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1.
人造台风模型中三维风场的改进及敏感性模拟研究 总被引：1，自引：1，他引：0
对MM5的人造台风风场方案进行了分析,并引入台风移速、移向、摩擦等客观因素构造非对称切向风场,尝试选择合理的径向风方案,并考虑风场垂直结构,改进出三维非对称台风风场模型.通过对"云娜"台风模式初始场的对比发现,径向风及高空反气旋环流的引入突出了台风的基本特征,与观测事实相接近.最后进行敏感性数值模拟,通过比较台风路径及移速、海平面气压、最大风速等模拟要素,结果表明:改进后的台风模型通过订正初始场,对台风路径及强度预报效果的提高也有正效应. 相似文献
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非对称台风风场的动力初始化应用研究 总被引：2，自引：2，他引：0
在对比NCAR-AFWA三维Bogus(虚拟)风场及风压场方案的基础上,虚拟台风模型中的水平风场采用考虑台风移速、移向、摩擦等客观因素的非对称方案,垂直风场采用考虑高空反气旋环流的风廓线方案,然后利用Nudging动力初始化技术形成新的模式初始场.最后对"云娜"台风进行数值模拟,结果表明:通过合理引入客观因子及观测事实对台风Bogus模型进行构建,并利用同化方法使各个物理量相互协调,可以使初始场与实况更加接近,从而在一定程度上提高台风路径及强度的预报水平,并对降水分布的预报效果也有所改善. 相似文献
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There is distinct difference in the tangential wind profile between different typhoons in the western North Pacific. At present, only two parameters, maximum wind and radius of maximum wind, are used in NCAR-AFWA bogus for MM5 mesoscale numerical model. As a result, sometimes the outer structure of typhoon cannot be described accurately. The tangential wind profile of NCAR-AFWA bogus is improved by introducing radii of 25.7 m/s and 15.4 m/s, and then the track and intensity of Typhoon Nockten (No.0425) are simulated. The results show that the simulations of track and intensity of typhoon both have been improved by simultaneously introducing the radii in the tangential wind profile of typhoon bogus. At the same time, there is improvement in the gale wind range of the typhoon simulated. 相似文献
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2011年“洛克”和“桑卡”双台风预报效果的初值试验研究 总被引：1，自引：3，他引：1
采用南海台风模式,对2011年业务预报误差较大的台风“洛克”（1115）和“桑卡”（1116）双台风的初值方案进行试验和研究,目的在于寻求改进预报的线索,从而提升台风模式性能。针对“洛克”和“桑卡”台风设计了几组初值方案对比试验,结果表明,仅对弱台风“桑卡”进行重定位和bogus的初值处理,与对双台风都进行初值处理相比较,两台风的路径预报误差减小。分析认为仅对弱台风作初值处理以改善其涡旋环流的影响是该双台风路径预报得以改进的原因。对2011—2012年所有弱台风进行批量预报试验,结果表明对弱台风采用重定位和bogus的初值处理,台风路径预报和强度预报的误差减小。对弱台风进行重定位和bogus初值处理,可改善模式对弱台风的预报效果。此外,目前南海台风模式中现有的bogus方法构造的涡旋相对于弱台风而言云顶偏高,可考虑发展针对弱台风的涡旋模型。 相似文献
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适应性非对称人造台风方案对热带气旋路径的模拟预报 总被引：1，自引：1，他引：1
设计了一种新的适应性非对称人造台风方案。该方案中，初始场中植入的非对称人造台风不但与初始场之间更为协调，而且还包括较多的非对称信息。应用此方案对两个台风个例的路径进行了数值模拟试验，模拟结果与实况较为接近。 相似文献
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国家气象中心台风路径数值预报模式自1996年6月投入业务运行以来, 一直在背景场中采用经验平滑滤波技术消除浅台风和嵌入轴对称的台风bogus涡旋技术。但事实上, 在采用经验平滑技术消除背景场中弱的位置不准确的浅台风涡旋同时, 也滤除了台风中心周围一些宝贵的非对称气流结构, 同时, 由于实际的台风涡旋结构是非对称的, 因而对采用轴对称涡旋的模式初始场而言, 或多或少的贡献了一些模式预报结果的路径误差。为了调查这部分非对称结构对台风预报路径误差的影响, 从T213L31全球谱模式提供的背景场中抽取浅台风周围的非对称流场, 将之加入到轴对称的台风bogus涡旋中。初步的个例试验发现, 加入非对称流场后, 能有效地减少台风路径预报误差。 相似文献
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EXPERIMENTAL STUDY ON A DYNAMIC ASYMMETRICAL TYPHOON INITIALIZATION SCHEME BASED ON 4D-VAR 总被引：1，自引：1，他引：0
Axisymmetric bogus vortexes at sea level are usually used in the traditional bogus data
assimilation (BDA) scheme. In the traditional scheme, the vortex could not accurately describe the specific
characteristics of a typhoon, and the evolving real typhoon is forced to unreasonably adapt to this
changeless vortex. For this reason, an asymmetrical typhoon bogus method with information blended from
the analysis and the observation is put forward in this paper, in which the impact of the Subtropical High is
also taken into consideration. With the fifth-generation Penn State/NCAR Mesoscale Model (MM5) and its
adjoint model, a four-dimensional variational data assimilation (4D-Var) technique is employed to build a
dynamic asymmetrical BDA scheme to assimilate different asymmetrical bogus vortexes at different time.
The track and intensity of six summer typhoons much influenced by the Subtropical High are simulated
and the results are compared. It is shown that the improvement in track simulation in the new scheme is
more significant than that in the traditional scheme. Moreover, the periods for which the track cannot be
simulated well by the traditional scheme can be improved with the new scheme. The results also reveal
that although the simulated typhoon intensity in the new scheme is generally weaker than that in the
traditional scheme, this trend enables the new scheme to simulate, in the later period, closer-to-observation
intensity than the traditional scheme. However, despite the fact that the observed intensity has been largely
weakened, the simulated intensity at later periods of the BDA schemes is still very intensive, resulting in
overly development of the typhoon during the simulation. The limitation to the simulation effect of the
BDA scheme due to this condition needs to be further studied. 相似文献
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Numerical Study on the Impacts of the Bogus Data Assimilation and Sea Spray Parameterization on Typhoon Ducts 总被引：1，自引：0，他引：1 
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下载免费PDF全文 FEI Jianfang DING Juli HUANG Xiaogang CHENG Xiaoping HU Xiaohua 《Acta Meteorologica Sinica》2013,27(3):308-321
The Weather Research and Forecasting model version 3.2 (WRF v3.2) was used with the bogus data assimilation (BDA) scheme and sea spray parameterization (SSP), and experiments were conducted to assess the impacts of the BDA and SSP on prediction of the typhoon ducting process induced by Typhoon Mindule (2004). The global positioning system (GPS) dropsonde observations were used for comparison. The results show that typhoon ducts are likely to form in every direction around the typhoon center, with the main type of ducts being elevated duct. With the BDA scheme included in the model initialization, the model has a better performance in predicting the existence, distribution, and strength of typhoon ducts. This improvement is attributed to the positive effect of the BDA scheme on the typhoon’s ambient boundary layer structure. Sea spray affects typhoon ducts mainly by changing the latent heat (LH) flux at the air-sea interface beyond 270 km from the typhoon center. The strength of the typhoon duct is enhanced when the boundary layer under this duct is cooled and moistened by the sea spray; otherwise, the typhoon duct is weakened. The sea spray induced changes in the air-sea sensible heat (SH) flux and LH flux are concentrated in the maximum wind speed area near the typhoon center, and the changes are significantly weakened with the increase of the radial range. 相似文献
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Experiments for short range forecasting of typhoon tracks over the South China Sea Region were carried out using limited-area numerical model recently developed by the authors.Due to the shortage of sounding data over the sea, typhoon circulations are usually obtained incompletely from objective analysis, or with significant deviation of the centre from reality.Therefore a set of schemes for typhoon initialization are proposed here to construct a bogus typhoon with the circulation being consistent with the physical processes included in the limited-area model.Based on the schemes bogus data over the model grids are created and analysed together with conventional observational data.Then the normal model initialization scheme is issued to further modulate the model typhoon with the numeriCal modeel.Some experiments of sensitivity in various aspects are conducted for further improvement of typhoon track predictions.The experimental results for a number of typhoon landing in southern China in 1993 and 1994 shows that the limited-area model is capable of predicting typhoon tracks in the southern China region. 相似文献
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在台风业务系统中使用卫星云导风资料的试验 总被引：1，自引：0，他引：1
在国家气象中心台隐数值预报业务系统中引入国家卫星气象中心提供的卫星云导风资料,进行两项预报试验。第一项是把卫星云导风资料作为观测资料进行最优插值客观分析;第二项是将云导风资料加入到轴对称的人造台风模型风场上,使之产生非对称风场。试验结果表明：卫星云导风资料作为观测资料进入模式后对减小台风路径预报误差效果明显;用云导风形成人造台风模型非对称风场可进一步提高台风路径预报精度。 相似文献
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台风数值模拟中bogus涡旋四维变分同化的研究 总被引：9，自引：1，他引：8
研究用MM5四维变分同化系统同化bogus涡旋变量对台风数值模拟的影响,对2002年13号台风Phanfone进行48h预报,结果表明：用四维变分方法同化bogus涡旋变量效果优于在背景场中直接植入模型涡旋的传统bogus技术。同时同化bogus涡旋的风、气压、温度和比湿效果不如只同化气压和其中任一变量。同化bogus涡旋的气压和比湿,能够调整模式初始场的其他变量,得到结构更清晰、与环境场更协调的初始涡旋,从而在一定程度上提高了台风Phanfone路径和强度预报的准确性。 相似文献
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A typhoon bogus data assimilation scheme (BDA) using dimension-reduced projection four-dimen-sional variational data assimilation (DRP-4-DVar),called DRP-BDA for short,is built in the Advanced Regional Eta Model (AREM).As an adjoint-free approach,DRP-BDA saves time,and only several minutes are taken for the full BDA process.To evaluate its performance,the DRP-BDA is applied to a case study on a landfall ty-phoon,Fengshen (2008),from the Northwestern Pacific Ocean to Guangdong province,in which the bogus sea level pressure (SLP) is assimilated as a kind of observa-tion.The results show that a more realistic typhoon with correct center position,stronger warm core vortex,and more reasonable wind fields is reproduced in the analyzed initial condition through the new approach.Compared with the control run (CTRL) initialized with NCEP Final (FNL) Global Tropospheric Analyses,the DRP-BDA leads to an evidently positive impact on typhoon track forecasting and a small positive impact on typhoon inten-sity forecasting.Furthermore,the forecast landfall time conforms to the observed landfall time,and the forecast track error at the 36th hour is 32 km,which is much less than that of the CTRL (450 km). 相似文献
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In this study,the authors introduce a new bogus data assimilation method based on the dimension-reduced projection 4-DVar,which can resolve the cost function directly in low-dimensional space.The authors also try a new method to improve the quality of samples,which are the base of dimension-reduced space projection bogus data assimilation (DRP-BDA).By running a number of numerical weather models with different model parameterization combinations on the typhoon Sinlaku,the authors obtained two groups of samples with different spreads and similarities.After DRP-BDA,the results show that,compared with the control runs,the simulated typhoon center pressure can be deepened by more than 20 hPa to 30 hPa and that the intensity can last as long as 60 hours.The mean track error is improved after DRP-BDA,and the structure of the typhoon is also improved.The wind near the typhoon center is enhanced dramatically,while the warm core is moderate. 相似文献
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采用预报涡旋的初始化方案对2015年台风“莲花”、“灿鸿”的试验研究 总被引：2，自引：1，他引：2
提出了一种采用预报涡旋的初始化方案,用预报涡旋代替bogus模型参与构建模式初始场,采用权重形式合成预报涡旋和分析涡旋获取台风初始涡旋。针对2015年“莲花”和“灿鸿”台风,基于该初始化方案设计了一系列对比试验进行数值模拟,并对结果进行分析。结果表明:(1)该方案得到的台风初始涡旋结构比bogus模型合理;(2)预报涡旋权重不宜取太大;(3)从长时效预报效果看,采用24 h内预报涡旋比采用长时效预报涡旋台风的路径和强度误差减小;(4)采用同一权重方案对“莲花”、“灿鸿”预报的改进效果不同,其原因与预报涡旋和分析涡旋的协调程度有关。多台风情形下可在初步评估的基础上采用不同时效的预报涡旋和不同权重方案。 相似文献
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The MM5, which is the PSU/NCAR mesoscale nonhydrostatic limited-area model, and its
adjoining modeling system are used in this paper. Taking T106 analysis data as background field the authors
generate an optimal initial condition of a typhoon by using two bogus data assimilation schemes, and conduct
some numerical simulating experiments. The results of No.9608 typhoon (Gloria) show that the optimal initial
field have some dramatic improvements, such as inaccurate position of typhoon center, weaker typhoon
circulation and incomplete inner structure of the typhoon, which are caused by shortage of data over the sea.
Some improvements have been made in the track forecast. Through several comparing experiments, the
initialization optimized by BDA scheme is found to be more reasonable than GFDL scheme and its typhoon track
forecast is better. 相似文献
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基于BDA扰动法的台风路径集合预报试验研究 总被引：7，自引：7，他引：7
提出一种新的方法（BDA扰动方法）对台风路径进行集合预报。BDA扰动方法是基于BDA同化方案。通过扰动台风的中心位置和台风强度得到一系列模型台风，将之分别同化到同一环境场中得到一系列扰动初始场，从而对台风进行集合预报的方法。本文选取四个台风个例进行数值试验，将直接用BDA方案同化初始场的模拟结果与采用BDA扰动方法模拟的结果进行比较，发现：利用BDA扰动方法对台风路径进行集合预报能进一步提高路径预报精度；同时发现：对于BDA扰动方法，若与初始定位扰动相结合，5hPa的台风强度扰动幅度可能比10hPa的更适宜。 相似文献
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应用ATOVS资料和非对称Bogus资料对登陆台风韦帕的4DVAR数值模拟分析 总被引：3，自引：1，他引：2
前人研究中BDA方法采用的轴对称Bogus台风不能反映个别台风具体特征并弃掉了背景场的合理成分,也没有考虑大环境场的影响及湿热要素的同化。因此,提出一种充分融合分析场信息和实际观测信息并考虑副高影响的精细非对称台风Bogus方法,并在MM5的伴随同化系统中引入快速辐射传输模式RTTOV8,通过四维变分同化(4DVAR)技术,加入海面风场和气压场Bogus资料及多颗卫星多条轨道上的ATOVS红外和微波卫星辐射亮温资料并考虑Noah陆面过程方案来对登陆台风韦帕进行数值模拟,结果表明,单独同化海面Bogus资料的BDA方案可间接产生初始场非对称三维环流结构和暖心结构,但对湿度场及台风周围大环境场的调整不足,台风登陆后的路径预报改善也不明显;引入陆面过程方案弥补了Bogus资料对台风登陆后路径预报的不足;加入ATOVS资料能对湿度场及台风周围环境场做出调整,重构了大量中尺度结构信息,取得更为精细的初始台风环流和温压湿场结构,保持BDA方案路径及强度预报的优势的同时,使预报的降水强度增加,降水落区发生改变。 相似文献