数值预报产品统计释用技术在热带气旋路径客观预报中的应用

首先对应用数值预报产品统计释脾技术的效果进行了统计。结果表明,数值预报产品和技术的应用改善了热带气旋路径客观预报中预测因子的预报能力,提高了模式的预报技巧并拓展了有效预报时效。继而对热带气旋路径客观预报中若干统计释用技术问题进行了讨论,并指出：在应用数值预报产品构造热带气旋路径客观预报模式时,采用大样本资料和完全预报方法,细心构造反映各种天气系统特征和物理量场的预报因子,应用多时刻产品并对ＮＷＰ产     

SOME ASPECTS OF OBJECTIVE FORECASTING OF TROPICAL CYCLONE MOTION

As shown in a statistical analysis of the relationship between environmental fields at varied timeand tropical cyclone motion, the forecasting ability of the initisl environmental field predictors for tropical cyclone motion decreases with the increase of valid time period of forecast;it is higher with these predictors at a fUture time than at an initial time. The work also indicates that for the tropical cyclone motion over a given period of valid forecast, better predictors appear at times mostly differing from thevalid periods; for periods at 48-120 h the environmental predictors at 48-72 h are more capable of forecasting. With statistical interpretation of NWP products, a predictive model for tropical cyclone motionis superior in performance over a statistical forecasting model that employes predictors of the initial field in the basic framework. The concluding remarks can be used as reference in the construction of an objective prediction model for tropical cyclone motion.     

数值预报产品统计释用技术在热带气旋路径客观预报中的应用

首先对应用数值预报产品统计释用技术的效果进行了统计,结果表明,数值预报产品统计释用技术的应用改善了热带气旋路径客观预报中预报因子的预报能力,提高了模式的预报技巧并拓展了有效预报时效。继而对热带气旋路径客观预报中若干统计释用技术问题进行了讨论,并指出：在应用数值预报产品构造热带气旋路径客观预报模式时,采用大样本资料和完全预报方法,细心构造反映各种天气系统特征和物理量场的预报因子,应用多时刻ＮＷＰ产品并对ＮＷＰ产品进行统计订正。对多种预报模式的预报结果进行综合集成等技术是提高预报技巧和稳定性的有效途径。     

热带气旋定量降水预报的动力相似方案

该文提出一个热带气旋定量降水预报(QPF) 的动力相似方案。方案应用热带气旋初始参数、历史过程的天气形势场和物理量场及数值预报产品, 构造预报区域内当前时刻至未来时刻环境要素场的多元客观相似判据。通过定义非线性的相似指数综合评估历史热带气旋样本与预报热带气旋在多元判据下的连续动态相似程度, 以此找到相似样本。应用相似样本的历史降水量记录进行相似指数的权重综合, 得到热带气旋未来6~48 h降水量的定点、定量预报值。预报试验表明该方案具有一定的预报技巧。     

THE OBJE CTIVE ANALOGUE PREDICTION MODEL FOR TROPICAL CYCLONE TRACK WITH COMPREHENSIVE ASSESSMENT OF THE ENVIRONMENT

An objective analogue prediction model for tropical cyclone (TC) track is put forward that comprehensively assesses the environmental field. With the parameters of the tropical cyclone and environmental field at initial and future time, objective analogue criteria are set up in the model. Analogous samples are recognized by comprehensive assessment to historical TC cases for similarity with multivariate criteria,using non-linear analogue indexes especially defined for the purpose. When the historical tracks are coordinateconverted and weighted with reference to analogue indexes,forecast tracks are determined. As shown in model verification and forecast experiments, the model has forecasting skill.     

2006年6—8月T213与ECMWF模式中期预报性能检验

6—8月是我国高温干旱、暴雨洪涝等气象灾害最为严重的季节。该季节天气系统变化快，活动剧烈，天气预报难度大，最能考验数值预报模式的预报性能。为更好地应用T213模式中期预报产品，对2006年6—8月T213模式中期96小时数值预报产品进行了统计和天气学检验，并与ECMWF模式同类产品进行了对比分析。结果表明，T213和ECMWF模式对中高纬度大型环流的调整、副高及850hPa温度等均有较好的预报能力，对台风路径也都有一定的预报能力，但T213模式台风移速预报过快，登陆偏早，而ECMWF模式预报相反。     

2002年西北太平洋和南海热带气旋路径主客观预报评价

利用目前中央气象台热带气旋路径实时业务预报中使用的各种主客观预报产品资料，对2002年西北太平洋和南海热带气旋路径实时业务预报中的主客观预报进行对比分析检验。结果显示：虽然在整体上主观预报要优于客观模式的结果，但客观模式的预报能力已接近主观预报，有时甚至还好于主观预报，特别是48小时以上时效的客观模式较主观预报具有一定的优势；而在客观模式中，全球模式优于台风模式；热带气旋路径数值模式产品的使用对提高热带气旋路径业务预报水平具有十分重要的作用。     

Tropical cyclone track predictability

Summary In this study an attempt is made to estimate theinherent limits to tropical cyclone mean absolute track position errors out to 72 hours ahead and to compare these estimates with the position errors currently being obtained inpractice at weather centres around the world. A knowledge of the magnitude of the difference between the lower limit to predictability and that being achieved with state-of-the-art numerical weather prediction (NWP) models is of vital importance. A small difference would indicate that there is little further need for continued initiatives in the prediction of tropical cyclone tracks. On the other hand, a large difference would imply either that the problem requires continued emphasis or if there has been no significant trend towards reducing the forecast track errors, that present research and development techniques need to be extended or new procedures developed.It was found that the difference between the inherent and practical limits of tropical cyclone track position errors is presently about 35 to 40 per cent for advanced baroclinic NWP systems, a moderate to large difference, and one that is almost invariant between tropical cyclone basins. For simpler models, such as barotropic models, the difference is closer to 45 per cent but is again almost invariant. As far as the authors are aware, these are the first estimates of the lower bounds of tropical cyclone track predictability. Finally, very recent research studies with emerging range of high quality data, high density data sources, improved models and new data assimilation techniques suggest that the difference possibly is now down to about 30 to 35 per cent. This value is encouragingly small but still large enough to continue active research programs in improving tropical cyclone motion prediction. Much of the forecast track errors now come from major forecast errors associated with tropical cyclones that follow erratic tracks.With 3 Figures     

热带气旋路径客观预报的若干问题

对多时刻环境因子与热带气旋路径相关的统计分析表明，初始时刻环境场因子对热带气旋路径的预报能力随预报时效的增长而下降；未来时刻环境因子的预报能力高于初始时刻环境场因子；对于一定预报时效的热带气旋路径，具有较高预报能力环境场因子出现时刻大多不与预报时效同时刻；对于４８￣１２０小时的预报时效，初始时刻后４８－７２小时的环境场因子具有较高的预报能力。对ＮＷＰ产品进行统计释用的热带气旋路径预报模式优于用初如     

T63模式对暴雨短期预报能力的分析检验

利用Ｔ６３模式的５００ｈＰａ数值形势预报图和客观分析实况图，对１９９４年７－９月我国出现的１２次较大范围暴－大暴雨天气过程的影响天气系统进行了预报能力的分析检验，并分析了产生误差的原因，所得结果有利于数值预报产品的释用及实时预报业务。     

Skill of synthetic superensemble hurricane forecasts for the Canadian maritime provinces

Summary From 1994 to 2003, fifty-five tropical cyclones entered the Canadian Hurricane Centre (CHC) Response Zone, or about 42% of all named Atlantic tropical cyclones in this ten-year period, and 2003 was the fourth consecutive year for a tropical cyclone to make landfall in Canada. The CHC forecasts all tropical cyclones that enter the CHC Response Zone and assumes the lead in forecasting once the cyclone enters its area of forecast responsibility. This study acknowledges the challenges of forecasting such tropical cyclones at extratropical latitudes. If a tropical cyclone has been declared extratropical, global models may no longer use vortex bogussing to carry the cyclone, and even if it is modeled, large model errors often result. The purpose of this study is to develop a new version of the Florida State University (FSU) hurricane superensemble with greater skill in tracking tropical cyclones, especially at extratropical latitudes. This has been achieved from the development of the synthetic superensemble, which is similar to the operational version of the multi-model superensemble that is used at FSU. The synthetic superensemble differs in that is has a larger set of member models consisting of regular member models, synthetic versions of these models, and the operational superensemble and its synthetic version. This synthetic superensemble is being used here to forecast hurricane tracks from the 2001, 2002, and 2003 hurricane seasons. The track forecasts from this method have generally less error than those of the member models, the operational superensemble, and the ensemble mean. This study shows that the synthetic superensemble performs consistently well and would be an asset to operational hurricane track forecasting.     

Western North Pacific Tropical Cyclone Intensity Guidance Evaluations Using an Alternative Verification Technique

In this study, six intensity forecast guidance techniques from the East China Regional Meteorological Center are verified for the 2008 and 2009 typhoon seasons through an alternative forecast verification technique. This technique is used to verify intensity forecasts if those forecasts call for a typhoon to dissipate or if the real typhoon dissipates. Using a contingency table, skill scores, chance, and probabilities are computed. It is shown that the skill of the six tropical cyclone intensity guidance techniques was highest for the 12-h forecasts, while the lowest skill of all the six models did not occur in 72-h forecasting. For both the 2008 and 2009 seasons, the average probabilities of the forecast intensity having a small error (6 m s-1) tended to decrease steadily. Some of the intensity forecasts had small skill scores, but the associated probabilities of the forecast intensity errors > 15 m s-1 were not the highest.     

热带气旋路径客观综合集成预报方法的研制

在正确评估我国现有发报的７种客观预报方法性能的基础上，分别对西北太平洋，东海，南海３个责任海区，采用典型相关，条件概率组合，新回归系数估计法等多种统计模型，建立包括数值预报产品在内的热带气旋路径的综合集成预报方法。     

THE ENSEMBLE FORECASTING OF TROPICAL CYCLONE MOTION I：USING A PRIMITIVE EQUATION BAROTROPIC MODEL

1INTRODUCTIONErrorsofnumericalforecastingcomprisethoseintheinitialvalue,modelandcomputationandthefirstkindoferrorbecomesmoreandmoreoutstandingwiththeon-goingdevelopmentofcomputersandnumericalmodels.Subjecttoavailableobservationmeans,therealatmosphereisanythingbutapproximatelymeasured.Meanwhile,oneshouldpayattentiontothepossibility,assuggestedbyLorenz[1],thatanyslightdifferencesduringtheinitialstatemayleadtoresultsthatturnouttobetotallydissimilarfromwhatwouldbeexpectedotherwise,asfarasdefi…     

热带气旋路径趋势数值预报的试验研究

给出了一个嵌套于欧洲中期天气预报中心全球谱模式中的套网格模式，用于预报热带气旋路径趋势，提出了一种以欧洲中期天气预报中心提供的时距为24小时的预报场为基础的“接力预报”方法；设计了五种不同的“接力预报”方案；并对8507号和8509号两个热带气旋就各种不同预报方案进行了数值预报试验。结果表明，本模式对热带气旋路径趋势具有较强的预报能力，对疑难路径也具有一定的预报能力，为开展热带气旋的路径趋势预报提供了一个新的途径。文中还对影响热带气旋路径趋势的一些主要因子结合各预报结果进行了分析，为模式尽早投入业务提供了一定的依据。     

2004年汛期(5～9月)主客观降水预报检验

随着气象事业的发展，天气预报的质量越来越依赖于数值预报产品的性能。预报产品检验是评价预报质量和提高预报水平的有效手段。针对2004年汛期（5～9月）中央气象台预报员及T213、HLAFS25、MM5、GRAPES、日本及德国等国内外数值预报模式短期时效的降水预报做了详细的统计学检验。检验结果表明，对于汛期平均而言，各模式与预报员的小雨预报较好，随降水量级的增加TS评分迅速下降，国内外数值预报模式之间降水预报水平差别不大，预报员与模式相比水平略高；但对于过程预报而言，过程不同，各模式和预报员的表现不同，预报员和MM5对河南暴雨预报较好；GRAPES和日本模式对台风暴雨预报略好；T213对于四川东部暴雨的大量级降水预报较好；无论是预报员，还是数值预报模式，北京暴雨的预报是一个典型的失败个例。同时，我们也发现检验系统存在一些问题，有待今后逐步改进。     

AN EFFECTIVE APPROACH TO SHORT-AND MEDIUM-RANGE PREDICTION OF TRACK AND INTENSITY OF TROPICAL CYCLONES

An objective prediction approach to the 6 h-144 h track and intensity of tropical cyclones over the northwestern Pacific is proposed. On the basis of both analog deviation technique and completed historical sample curve library, the track or intensity prediction for each forecast period are determined respectively through the optimum weighted superposition of displacement or intensity change of the cases, with different number and weighted coefficient corresponding to minimal analog deviation, from different tropical cyclone or different stage of the same cyclone. so that the prediction results for both forecast period and entire process are optimal. The verification suggests that the approach exhibits better forecast performance than other previous forecast methods by having remarkable decreasing forecast errors in short-and medium-range forecast of both track and intensity,and that the approach can also be used to predict effectively the decay process of tropical cyclone and is able to predict anomalous track and tropical depression.     

Skill of western North Pacific tropical cyclone intensity forecast guidance relative to Weighted-Analog technique

The accuracy of the western North Pacific tropical cyclone intensity forecast guidance products available at the Joint Typhoon Warning Center (JTWC) is evaluated relative to a new skill metric called Weighted Analog Intensity Pacific (WAIP) that includes knowledge of the JTWC official track forecast and the current intensity, which is information that is available at the time the intensity forecast is generated. An intensity consensus technique called S5XX that includes statistical-dynamic intensity forecasts plus other dynamic and thermodynamic prediction techniques has statistically significant smaller errors than WAIP at 24 h and 48 h and has similar accuracy through 120 h. While the track consensus CONW is a critical input to the JTWC official track forecast, it has no skill relative to WAIP as an intensity forecast. Three regional numerical models also have no skill relative to WAIP, and especially at forecast intervals beyond 72 h because their mean absolute errors are statistically significantly larger than for WAIP. Furthermore, these regional models have statistically significant positive or negative intensity biases relative to the verifying intensities. However, an experimental consensus technique called CMES that includes these three regional models has small accuracy relative to WAIP in the 24 h to 72 h forecast intervals. Geographical-based comparisons of the intensity guidance products with the WAIP indicate almost all of the products are more accurate than WAIP over the South China Sea region. The statistical-dynamic consensus technique S5XX does have skill through 72 h for landfalling situations along the coasts of China and Southeast Asia. At 120 h, the WAIP has superior performance over the guidance products over most areas of the western North Pacific, but again the S5XX is more accurate than WAIP for landfalling tropical cyclones on the Philippine Islands, Southeast Asia, South China, and northeastern Japan. This information will be useful to the forecaster in deciding when and where (or how much) to rely on each guidance product in preparing the five-day intensity forecast once the official track forecast has been established.     

基于多模式短期集合预报技术的热带气旋降水预报试验

利用中尺度AREM和WRF模式为试验模式,由对降水预报结果影响颇大的积云和边界层参数化方案构成的10个集合预报成员,开展有限区域多模式短期集合预报在热带气旋降水预报中的应用与研究.分别研究了单个模式集合预报和多模式集合预报在热带气旋"天鹅"(0907)降水预报中的应用.试验结果表明:(1) WRF模式集合预报效果整体上...     

用ECMWF数值预报产品作热带气旋路径预报的业务系统

以欧洲中心数值预报产品为基础,采用ＥＥＯＦＳ展开选取“典型场”作为数值预报产品的信息,以统计释用方法研究建立的,可以应用于南海区的热旋路径业务预报方法。该方法于１９９４年台汛期参加由广东省气象主持的“关于热带气旋预报业务试验项目”,进行了９个台风的共１４次预报试验,平均误差２４ｈ为１８７ｋｍ,４８ｈ为２５２ｋｍ。