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能量频散对台风结构和移动的作用 总被引：10，自引：10，他引：10
本文用双Ｆｏｕｒｉｅｒ展开的解析方法和β平面准地转正压模式数值试验的方法，研究了台风涡旋能量频散及其对台风路径的影响问题。解析与数值试验的结果一致地表明，由于能量频散，在台风中心以东方向形成了一个低－高－低值系统的波列。三组数值试验的结果表明，波列中的高值系统对台风的结构和移行具有明显的影响。 相似文献
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In the context of a model of tropical cyclone intensity based on an improved meso-scale atmospheric model, numerical simulation is performed of the track and intensity variation of tropical cyclones(TC) arising from sea surface temperature(SST) variation over a specified sea region. Evidence suggests that the model is capable of modeling quite welt the track and intensity of TC:SST variation leads to an abrupt change in the cyclone intensity:the response of the cyclone to the abrupt SST change lasts 8-12 h. 相似文献
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A SIMULATION STUDY OF THE INFLUENCE OF LAND FRICTION ON LANDFALL TROPICAL CYCLONE TRACK AND INTENSITY 总被引：1，自引：0，他引：1
A quasi-geostrophic barotropic vorticity equation model is used to simulate the influences of topographic forcing and land friction on landfall tropical cyclone track and intensity. The simulation results show that tropical cyclone track may have sudden deflection when the action of topographic friction dissipation is considered, and sudden deflection of the track is easy to happen and sudden change of tropical cyclone intensity is not clear when the intensity of tropical cyclone is weak and the land friction is strong.The land friction may be an important factor that causes sudden deflection of tropical cyclone track around landfall. 相似文献
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不同尺度涡旋相互作用对台风的结构和移动的影响 总被引：7，自引：3，他引：7
根据大气运动原始方程组导出一个支配台风中心移动的基本方程，方程中包括了非绝热加热，温度场分布，地形与摩擦等各中能影响台风移动的强迫因子。对非绝热加热与水平温度分布的使用所作分析表明，非轴对称的非绝热引导作用可使台风加速、减速或转向运动；温度场上的准区对台风有吸收作用。 相似文献
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Russell L. Elsberry 《Asia-Pacific Journal of Atmospheric Sciences》2010,46(2):217-220
Tropical cyclone track forecasts have been improved, and forecast intervals have been extended to five days, owing to improved global and regional numerical model guidance. Critical time requirements that must be met for operational use of the deterministic model track forecasts are summarized for the U.S. and other selected non-U.S. tropical cyclone warning centers. One of the most accurate deterministic model forecasts from the European Center for Medium-range Weather Forecasts arrives too late to be used with other models at the + 6 h warning time, and thus is at least 12 h old before it can be operationally used. The time-critical nature of the tropical cyclone warning system is a major obstacle to operational use of single-model, or proposed multi-model, ensemble prediction system (EPS) mean and spread information, which is 12 h (or 18 h) delayed. This EPS mean and spread must also be superior to the mean and spread of the consensus of deterministic models that are available six hours earlier. These requirements must be met before the EPS tropical cyclone tracks will be operationally useful in specifying the uncertainty in the official track forecasts, which is the next challenge in tropical cyclone track warnings. 相似文献
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THE STRUCTURE OF TROPICAL CYCLONE BY TOVS AND ITS APPLICATION IN NUMERICAL WEATHER PREDICTION 总被引：1，自引：2，他引：1
The TOVS data are used to study the structure of a number of tropical cyclones for the year 2000.
Differences are found to some extent between what is found and classic conceptual models in that (1) the
horizontal structure is asymmetric and variable so that the low-value centers at low levels of the geopotential
height field (or the high-value centers at high levels) do not necessarily coincide with the high-value centers of
the temperature field; (2) the vertical structure is also variable in the allocation of the anomalies of the
geopotential height field between low values at low levels and high values at high levels. It is especially noted
that the centers of the anomalies are tilting at both high and low levels or the high level is only at the edge of a high-pressure zone. There is not any significant high-value anomalous center in a corresponding location with the
tropical cyclone. The structure of tropical cyclone in the TOVS is also used as reference to modify the structure of typhoon BOGUS in the numerical prediction model system of tropical cyclones. It is found that the modified BOGUS
performs better in coordinating with the environment and predicting the track of the tropical cyclone. The
demonstration is two-fold — the structure of the typhoon BOGUS is such that it means much in the track
prediction and the use of the TOVS-based tropical cyclone structure really helps in improving it. It provides the
foundation for modification and evolution of typhoon BOGUS. 相似文献
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Tropical cyclone track and intensity prediction: The generation and assimilation of high-density, satellite-derived data 总被引：1，自引：0，他引：1
J. F. Le Marshall L. M. Leslie R. F. Abbey Jr. L. Qi 《Meteorology and Atmospheric Physics》2002,80(1-4):43-57
Summary The impact of recent scientific and technological advances in tropical cyclone track, intensity and structure modeling is
discussed. Since the early 1990s, developments have occurred in remote sensing, data assimilation procedures, numerical models
and high performance computing. In particular, there is now quasi-continuous high spatial and temporal resolution data coverage
over the previously data-sparse oceans where tropical cyclones spend most of their life cycles. There has been a rapid development
of data assimilation methodologies capable of using these data to initialize high-resolution prediction models. Model developments
have reached a stage of maturity where the representation of many of the physical processes necessary for improved tropical
cyclone track and intensity prediction are now included. Finally, available computer power has reached the teraflop range.
Most operational centers have high performance computers capable of tropical cyclone modeling at resolutions necessary for
skillful track and intensity simulations.
This article focuses on combining all of the above developments in a tropical cyclone data analysis and prediction system.
The system has produced statistically significant reductions in the mean forecast error statistics for tropical cyclone track
predictions and resulted in far more realistic simulations of tropical cyclone intensity and structure. A large number of
tropical cyclones have been modeled, with emphasis on those classified as being “difficult” storms to predict accurately.
These difficult storms are most responsible for rapidly growing forecast errors. Our results are illustrated by case studies
of such tropical cyclones.
Received October 9, 2001 Revised December 28, 2001 相似文献
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基于副热带奇异向量的初值扰动方法已应用于GRAPES （Global and Regional Assimilation PrEdiction System）全球集合预报系统,但存在热带气旋预报路径离散度不足的问题。通过分析发现,热带气旋附近区域初值扰动结构不合理导致预报集合不能较好地估计热带气旋预报的不确定性,是路径集合离散度不足的可能原因之一。通过建立热带气旋奇异向量求解方案,将热带气旋奇异向量和副热带奇异向量共同线性组合生成初值扰动,以弥补热带气旋区域初值扰动结构不合理这一缺陷,进而改进热带气旋集合预报效果。利用GRAPES全球奇异向量计算方案,以台风中心10个经纬度区域为目标区构建热带气旋奇异向量求解方案,针对台风“榕树”个例进行集合预报试验,并开展批量试验,利用中国中央气象台最优台风路径和中国国家气象信息中心的降水观测资料进行检验,对比分析热带气旋奇异向量结构特征和初值扰动特征,评估热带气旋奇异向量对热带气旋路径集合预报和中国区域24 h累计降水概率预报技巧的影响。结果表明,热带气旋奇异向量具有局地化特征,使用热带气旋奇异向量之后,热带气旋路径离散度增加,路径集合平均预报误差和离散度的关系得到改善,路径集合平均预报误差有所减小,集合成员更好地描述了热带气旋路径的预报不确定性;中国台风降水的小雨、中雨、大雨、暴雨各量级24 h累计降水概率预报技巧均有一定提高。总之,当在初值扰动的生成中考虑热带气旋奇异向量后,可改进热带气旋初值扰动结果,并有助于改善热带气旋路径集合预报效果。 相似文献
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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. 相似文献
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统计及数值模式客观预报已作为当今发布要素预报的重要参考依据,而制作客观预报的基础是初始资料及初始场的分析。气象场的客观分析方法有很多种,主要的有多项式插值法、遂次订正法、变分技术法、特征函数展开法,和统计插值法等。对于客观分析结果的一些特征近年来曾有过不少的研究。例如,对于美国国家气象中心的Hough函数业务客观分析(特征函数展开法的一种)的研究发 相似文献
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A tropical cyclone is a kind of violent weather system that takes place in warmer tropical oceans
and spins rapidly around its center and at the same time moves along surrounding flows. It is generally
recognized that the large-scale circulation plays a major role in determining the movement of tropical
cyclones and the effects of steering flows are the highest priority in the forecasting of tropical cyclone
motion and track. This article adopts a new method to derive the steering flow and select a typical
swerving track case (typhoon Dan, coded 9914) to illustrate the validity of the method. The general
approach is to modify the vorticity, geostropical vorticity and divergence, investigate the change in the
non-divergent stream function, geoptential and velocity potential, respectively, and compute a modified
velocity field to determine the steering flow. Unlike other methods in regular use such as weighted average
of wind fields or geopoential height, this method has the least adverse effects on the environmental field
and could derive a proper steering flow which fits well with storm motion. Combined with other internal
and external forcings, this method could have wide application in the prediction of tropical cyclone track. 相似文献
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J. Le Marshall 《Meteorology and Atmospheric Physics》1998,65(3-4):141-151
Summary Tropical cyclone track prediction remains a vexing problem in meteorology, particularly for numerical weather prediction. While there has been significant improvement in forecast skill in recent years, errors in prognosis, particularly for recurving cyclones still remain unacceptably high. Consistent with track prediction being to a significant extent an initial value problem, there has been, in recent years, cogent evidence that, a combination of high resolution numerical modelling, the use of appropriate assimilation techniques and the exploitation of high spatial and temporal resolution observations can improve the accuracy of tropical cyclone forecasts.Before landfall, tropical cyclones have their genesis and move over the data-sparse tropical oceans. Here the prediction of their movement is an application for which remotely sensed data are quintessential. In this context, this paper examines the increasingly important contribution of cloud and water vapour motion vectors to tropical cyclone prediction and evaluates their import to accurate prediction in terms of both the numerical modelling characteristics and the data assimilation techniques employed.Overall, it is shown that cloud and water vapour drift winds have made a significant contribution to the tropical cyclone track forecasting problem when used with conventional intermittent assimilation techniques, such as 6-hourly cycling, and, more recently, with continuous assimilation techniques such as 3- and 4-dimensional variational assimilation. These continuous assimilation schemes appear to have the potential to use near continuous asynoptic wind data in the most effective way.With 3 Figures 相似文献
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R. L. Elsberry 《Meteorology and Atmospheric Physics》1995,56(1-2):81-99
Summary Considerable advancements have recently been made in understanding tropical cyclone motion. Based on these new understandings, the requirements for accurate tropical cyclone motion prediction with dynamical models can be specified. Four issues related to dynamical track prediction are the initial specifications of the environmental wind field, the symmetric vortex and the asymmetric vortex structure, as well as the adequacy of the models to predict the time evolution of each of these three components of the total wind field. Recently developed barotropic and limited-region or global baroclinic models are examined in terms of these issues. The capability of the Hurricane Research Division barotropic model to provide skillful track forecasts to 48 h retrospectively substantiates that tropical cyclones motion is governed by barotropic dynamics to first order. Limited-region baroclinic models are demonstrated to have many of the numerical characteristics, physical process representations, and initial condition specifications that will be required to properly predict tropical cyclone tracks. In particular, the semioperational Geophysical Fluid Dynamics Laboratory model most closely addresses all of the above issues, and has demonstrated potential for markedly improved tracks for a small sample of cases. Finally, the inclusion of some aspects of tropical cyclone structure in the initial conditions of global baroclinic models has improved their track predictions. Thus, the outlook is for a significant improvement in dynamical track predictions.With 6 Figures 相似文献
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大地形上空偶极子东移对热带气旋路径的影响 总被引：1，自引：0，他引：1
With a quasi-geostrophic barotropic model on the β-plane with a topography term, 16 experiments were performed with an integration period of 6 days. The interaction between tropical cyclone tracks and 500 kin-scale vortices originating from the western part ora large-scale topography is investigated. It is suggested that this kind of interaction may have a significant impact on the moving speed and direction of tropical cyclones. Under certain conditions, this interaction may be a factor in causing an abnormal tropical cyclone track. Furthermore, the effect of large-scale topography plays an important role in the formation of unusual tropical cyclone tracks. 相似文献
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L. M. Leslie R. F. Abbey Jr. G. J. Holland 《Meteorology and Atmospheric Physics》1998,65(3-4):223-231
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 相似文献