黄伟,梁旭东. 2010. 台风涡旋循环初始化方法及其在GRAPES-TCM中的应用[J]. 气象学报, 68(3):365-375, doi:10.11676/qxxb2010.036
台风涡旋循环初始化方法及其在GRAPES-TCM中的应用
A cycling typhoon like vortex initialization scheme and itsapplication to GRAPES-TCM.
投稿时间:2009-02-02  修订日期:2009-08-03
DOI:10.11676/qxxb2010.036
中文关键词:  循环初始化, 热带气旋, GRAPES-TCM
英文关键词:Cycling initialization, TC, GRAPES-TCM
基金项目:国家重点基础研究发展计划(2009CB421500),国家自然科学基金重点项目(0815028)和国家科技支撑计划课题“灾害天气精细数值预报系统及短期气候集合预测研究”。
作者单位
黄伟 中国气象局上海台风研究所上海200030 
梁旭东 中国气象局上海台风研究所上海200030 
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中文摘要:
      由于观测资料的缺乏,全球数值模式中台风涡旋一般较弱。但在区域数值模式中由于能使用更高的分辨率,采用适合台风的物理过程计算方案,因此区域模式中的台风涡旋能得到更好的发展。通常情况下,由于区域模式每次预报都使用全球模式的预报结果作为背景场,因此在区域模式中得到发展的台风涡旋并不能出现在下一次预报的初始场中。本研究结合BDA和涡旋重定位方法,采用MC-3DVar技术将台风涡旋初始化与资料同化技术结合起来,提出了循环初始化技术。在该技术中,提取区域模式6 h预报的台风涡旋周围的廓线资料,并根据台风观测位置将这些廓线资料平移到正确位置进行同化,从而使得台风涡旋在区域模式中得到循环发展。个例试验的结果表明循环初始化方案能更准确地刻画初始台风的强度和结构,相比控制试验,其初始台风强度更接近实况,结构更为合理,而且与观测更为接近,相应的,台风路径和强度预报也有很大的改善。对超强台风“蔷薇”的22次预报的总体结果表明,相对控制试验,循环初始化方案使得试验的总体路径预报距离误差从24 h的113 km降低到89 km,从48 h的188 km降低到184 km。另一方面,循环初始化方案对强度预报也有很大改善,24 h中心气压均方根误差从控制试验的32 hPa降到22 hPa。2009年汛期开始,以循环初始化方案为基础的GRAPES-TCM投入准业务试验,在对2009年2、3、4和6号热带气旋的准业务运行的预报结果的分析表明,新的方案较之采用涡旋重定位的GRAPESTCM业务系统在路径和强度预报能力方面均有较大改善。
英文摘要:
      Due to limited observational data, the vortex fields in a global numeric al model are often too weak. However, in a regional model, the TC vortex fields are well developed because it has a higher resolution and more sophisticated physical process package which benefit typhoon simulation. Generally, the background fields for the regional model are from the global model forecasts. The well developed TC vortex in a regional model is unable to be inherited so as to occur in the initial field for the next forecast of the regional model. In this paper, the BOGUS data assimilation (BDA) scheme and the TC vortex relocation scheme are combined, and using MC-3DVAR technique, a new vortex initialization scheme called cycling data assimilation (CDA) scheme is developed. In this scheme, the profiles around the TC center are extracted from the previous 6-h ours forecast fields of a regional model. Then these profile data are displaced to an accurate location determined based on the TC location from the observations and assimilated into the first guest fields which are from the global analyses. The CDA scheme insures that the TC vortex developed in the regional model will be kept in the next run. Case study shows that the CDA scheme has a positive impact on the initial TC intensity and structure. Compared to that of the control experiment, the intensity of the initial TC is closer to the observations with the structure more compact. Therefore, the experiment using the CDA scheme has a better performance on the track and intensity forecast than the control experiment and the experiment using the BDA scheme. The overall results for thesuper typhoon “CHANGMI” show that compared to the control experiments, the CDA sch eme improves the track forecast evidently. The 24-h distance error is reduced from 121 to 89 km and 48-h distance error is from 187 to 179 km. At the same time, the CDA scheme also has a positive impact on the intensity forecast. The RMSE of 24-h minimum sea level pressure is less than 20 hPa which is much less than that of control experiment. The RMSE of 48 h minimum sea level pressure is a little larger thanthat of control experiment. In 2009, GRAPES-TCM based on the CDA scheme was put into quasi-operational run. So far, the performance of the quasi operational system on track and intensity forecasts is better than the present GRAPES TCM opera tional system.
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