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采用FOXPLUS+2.10数据库管理系统和TRUE BASIC V2.03语言混合编程.整个程序用多模块状结构处理资料输入、修改、统计、预报、站点的增删改及预报结果输出,实现了中期旬降雨过程预报-H618法的电算自动化.程序具有功能性强、自动化程度高和通用性较强等优点. 相似文献
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目前,在专业气象服务中,台站积累了大量的预报模式指标（如入梅预报模式指标、出梅预报模式指标等）,随着计算机的广泛应用,所面对的实际问题是将这些预报工具编制成可操作的应用程序。模式指标中的指标因子,随着历史样本的变化,并不是固定不变的,如果每个模式指标的预报都要用一个命令程序描述,那将是十分繁琐复杂的事。解决此问题的较好办法是设计通用的模式指标预报程序。在此,笔者介绍一种比较简单适用的通用模式指标预报程序的设计方法。该方法是根据模式指标预报的一般规律,采用建立外部参量文件的办法,实现预报程序的“通用性”。用该方法设计的预报程序不仅适用于模式指标中指标因子变化的情况,而且适用于大量模式指标的预报。 相似文献
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国家气象局于1986年颁发的,安徽省气象局研制的《地面观测一月报表自动化系列技术》中,对于气表-1的统计和打印输出只限定两种打印机供选择,即M2024、3070其它型号的打印机则不能使用。这对该技术的进一步推广带来了局限。该技术是在MSDOS下开发,其专用字库,统计,打印等混在一起,要对此大容量的程序进行移植或修改很困难。加之国内尚无通用性较强的此类软件。为此,陕西省气象局于1989年4 相似文献
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采用VB6．0编程实现了多媒体系统演示程序，通过控制鼠标平滑移动及按钮动作，模拟控件事件的响应；引入MP3语音介绍，增强了程序的人性化效果。 相似文献
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基于遗传算法与共轭梯度法结合的四维同化方法 总被引：2，自引：1，他引：2
对气象资料的四维同化，采用共轭梯度算法和遗传算法，可以使两种方法相互补充，实验证明两者的结合能够增强搜索能力和收敛速度。在编写此程序时，采用标准化编程方法，使程序能够接近全自动化，从而缓解了编程的繁重劳动，减少程序中出现的错误。 相似文献
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制作数值天气预报或进行天气系统的诊断分析需要有气象要素的初始场。通常这种场是以给出有规则的网格点上的数据来表示的。这个工作可由计算机来做,称为客观分析方法。这个问题在国外早已开始研究,现在基本上已配套成龙。在我国这方面的研究工作也早已开展,并取得一定的成果。目前我国一些用于业务预报的数值天气预报模式均配有客观分析的程序。这些客观分析程序一般来说只能与本模式配套使用,不具有通用性。 相似文献
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High-resolution sedimentary paleoclimate proxy records offer the potential to expand the detection and analysis of decadal- to centennial-scale climate variability during recent millennia, particularly within regions where traditional high-resolution proxies may be short, sparse, or absent. However, time uncertainty in these records potentially limits a straightforward objective identification of broad-scale patterns of climate variability. Here, we describe a procedure for identifying common patterns of spatiotemporal variability from time uncertain sedimentary records. This approach, which we term Monte Carlo Empirical Orthogonal Function analysis, uses iterative age modeling and eigendecomposition of proxy time series to isolate common regional patterns and estimate uncertainties. As a test case, we apply this procedure to a diverse set of time-uncertain lacustrine proxy records from East Africa. We also perform a pseudoproxy experiment using climate model output to examine the ability of the method to extract shared anomalies given known signals. We discuss the advantages and disadvantages of our approach, including possible extensions of the technique. 相似文献
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该文在对平流扩散方程积分的基础上, 建立了对初始浓度有记忆力, 并对非相邻地区的浓度有感受力的箱格预报模式, 该模式的框架可用于各种时、空间尺度或多尺度的空气污染预测、预报.文中还定义了物理意义明确的空气污染潜势指数PPI以反映大气通风扩散稀释和干、湿沉降清除大气污染物的总能力, 结合天气预报模式和箱格预报模式则可进行空气污染潜势预报.给出了对源强和浓度监测要求灵活的空气污染指数PSI的预报公式和方法.在仅使用常规浓度监测资料的条件下, 检验了该文的基本方法, 其结果看来是可接受的. 相似文献
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Previous analysis has shown that inclusion of regional information improves at-site estimation of point rainfalls and makes it possible to obtain estimates at non-monitored sites. The basis for this analysis was a partial duration series (PDS) modelling of individual rainfall observations and use of regional prior distributions for the PDS-parameters in a Bayesian estimation procedure. The advantages of this theoretically satisfactory, but also somewhat complicated procedure are evaluated by means of a comparison with simplified procedures. These include modelling based on regional pooling of all point rainfall data into one sample from a common parent distribution and modelling with disregard of either the dependence between stations or the regional heterogeneity. The different models are analysed and compared with respect to the uncertainty of the predicted extreme events. 相似文献
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介绍了一个实用高效、简单易用的网络课件开发中文宏平台。重点说明了宏平台设计思路和开发该平台所涉及到的关键技术。同时,还介绍了使用宏平台进行课件网页编辑的具体步骤和课件页面的基本特征,以及利用该平台制作复杂网络课件页面的高效性。 相似文献
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地气温差对大气边界层热力交换起着极为重要的作用,对局地气候、城市边界层结构和大气污染有着重要影响,因此有必要对城市下垫面地气温差进行相应研究。本文以典型盆地城市成都为例,利用2014年成都市地表温度、气温逐时观测资料分析了该地区地气温差的变化特征,讨论了中尺度数值模式WRF (Weather Research and Forecasting Model)对盆地城市地气温差的模拟能力。结论表明:成都市平均地气温差为2.20℃,多分布在0～2℃区间,与地表温度和气温变化不同,温差春季最大,夏、冬季次之,秋季最小;各季节温差日变化大致相似,均为中午较大,夜间在0℃左右,但极值大小不同。利用WRF对成都市典型夏季晴天地气温差进行了模拟研究,对比分析三种常用陆面过程参数化方案的模拟结果,三种方案模拟的变化趋势均与观测吻合,其中Noah方案能较好的模拟成都市地气温差的变化特征,通过参数化方案的组合方式,改进了模式对地气温差的WRF模拟能力。 相似文献
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F. D’Andrea S. Tibaldi M. Blackburn G. Boer M. Déqué M. R. Dix B. Dugas L. Ferranti T. Iwasaki A. Kitoh V. Pope D. Randall E. Roeckner D. Strauss W. Stern H. Van den Dool D. Williamson 《Climate Dynamics》1998,14(6):385-407
As a part of the Atmospheric Model Intercomparison Project (AMIP), the behaviour of 15 general circulation models has been
analysed in order to diagnose and compare the ability of the different models in simulating Northern Hemisphere midlatitude
atmospheric blocking. In accordance with the established AMIP procedure, the 10-year model integrations were performed using
prescribed, time-evolving monthly mean observed SSTs spanning the period January 1979–December 1988. Atmospheric observational
data (ECMWF analyses) over the same period have been also used to verify the models results. The models involved in this comparison
represent a wide spectrum of model complexity, with different horizontal and vertical resolution, numerical techniques and
physical parametrizations, and exhibit large differences in blocking behaviour. Nevertheless, a few common features can be
found, such as the general tendency to underestimate both blocking frequency and the average duration of blocks. The problem
of the possible relationship between model blocking and model systematic errors has also been assessed, although without resorting
to ad-hoc numerical experimentation it is impossible to relate with certainty particular model deficiencies in representing
blocking to precise parts of the model formulation.
Received: 16 July 1997/Accepted: 20 October 1997 相似文献
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本文利用4个国内外先进的气候模式（国家气候中心、ECMWF、NCEP和JMA）业务预测数据,采用2种多模式集合方法（等权平均和超级集合）、3种降尺度方法（BP-CCA、EOF迭代、高相关回归集成）和3种统计方法（CCA、最优气候值、高相关回归集成）以及降尺度集成和降尺度-统计方法集成,分析了目前季节模式、多模式集合、降尺度、统计方法、降尺度-统计集合等目前常用气候预测技术对新疆夏季降水和冬季气温的业务预测能力。
研究表明,以上技术方法对新疆夏季降水和冬季气温的预测预测能力有较大差别。目前先进的气候业务模式的预测技巧普遍很低,多模式超级集合和降尺度方法的技巧常高于单个模式,并且最佳的降尺度方法通常技巧高于最佳多模式集合方法。同时,统计方法和降尺度方法的预测技巧通常较为接近,而对二者进行超级集合可以具有相对很高的预测技巧。此外,现有常用气候预测技术方法对新疆夏季降水和冬季气温的趋势有一定的预测能力,但对气候异常的空间分布基本无预测能力。建议新疆气候预测技术围绕统计和降尺度方法集合发展。 相似文献
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Retrospective satellite image data were evaluated for their ability to demonstrate the influence of center-pivot irrigation development in western Nebraska on spectral change and climate-related factors for the region. Periodic images of an albedo index and a normalized difference vegetation index (NDVI) were generated from calibrated Landsat multispectral scanner (MSS) data and used to monitor spectral changes associated with irrigation development from 1972 through 1986. The albedo index was not useful for monitoring irrigation development. For the NDVI, it was found that proportions of counties in irrigated agriculture, as discriminated by a threshold, were more highly correlated with reported ground estimates of irrigated agriculture than were county mean greenness values. A similar result was achieved when using coarse resolution Advanced Very High Resolution Radiometer (AVHRR) image data for estimating irrigated agriculture.The NDVI images were used to evaluate a procedure for making areal estimates of actual evapotranspiration (ET) volumes. Estimates of ET volumes for test counties, using reported ground acreages and corresponding standard crop coefficients, were correlated with the estimates of ET volume using crop coefficients scaled to NDVI values and pixel counts of crop areas. These county estimates were made under the assumption that soil water availability was unlimited. For nonirrigated vegetation, this may result in over-estimation of ET volumes. Ground information regarding crop types and acreages are required to derive the NDVI scaling factor. Potential ET, estimated with the Jensen-Haise model, is common to both methods. These results, achieved with both MSS and AVHRR data, show promise for providing climatologically important land surface information for regional and global climate models.TGS Technology, Inc. Work performed under U.S. Geological Survey contract 14-08-0001-22521; 相似文献
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The downscaling ability of a one-way nested regional climate model (RCM) is evaluated over a region subjected to strong surface forcing: the west of North America. The sensitivity of the results to the horizontal resolution jump and updating frequency of the lateral boundary conditions are also evaluated. In order to accomplish this, a perfect-model approach nicknamed the Big-Brother Experiment (BBE) was followed. The experimental protocol consists of first establishing a virtual-reality reference climate over a fairly large area by using the Canadian RCM with grid spacing of 45 km nested within NCEP analyses. The resolution of the simulated climate is then degraded to resemble that of operational general circulation models (GCM) or observation analyses by removing small scales; the filtered fields are then used to drive the same regional model, but over a smaller sub-area. This set-up permits a comparison between two simulations of the same RCM over a common region. The Big-Brother Experiment has been carried out for four winter months over the west coast of North America. The results show that complex topography and coastline have a strong positive impact on the downscaling ability of the one-way nesting technique. These surface forcings, found to be responsible for a large part of small-scale climate features, act primarily locally and yield good climate reproducibility. Precipitation over the Rocky Mountains region is a field in which such effect is found and for which the nesting technique displays significant downscaling ability. The best downscaling ability is obtained when the ratio of spatial resolution between the nested model and the nesting fields is less than 12, and when the update frequency is more than twice a day. Decreasing the spatial resolution jump from a ratio of 12 to six has more benefits on the climate reproducibility than a reduction of spatial resolution jump from two to one. Also, it is found that an update frequency of four times a day leads to a better downscaling than twice a day when a ratio of spatial resolution of one is used. On the other hand, no improvement was found by using high-temporal resolution when the driving fields were degraded in terms of spatial resolution. 相似文献
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Andrew G. Marshall Debra Hudson Matthew C. Wheeler Harry H. Hendon Oscar Alves 《Climate Dynamics》2011,37(11-12):2129-2141
We assess the ability of the Predictive Ocean Atmosphere Model for Australia (POAMA) to simulate and predict weekly rainfall associated with the MJO using a 27-year hindcast dataset. After an initial 2-week atmospheric adjustment, the POAMA model is shown to simulate well, both in pattern and in intensity, the weekly-mean rainfall variation associated with the evolution of the MJO over the tropical Indo-Pacific. The simulation is most realistic in December?CFebruary (austral summer) and least realistic in March?CMay (austral autumn). Regionally, the most problematic area is the Maritime Continent, which is a common problem area in other models. Coupled with our previous demonstration of the ability of POAMA to predict the evolution of the large-scale structure of the MJO for up to about 3?weeks, this ability to simulate the regional rainfall evolution associated with the MJO translates to enhanced predictability of rainfall regionally throughout much of the tropical Indo-Pacific when the MJO is present in the initial conditions during October?CMarch. We also demonstrate enhanced prediction skill of rainfall at up to 3?weeks lead time over the north-east Pacific and north Atlantic, which are areas of pronounced teleconnections excited by the MJO-modulation of tropical Indo-Pacific rainfall. Failure to simulate and predict the modulation of rainfall in such places as the Maritime Continent and tropical Australia by the MJO indicates, however, there is still much room for improvement of the prediction of the MJO and its teleconnections. 相似文献