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西北太平洋台风动力季节预报数值研究

Simulation of Seasonal Tropical Cyclone Activity over the Western North Pacific by Using the WRF Model

【作者】 宋天元

【导师】 王咏青;

【作者基本信息】 南京信息工程大学 , 气象学, 2012, 硕士

【摘要】 Camargo在世界气象组织会议报告中指出,进行热带气旋活动的统计和动力季节预报对预报员及公众来说意义重大。目前,在很多地区,热带气旋动力预报的多种方法都得到了发展。与此同时,西北太平洋热带气旋的路径和强度预报一直是实际预报工作的重点和难点。本文使用中尺度气象模式WRF (weather research and forecasting)对2004年、2006年和2010年的7月1日至9月30日,采用不间断模拟方法针对西北太平洋夏季台风进行了动力季节预报试验。模拟使用美国国家环境预报中心-国家大气研究中心(NCEP/NCAR)的FNL (Global Final Analysis)资料作为模拟计算的大尺度背景场,并用于计算实际大尺度要素场。热带气旋的实际路径使用日本气象厅(JMA)提供的最佳路径资料;热带气旋的模拟路径是利用Camargo提出的将涡度、气压、温度等多要素在不同层次相结合的台风定位标准,来确定模式中台风的中心位置。利用热带气旋各年整体频数、路径和强度来分析模拟效果;并利用GP指数、500hPa环境场、200hPa-850hPa水平风垂直切变和季风槽等要素场来分析模拟结果。模拟研究结果表明:1)在对3个月以内的台风作动力季节预报试验时,WRF模式模拟的热带气旋总个数与实况接近,模拟的登陆台风总数及登陆位置有一定的偏差。WRF模式在3个月的连续模拟中,对台风强度的模拟整体偏弱。2)要素场的诊断分析表明,WRF模式可以体现不同年份要素场的季节特征。从模拟月平均要素场与实际情况的对比中可以看到,模拟台风的生成和移动特点与实际接近。另一方面,随时间增长,模拟情况与实况的差别会增大。WRF模式具有一定的台风动力季节预报能力,但预报时限有待探讨。

【Abstract】 Camargo point out that statistical and dynamical seasonal tropical cyclone activity forecasts are proposed to be made available on a public Website for forecaster and other users at the WMO. Forecasts for different regions, using differing methodologies, have been developed up to present. Tracks and intensity of tropical cyclone are always different and importance for forecasting over the western North Pacific.By using the WRF (weather research and forecasting) model, the paper continuously simulated the seasonal tropical cyclone activity over western North Pacific from1July to30September2004,2006and2010. The relevant data what we used are FNL reanalysis data from the National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP/NCAR). The FNL data were utilized to estimate the large-scale environmental parameter and as the initial background fields for the meso-scale model simulation. The best track data from JMA were used as the objective tropical cyclone tracks data. And to make use of the850hPa relative vorticity, the sea level pressure, temperature in different levels, and so on, detect and track the model tropical storms. This method is advanced by Camargo in2002. We used the whole numbers, tracks and intensity of tropical cyclone to analysis the model outcome in different years. On the other hand, we utilize GP index,500hPa geopotential height,200hPa to850hPa vertical wind shear and so on, to analysis the simulative result.Results show that:1) the simulated total number of Typhoons is close to that from Best-track data set. The simulated landfall TC number has anomaly with real Typhoon number and it is the same for separate monthly landfall number. The simulated intensity of Typhoons is weaker than that from Best-track data set;2) Following the diagnostic analysis, the model shows better ability in reproducing Typhoon in different years. With comparison between the monthly average element fields by model data and by FNL data, we can see tropical cyclone have similar character in generate and move. But the ability tends to be weaker as the model time increases. This suggests that the model can be used to simulate the feature of seasonal tropical cyclone activity but the time limit needs further exploration.

【关键词】 WRF模式台风季节模拟
【Key words】 WRF modeltropical cycloneseasonal simulation
  • 【分类号】P444
  • 【下载频次】82
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