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1.
台风移动路径数值预报的影响因子初探   总被引:2,自引:0,他引:2  
本文对一个区域中α尺度数值预报业务模式进行垂直分层增加和积 云对流参数化改进,并设计八种对比试验方案,对9406号台风进行模拟预报,通过 对比分析各方案模拟预报的台风移动路径,探寻数值模式对台风移动路径预报的 影响因子。  相似文献   

2.
对流参数化方案的改进对GRAPES模式台风预报的影响研究   总被引:1,自引:0,他引:1  
将由NCEP改进之后的SAS(Simplified Arakawa-Shubert Scheme)对流参数化方案(NSAS方案)应用到GRAPES模式中,并对"启德"台风进行模拟,通过和原来SAS方案的预报结果进行比较,发现新方案对台风路径预报有显著改进。通过对NSAS方案中几个新增加的因素进行敏感性试验,发现其中对由于对流引发的扰动气压场如何影响动量输送这个问题的处理使得台风路径预报效果变差,采用动量的水平混合代替风场切变来对扰动气压场进行参数化以后,可有效改进该方案的预报效果。考虑动量的水平混合系数随高度变化可进一步改善预报结果。通过比较多个台风的预报结果发现,这种改进对台风路径预报的改进较稳定。  相似文献   

3.
陈锋  董美莹  冀春晓 《大气科学》2021,45(2):315-332
本文基于实况融合降水和雷达反射率因子,采用模糊逻辑法提出了一个新的对流云/层状云判别方法,进而改进了GSI(Gridpoint Statistical Interpolation)同化系统中的云分析方案(简称CUST方案)。以2019年6月19日影响浙江的一次梅雨过程为例,利用WRF(Weather and Forecast Research)模式与GSI同化系统开展了逐小时循环同化试验,分析了CUST方案对降水的模拟改进作用和可能影响过程,并与其他方案进行了对比,探讨了CUST方案的应用效果。结果表明:(1)新提出的CUST方案可较为准确地划分对流云和层状云,以此作为判别因子改进GSI同化系统中的云分析方案切实可行。(2)CUST方案在对流区域采用对流云分析方案,在非对流区域采用层云分析方案,减小了单纯对流云方案在非对流区域的空报现象、以及单纯层云方案在强对流区域的漏报现象,有效提升了短时降水的模拟能力。(3)CUST方案对模式起报初期(6 h甚至3 h内)的改进效果较为明显,且对小雨量级的改进幅度要大于大雨量级。(4)与基于地表感热和潜热通量确定的对流尺度速度作为对流判据的混合云分析方案(简称CSW方案)相比,CUST方案基于实况资料划分的对流云/层状云更为合理,模拟的降水结果占优,说明CUST方案方法有较好的应用前景。  相似文献   

4.
2013年国家气象中心对GRAPES_TYM进行了改进,包括集成GRAPES-Meso模式相关改进(即基础模式升级)、对流参数化过程由Simplified Arakawa-Schubert(简称SAS)升级为Meso-SAS,并对涡旋初始化方案进行优化。7个典型个例试验统计分析表明,基础模式升级可使72 h平均路径误差减小10%,在基础模式升级的基础上对流参数化方案的升级可使72 h平均路径误差减小20%,涡旋初始化方案的优化可使72 h平均路径误差进一步减小10%。基础模式的升级和对流参数化方案的升级对GRAPES_TYM的预报路径系统右偏有明显改进;基础模式升级对强度预报的影响不明显,Meso-SAS的应用对12~48 h强度预报的改善效果较显著,而台风初始化方案的优化可以减小6~24 h预报时段内的强度预报误差。2013年全年台风回算结果表明,升级后的GRAPES_TYM其48~72 h后的路径预报误差较准业务系统减小15%~20%,最大风速预报误差减小4%~16%。   相似文献   

5.
本文应用有限区域数值预报模式,并根据不同的积云参数化方案对1994年第6号台风登陆后低压的移动规律及其对应降水分布进行了数值模拟试验,结果表明积云对流参数化对于台风移动及其降水分布影响极大,是作出台风暴雨预报的关键过程。  相似文献   

6.
不同云降水方案对一次登陆台风的降水模拟   总被引:5,自引:8,他引:5  
利用美国最新发展的新一代中尺度数值预报模式(WRF),研究了不同云降水方案对一次登陆台风的降水模拟问题,结果表明,在网格距适当小的情况下,同时采用积云对流参数化方案和云微物理方案(Kessler方案)时,其降水预报优于只使用积云对流参数化方案时的预报;在台风降水模拟的初期,Kain-Fritsch方案比Betts-Miller方案产生降水更快,更接近实况降水;在台风登陆后随时间的延长,对流降水重要性逐步下降,网格尺度降水逐渐增强。  相似文献   

7.
基于WRF(Weather Research and Forecasting)模式及其3Dvar(3-Dimentional Variational)资料同化系统,采用36、12、4 km嵌套网格进行快速更新循环同化和不同的微物理及积云对流参数化方案对比试验,对2011年5月8日鲁中一次局地大暴雨过程进行了研究。结果表明,快速更新循环同化地面观测资料是影响模式降水落区预报准确性的关键因素,不同的微物理和积云对流参数化方案主要影响降水强度预报。采用不同的微物理参数化方案和积云对流参数化方案进行降水预报对比试验表明,LIN方案和WSM6(WRF Single-Moment 6-class)微物理参数化方案对降水预报均较好,LIN方案降水预报较WSM6方案略强。4 km网格预报使用K-F (Kain-Fritsch)积云对流参数化方案或不使用积云对流参数化方案,预报的降水均较好。4 km网格使用旧的K-F积云对流参数化方案,预报的近地层大气风场偏弱,导致大气动力抬升作用偏弱,从而造成模式降水预报偏弱。  相似文献   

8.
提出了建立一个旨在提高国家环境预报中心区域谱模式降水预报技巧的降水物理过程库。库中包括一个网格尺度的降水预报方案和一个具有显式耦合于边界层和对流性降水过程的对流触发函数的对流参数化方案。针对1995年5月15~17日期间一次全美国花园内的暴雨个例,在格距约25km的网格上进行了综合的敏感性试验。该文讨论了在对流参数化方案中建立的对流触发函数及其对预报降水的影响,重点阐述了对流参数化方案中的云属性与  相似文献   

9.
刘宇迪  翟子航 《气象科学》1999,19(4):335-342
Betts对流调整方案采用的是垂直温湿场向观测的准平衡热力结构松驰的方法。本文在一个考虑了台风初值化的移动套网格台风数值模式中,对Betts方案进行了初步试验。结果表明:Betts方案能较好的预报出台风移动的路径和降水过程,并在台风路径、降水落区预报以及对流增温的垂直分布等方面都略优于Kuo方案的预报结果。  相似文献   

10.
针对中国业务中期数值预报模式T213对中雨量级以上的降水预报空报比较明显的问题,文中对此模式预报的降水进行了诊断分析。发现T213模式预报的总降水分布主要是由可分辨尺度降水决定的,且在降水偏多最明显的地区,可分辨尺度的降水即超过或达到了观测的总降水,表明降水空报的主要原因在于可分辨尺度降水偏多。可分辨尺度降水偏多的可能原因有:土壤湿度初始化、云变量的初始化和直接产生降水的云与对流参数化方案存在一定的缺陷。鉴于前两者是目前国际上的难点,文中针对第3个方面的可能原因进行了分析和相应的改进。包括在对流方案之前增加一次云方案的调用;对流参数化方案的闭合由“动力型”改为对流有效位能调整闭合;更复杂的对流触发机制;改进冰沉降和降水通量计算。改进的主要目的是使对流参数化方案更活跃,从而减少格点尺度对流的发生。采用改进的方案,进行了敏感性试验和2005年夏季的连续滚动同化预报试验,并与中国区域400个标准站的降水观测和GPCP的全球降水观测进行了比较。结果表明,改进的方案无论是对中国区域还是全球夏季平均的降水分布预报都好于业务,但四川省和赤道东太平洋降水偏多的问题依然存在。中国区域的降水统计检验还表明,除小雨外,其他量级在大部分时效上降水的TS评分增加,预报偏差降低。  相似文献   

11.
将中国气象科学研究院(CAMS)混合双参数云微物理方案用于中尺度天气模式WRF,开展了对2013年超强台风天兔(1319)的模拟,通过与台风最佳路径、强度及热带降雨测量卫星(TRMM)资料对比,分析CAMS云微物理方案在模拟台风中的适用性及云微物理过程对模拟台风天兔的影响机制。设计了3组敏感性试验:修改雪粒子质量和落速系数(EXP1),采用海洋性云滴参数(EXP2),同时修改雪粒子质量和落速系数并采用海洋性云滴参数(EXP3)。结果表明:EXP1和EXP3由于霰碰并雪速率的增加及减小的雪下落通量,导致雪含量显著降低,同时也减少了整体冰相物的含量;EXP2和EXP3模拟的台风眼区对流有效位能快速减小,再现了前期台风的快速增强过程,路径偏差也最小;各试验模拟的小时降水率总体偏强,EXP3的降水空间分布与实况更接近,明显降低雪粒子含量,并一定程度上改善模拟的台风路径、强度及降水分布等。该结果不但可为改进适用于台风的云微物理参数化方案提供思路,也可加深云微物理过程对台风影响的认识。  相似文献   

12.
The impact of different cloud microphysics parameterization schemes on the intensity and structure of the Super-strong Typhoon Rammasun (1409) in 2014 is investigated using the Weather Research and Forecasting model version 3.4 with eight cloud microphysics parameterization schemes. Results indicate that the uncertainty of cloud microphysics schemes results in typhoon forecast uncertainties, which increase with forecast time. Typhoon forecast uncertainty primarily affects intensity predictions, with significant differences in predicted typhoon intensity using the various cloud microphysics schemes. Typhoon forecast uncertainty also affects the predicted typhoon structure. Greater typhoon intensity is accompanied by smaller vortex width, tighter vortex structure, stronger wind in the middle and lower troposphere, greater height of the strong wind region, smaller thickness of the eyewall and the outward extension of the eyewall, and a warmer warm core at upper levels of the eye. The differences among the various cloud microphysics schemes lead to the different amounts and distributions of water vapor and hydrometeors in clouds. Different hydrometeors have different vertical distributions. In the radial direction, the maxima for the various hydrometeors forecast by a single cloud microphysics scheme are collocated with each other and with the center of maximum precipitation. When the hydrometeor concentration is high and hydrometeors exist at lower altitudes, more precipitation often occurs. Both the vertical and horizontal winds are the strongest at the location of maximum precipitation. Results also indicate that typhoon intensities forecast by cloud microphysics schemes containing graupel processes are noticeably greater than those forecast by schemes without graupel processes. Among the eight cloud microphysics schemes investigated, typhoon intensity forecasts using the WRF Single-Moment 6-class and Thompson schemes are the most accurate.  相似文献   

13.
本文以GFS资料为初始场,利用WRF(v3.6.1)模式对2015年第22号台风“彩虹”进行了数值研究。采用CMA(中国气象局)台风最佳路径、MTSAT卫星、自动站降水为观测资料,对比了4个微物理方案(Lin、WSM6、GCE和Morrison)对“彩虹”台风路径、强度、结构、降水的模拟性能。模拟发现上述4个云微物理方案都能较好地模拟出“彩虹”台风西行登陆过程,但是其模拟的台风强度、结构及降水存在较大差异;就水成物而言,除GCE方案对雨水的模拟偏高以外,其他方案对云水、雨水过程的模拟较为接近,其差异主要存在于云冰、雪、霰粒子的模拟上。本文对比分析了WSM6和Morrison两个方案模拟的云微物理过程,发现WSM6方案模拟的雪和霰粒子融化过程显著强于Morrison方案,但是冰相粒子间转化过程的强度明显弱于Morrison方案。云微物理过程的热量收支分析表明:WSM6方案模拟的眼区潜热更强,暖心结构更为显著,台风中心气压更低。细致的云微物理转化分析表明,此次台风降水的主要云微物理过程是水汽凝结成云水和凝华为云冰;生成的云水一方面被雨水收集碰并直接转化为雨水,另一方面先被雪粒子碰并收集转化为霰,然后霰粒子融化成雨水;而生成的云冰则通过碰并增长转化为雪。小部分雪粒子通过碰并收集过冷水滴并淞附增长为霰粒子,随后融化为雨水,大部分雪粒子则直接融化形成地面降水。  相似文献   

14.
The basic structure and cloud features of Typhoon Nida (2016) are simulated using a new microphysics scheme (Liuma) within the Weather Research and Forecasting (WRF) model. Typhoon characteristics simulated with the Liuma microphysics scheme are compared with observations and those simulated with a commonly- used microphysics scheme (WSM6). Results show that using different microphysics schemes does not significantly alter the track of the typhoon but does significantly affect the intensity and the cloud structure of the typhoon. Results also show that the vertical distribution of cloud hydrometeors and the horizontal distribution of peripheral rainband are affected by the microphysics scheme. The mixing ratios of rain water and graupel correlate highly with the vertical velocity component and equivalent potential temperature at the typhoon eye-wall region. According to the simulation with WSM 6 scheme, it is likely that the very low typhoon central pressure results from the positive feedback between hydrometeors and typhoon intensity. As the ice-phase hydrometeors are mostly graupel in the Liuma microphysics scheme, further improvement in this aspect is required.  相似文献   

15.
This study examines the effects of cumulus parameterizations and microphysics schemes on the track forecast of typhoon Nabi using the Weather Research Forecast model. The study found that the effects of cumulus parameterizations on typhoon track forecast were comparatively strong and the typhoon track forecast of Kain-Fritsch (KF) was superior to that of Betts-Miller (BM). When KF was selected, the simulated results would be improved if microphysics schemes were selected than otherwise. The results from Ferrier, WSM6, and Lin were very close to those in the best track. KF performed well with the simulations of the western extension and eastern contraction changes of a North Pacific high as well as the distribution and strength of the typhoon wind field.  相似文献   

16.
With the Reisner-2 bulk microphysical parameterization of the fifth-generation Pennsylvania State University–U.S. National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5), this paper investigates the microphysical sensitivities of Typhoon Chanchu. Four different microphysical sensitivity experiments were designed with an objective to evaluate their respective impacts in modulating intensity forecasts and microphysics budgets of the typhoon. The set of sensitivity experiments were conducted ...  相似文献   

17.
Typhoon KROSA in 2007 is simulated using GRAPES, a mesoscale numerical model, in which a two-parameter mixed-phase microphysics scheme is implanted. A series of numerical experiments are designed to test the sensitivity of landfalling typhoon structure and precipitation to varying cloud microphysics and latent heat release. It is found that typhoon track is sensitive to different microphysical processes and latent heat release. The cloud structures of simulated cyclones can be quite different with that of varying microphysical processes. Graupel particles play an important role in the formation of local heavy rainfall and the maintenance of spiral rainbands. Analysis reveals that the feedback of latent heat to dynamic fields can significantly change the content and distribution of cloud hydrometeors, thus having an impact on surface precipitation.  相似文献   

18.
Based on a successful simulation of Typhoon Haikui (2012) using WRF (Weather Research & Forecasting) model with the WSM6 microphysics scheme, a high-resolution model output is presented and analyzed in this study. To understand the cause of the average gridded rainfall stability and increases after Haikui’s landfall, this research examines the fields of the physical terms as well as the vapor and condensate distributions and budgets, including their respective changes during the landing process. The environmental vapor supply following the typhoon landfall has no significant difference from that before the landfall. Although Haikui’s secondary circulation weakens, this circulation is not conducive to typhoon rainfall stability or increases, although the amounts of the six kinds of water substances (vapor, cloud water, cloud ice, snow, rain, and graupel) increase in the outer region of the typhoon. This reallocation of water substances is essential to the maintenance of rainfall. The six kinds of water substances are classified as vapor, clouds (cloud water and ice) and precipitation (snow, rain, and graupel) to diagnose their budgets. This sorting reveals that the changes in the budgets of different kinds of water substances, caused by the reduced mixing ratios of snow and ice, the water consumption of clouds, and the transformation of graupel, induce increased concentrations of precipitation fallout, which occur closer to the ground after typhoon landfall. In addition, this pattern is an efficient way for Haikui’s rainfall to remain stable after its landfall. Thus, the allocation and budget analyses of water substances are meaningful when forecasting the typhoon rainfall stability and increases after landfall.  相似文献   

19.
Direct assimilation of cloud-affected microwave brightness temperatures from AMSU-A into the GSI three-dimensional variational(3D-Var) assimilation system is preliminarily studied in this paper. A combination of cloud microphysics parameters retrieved by the 1D-Var algorithm(including vertical profiles of cloud liquid water content, ice water content, and rain water content) and atmospheric state parameters from objective analysis fields of an NWP model are used as background fields. Three cloud microphysics parameters(cloud liquid water content, ice water content, and rain water content) are applied to the control variable. Typhoon Halong(2014) is selected as an example. The results show that direct assimilation of cloud-affected AMSU-A observations can effectively adjust the structure of large-scale temperature, humidity and wind analysis fields due to the assimilation of more AMSU-A observations in typhoon cloudy areas, especially typhoon spiral cloud belts. These adjustments, with temperatures increasing and humidities decreasing in the movement direction of the typhoon,bring the forecasted typhoon moving direction closer to its real path. The assimilation of cloud-affected satellite microwave brightness temperatures can provide better analysis fields that are more similar to the actual situation. Furthermore, typhoon prediction accuracy is improved using these assimilation analysis fields as the initial forecast fields in NWP models.  相似文献   

20.
李新峰  赵坤  王明筠  明杰 《气象科学》2013,33(3):255-263
高分辨率的中尺度预报模式ARPS及其3DVAR/云分析系统,针对2010年登陆福建的超强台风“鲇鱼”,研究对流可分辨尺度下,每1h循环同化沿海新一代多普勒雷达网资料分析、研究对台风初始场和预报场的改进作用.结果表明:单独同化雷达资料可显著改善初始场中的台风内核区动力和热力结构,以及台风强度和位置,进而提高18h台风强度、路径和降水预报,但预报路径和降水分布与实况仍存在差异.在雷达资料同化基础上加入常规观测资料,对初始场中台风内核区结构改进不大.但在显著调整大尺度背景场,从而进一步减少台风路径预报误差,能准确预报出福建沿海两个强降水区域的位置和强度.总体而言,雷达资料同化主要提高台风结构分析,而常规观测资料同化主要改善环境场分析,两者有效结合使得预报结果和实况最为接近.  相似文献   

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