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1.
南海热带气旋路径集合预报试验   总被引:17,自引:12,他引:5       下载免费PDF全文
利用3种不同模式的初始资料,通过它们生成得到16个不同的初始场,分别对2004年南海及其周边地区9个热带气旋个例进行集合预报试验,最后筛选得到了7个南海热带气旋初值集合成员,由此初步探讨了南海热带气旋初值集合成员的生成方法。结果表明,采用不同模式的初始资料生成得到初值集合成员的方法用于集合预报,对南海热带气旋路径预报有一些明显的改进。  相似文献   
2.
国家气象中心中期集合预报系统概况   总被引:5,自引:0,他引:5  
随着对大气初值及数值模式存在不确定性的认识以及计算机技术的飞速发展,集合预报已经成为数值预报发展的重要方向之一。本文介绍集合预报的基本概念及初值扰动的特点和国家气象中心集合预报系统的概况。  相似文献   
3.
应用LASGREMM模式 ,对淇、卫河流域“96·8”致洪暴雨过程进行了模拟预报分析。结果表明 ,LAS GREM模式不仅能较准确地预报淇、卫河流域暴雨落区 ,而且可以进一步分析天气过程的特点及演变情况  相似文献   
4.
Based on Chen et al. (2006), the scheme of the combination of the pentad-mean zonal height departure nonlinear prediction with the T42L9 model prediction was designed, in which the pentad zonal heights at all the 12-initial-value-input isobar levels from 50 hPa to 1000 hPa except 200, 300, 500, and 700 hPa were derived from nonlinear forecasts of the four levels by means of a good correlation between neighboring levels. Then the above pentad zonal heights at 12 isobar-levels were transformed to the spectrum coefficients of the temperature at each integration step of T42L9 model. At last, the nudging was made. On account of a variety of error accumulation, the pentad zonal components of the monthly height at isobar levels output by T42L9 model were replaced by the corresponding nonlinear results once more when integration was over. Multiple case experiments showed that such combination of two kinds of prediction made an improvement in the wave component as a result of wave-flow nonlinear interaction while reducing the systematical forecast errors. Namely the monthly-mean height anomaly correlation coefficients over the high- and mid-latitudes of the Northern Hemisphere, over the Southern Hemisphere and over the globe increased respectively from 0.249 to 0.347, from 0.286 to 0.387, and from 0.343 to 0.414 (relative changes of 31.5%, 41.0%, and 18.3%). The monthly-mean root-mean-square error (RMSE) of T42L9 model over the three areas was considerably decreased, the relative change over the globe reached 44.2%. The monthly-mean anomaly correlation coefficients of wave 4-9 over the areas were up to 0.392, 0.200, and 0.295, with the relative change of 53.8%, 94.1%, and 61.2%, and correspondingly their RMSEs were decreased respectively with the rate of 8.5%, 6.3%, and 8.1%. At the same time the monthly-mean pattern of parts of cases were presented better.  相似文献   
5.
Systematic errors have recently been founded to be distinct in the zonal mean component forecasts, which account for a large portion of the total monthly-mean forecast errors. To overcome the difficulty of numerical model, the monthly pentad-riean nonlinear dynamic regional prediction models of the zonal mean geopotential height at 200, 300, 500, and 700 hPa based on a large number of historical data (NCEP/NCAR reanalysis data) were constituted by employing the local approximation of the phase space reconstruction theory and nonlinear spatio-temporal series prediction method. The 12-month forecast experiments of 1996 indicated that the results of the nonlinear model are better than those of the persistent, climatic prediction, and T42L9 model either over the high- and mid-latitude areas of the Northern and Southern Hemispheres or the tropical area. The root-mean-square of the monthly-mean height of T42L9 model was considerably decreased with a change of 30.4%, 26.6%, 82.6%, and 39.4%, respectively, over the high- and mid-latitudes of the Northern Hemisphere, over the high- and mid-latitudes of the Southern Hemisphere, over the tropics and over the globe, and also the corresponding anomaly correlation coefficients over the four areas were respectively increased by 0.306-0.312, 0.304-0.429, 0.739-0.746, and 0.360-0.400 (averagely a relative change of 11.0% over the globe) by nonlinear correction after integration, implying that the forecasts given by nonlinear model include more useful information than those of T42L9 model.  相似文献   
6.
河西走廊东部近50年沙尘暴气候预测研究   总被引:9,自引:2,他引:7  
应用甘肃省河西走廊东部武威市5站(乌鞘岭、古浪、永昌、凉州区、民勤)近50年月、年气象资料和沙尘暴个例,详细分析了沙尘暴产生的气候背景和气候影响因子。在分析二十多种气象要素的基础上,做出沙尘暴不同时间、不同范围的日数和强度预报方程。研究表明:河西走廊东部的沙尘暴是武威市北部干旱气候、丰富的地表沙源与大风天气相互作用的结果;沙尘暴日数与该市中北部冬春季的气温、年降雨量和大风日数有关;沙尘暴强度与武威市前期的干旱、异常增温、强大风日数有关。  相似文献   
7.
    
The approach of getting useful information of monthly dynamical prediction from ensemble forecasts is studied. The extended range ensemble forecasts (8 members, the initial perturbations of the lagged average forecast (LAF)(0000, 0600, 1200 and 1800 GMT in two consecutive days) of the 500 hPa height field with the global spectral model (T63L16) from January to May 1997 are provided by the National Climate Center of China. The relationship between the spread of ensemble measured by root–mean–square deviation of ensemble member from ensemble mean and forecast skill (the anomaly correlation or the root–mean–square distance between the ensemble mean forecast and the observation) is significant. The spread of ensemble can evaluate the useful forecast days N for the best estimate of 30 days mean. Thus, a weighted mean approach based on ensemble spread is put forward for monthly dynamical prediction. The anomaly correlation of the weighted monthly mean by the ensemble spread is higher than that of both the arithmetic mean and the linear weighted mean. Better results of the monthly mean circulation and anomaly are obtained from the ensemble spread weighted mean. Supported by the Excellent National State Key Laboratory Project (49823002), the National Key Project ‘Study on Chinese Short-Term Climate Forecast System’ (96-908-02) and IAP Innovation Foundation (8-1308). The data were provided through the National Climate Center of China. The authors wish to thank Ms. Chen Lijuan for her assistance.  相似文献   
8.
Studies on the seasonal to extraseasonal climate prediction at the Institute of Atmospheric Physics (IAP) in recent years were reviewed. The first short-term climate prediction experiment was carried out based on the atmospheric general circulation model (AGCM) coupled to a tropical Pacific oceanic general circulation model (OGCM). In 1997, an ENSO prediction system including an oceanic initialization scheme was set up. At the same time, researches on the SST-induced climate predictability over East Asia were made. Based on the biennial signal in the interannual climate variability, an effective method was proposed for correcting the model predicted results recently. In order to consider the impacts of the initial soil mois ture anomalies, an empirical scheme was designed to compute the soil moisture by use of the atmospheric quantities like temperature, precipitation, and so on. Sets of prediction experiments were carried out to study the impacts of SST and the initial atmospheric conditions on the flood occurring over China in 1998.  相似文献   
9.
The numerical simulations,hindcasts and verifications of the tropical Pacific sea surfacetemperature anomaly(SSTA)have been conducted by using a dynamical tropical Pacific ocean-atmosphere coupled model named NCCo.The results showed that the model had performedreasonable simulations of the major El Nino episodes in the history,and the model forecast skill in1990s had been significantly improved.NCCo model has been used to predict the tropical PacificSSTA since January 1997.The comparisons between predictions and observations indicated thatthe occurrence,evolution and ending of the 1997/1998 El Nino episode have been predicted fairlywell by using this model.Also,the La Nina episode that began in the autumn of 1998 and thedeveloping tendency of the tropical Pacific SSTA during the year 1999 have been predictedsuccessfully.The forecast skills of NCCo model during the 1997-1999 El Nino and La Ninaevents are above 0.5 at 0—14 lead months.  相似文献   
10.
    
An effective method was proposed for correcting the seasonal—interannual prediction of the summer climate anomaly. The predictive skill can be substantially improved by applying the method to the seasonal—interannual prediction carried out by a coupled ocean—atmosphere model. Thus the method has the potential to improve the operational summer climate predictions. This research was supported by the National Key Programme for Developing Basic Sciences under Contract G1998040905-2 and the key project “ The Analytical Study on the Seasonal and Interannual Variability of the General Atmospheric Circulation (1998-2001)” of National Natural Science Foundation of China under Contract 49735160.  相似文献   
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