understanding of SSW. Studies of spatial and temporal patterns of lightning, both specific cases and climatology, contribute to the forecasting of severe storms. Polarization radar results have shown progress in separating the signals of hail from those of rain and in the improved measurement of heavy rainfalls. Radar observation of clear air boundaries and their interactions show potential for the forecasting of thunderstorm initiation. Though not traditionally considered part of SSW, hurricanes that evolve into extra‐tropical storms share many of the same hazardous features. The progress in computing, communications and display technologies has also made substantial contributions to operational forecasting and to the dissemination of weather warnings. 相似文献
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我国台风预报业务的现状及思考 总被引：15，自引：1，他引：14
随着数值预报模式和技术以及综合探测体系的不断进步和完善,自20世纪90年代以来我国台风业务预报取得了长足的进步,特别是台风路径业务预报水平进展显著,目前基本达到国际先进水平。通过对我国及国际台风/飓风业务预报现状的回顾,分析了目前我国台风业务预报中存在的主要问题、业务预报难点和亟待解决的科学问题,同时展望了我国台风业务预报在全球气候变化条件下,以及日益增长的国家防灾减灾需求形势下所面临的挑战,并对我国台风业务预报的未来发展做出了一些粗浅的思考,提出了改进我国台风业务预报的相关建议措施。 相似文献
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兰州区域气象中心暴雨增强数值预报业务系统包括资料处理，质量控制、客观分析、模式预报、图形处理及显示、评分检验和作业流程控制等。由于业务系统采用了先进的并行计算技术，同时对模式结构和部分物理过程进行了改进，使模式的分辨率得到了大幅度的提高。 相似文献
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目前,集合预报已成为天气预报业务的主要支撑。然而,由于数值模式本身的限制与不完善以及集合系统存在初值扰动、集合大小等方面的局限,常存在预报偏差。不同预报模式通常具有不同的物理过程参数化方案、初始条件等,导致其预报能力各有不同。为此,如何纠正预报偏差以及如何充分有效地利用不同模式的预报信息以获得更加准确的天气预报广受关注。近年来,利用统计理论与预报诊断,基于多个集合预报系统的多模式集成预报技术得到快速发展,已成为有效消除预报偏差从而提高天气预报技巧的一种统计后处理方法。针对气温、降水和风3个最基本的地面气象要素,首先依据预报形式将应用范围较广的简单集合平均、消除偏差集合平均、超级集合、贝叶斯模式平均、集合模式输出统计等加权或等权平均多模式集成技术,分成确定性预报和概率预报两大类,并做系统介绍。最后,讨论使用和发展多模式集成技术需要关注的问题,包括考虑参与集成的模式个数、发展降水及风速分级预报模型和发展基于机器学习的多模式集成新技术。 相似文献
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该文总结回顾了中央气象台近年来的天气预报业务技术进展。天气预报质量的历史演变显示了预报业务水平的提高, 这种业务能力的提高既反映了预报技术的发展, 也带来了天气预报业务的变化。对业务天气预报中各种预报技术应用进展的分析表明:数值预报在天气预报业务能力提高中发挥着重要的基础性作用; 同时, 基于对不同尺度天气影响系统发展演变过程深入认识的基础上, 天气学的预报方法依然是预报业务中的重要技术方法; 动力诊断预报已成为灾害性天气预报中的重要手段之一, 数值预报产品的解释应用是实现气象要素精细定量预报的技术途径。 相似文献
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基于BPSO-NBayes的雷暴释用预报技术研究 总被引：1，自引：1，他引：0
提出了一种新的雷暴预报法,即二进制粒子群-朴素贝叶斯分类器(Binary Particle Swarm Optimization-Naive Bayesian Classifiers,BPSO-NBayes)方法,以福州、连城、宁波3站为例,对使用T511数值预报产品站点的雷暴释用预报技术进行研究。利用2010—2014年T511数值预报产品和单站观测资料,使用BPSO-NBayes方法,建立了0~72 h雷暴预报模型,并与Fisher判别准则和Bayes判别准则进行比较。预报结果表明,BPSO-NBayes模型临界成功指数都在0.29以上,平均值达到0.33以上,是3种方法中最好的,空报率都在0.59以下,漏报率在0.60以下,而且变化幅度很小。BPSO-NBayes模型明显优于Fisher判别准则和Bayes判别准则,具有良好的稳定性和预报能力。 相似文献
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复杂地形导致近地层风场时空变化大,是影响风电场短期风电功率预测准确率的重要因素。为此,基于中尺度数值预报模式和微尺度计算流体力学模式,建立了风电场短期风电功率动力降尺度预测系统。该系统由中尺度数值预报模式、微尺度风场基础数据库、风电功率预测集成系统组成,能够预测复杂地形风电场中每台风电机组未来72 h逐15 min的发电量。提高了复杂地形风场发电功率预测准确率,同时还可以在上报电网的风电功率预测结果中考虑运行维护计划和限电等因素对实际并网功率的影响。2014年7月-2015年1月的业务预测试验表明,风电场短期风电功率动力降尺度预测系统的月预测相对误差均小于0.2,满足中国国家电网对风电功率预测误差和时效性的业务要求。动力降尺度技术不受具体项目地形复杂程度和历史观测数据样本量的限制,可以在新建风电场中推广应用,具备实际的可操作性。 相似文献
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S. A. Hsu 《Boundary-Layer Meteorology》1979,16(1):93-98
Variation exists in the maximum mixing height (MMH) across the coastal zone because of major differences in heat capacity between land and sea. By assuming that synoptic and microscale effects are all small as compared to the contribution from mesoscale temperature differences, a model is proposed to explain this variation. The model states that the variation of the MMH across the coastal zone is due primarily and is linearly proportional to the difference in maximum temperature between land and sea. Since the MMH is one of the most important parameters in the computation of distribution and concentration of aerosols, water vapor, and pollutants, a simple equation is also provided for the operational forecasting of the MMH or the mixing height over the sea. All inputs into the equation are routinely available. The model has been verified by available data and a relevant field experiment. 相似文献