摘要(英) |
Model for Prediction Across Scales-Atmosphere (MPAS-A) is the new generation global model developed by NCAR. However, the model prediction may not be improved without a good initial field. In order to improve the initial field, this research applies a hybrid system that combines two assimilation systems in which the background is from CWB_GFS, Grid-point statistical Interpolation (GSI) . The hybrid system assimilates the Global Positioning System Radio Occultation (GPSRO) data, including both bending angle and refractivity, in GFS to make a new analysis. The horizontal resolution in GSI-3DVar is T320 (approximately 37.5 km). The vertical resolution of both assimilation systems has 40 levels. Time window of assimilation in this research is 4.5 days, and the new analysis data are used as the initial field for MPAS-A. The horizontal resolution of MPAS-A is a variable resolution of 60-15 km. The higher resolution 15 km is centered is near Taiwan, the higher resolution domain covers East Asia and North Western Pacific.
In this research, we design three kinds of experiments. The first experiment assimilates GTS data, the second experiment assimilates bending angle data (BND) and the third experiment assimilates refractivity data (REF). The first case is Typhoon Soudelor (2015). Time of assimilation is from 0000 UTC 30 July to 1200 UTC 03 August, and the simulation duration is five days from the end of data assimilation with three different analyses. The second case is Typhoon Jelawat with the simulation of three different analyses for five days. At last, we analyze the difference be the initial fields and simulations for these two cases, and discuss the data impacts on the simulations. The tracks with assimilation of BND or REF in Soudelor are better than that with GTS. However, all the experiments over-predict the typhoon intensity. In Jelawat, however, the tracks with both BND and REF are worse than that with GTS. |
參考文獻 |
迮嘉欣,2009:資料同 化對臺灣地區颱風和梅雨模擬之影響。國立中
央大學,大氣物理研究所,碩士論文,80頁。
巫佳玲,2011年:利用WRF 3DVAR 與EAKF 探討GPSRO資料同化對
莫拉克颱風模擬之影響。國立中央大學,大氣物理研究所,碩士論
文,133頁。
黃振星,2011年:同化FORMOSAT-3/COSMIC 及Follow-on 掩星觀測資
料對颱風預報之影響。國立中央大學,大氣物理研究所,碩士論
文,108頁。
陳舒雅,2008年:GPS 掩星觀測資料同化及對區域天氣預報模擬之影
響。國立中央大學,大氣物理研究所,博士論文,153頁。
沈彥志、馮欽賜、陳雯美、曹伶伶、陳御群、楊明仁,2010:以GSI同
化GPSRO資料對中央氣象局全球預報系統之影響。天氣分析與
預報研討會。2010年6月28-30日,臺北,247-252頁。
葉天降、馮欽賜、柳再明、陳得松、黃康寧、陳雯美、汪鳳如、洪景
山,2012年3月: 中央氣象局數值天氣預報作業系統(二) 預報
模式概況。氣象學報第48卷第4期,69-95頁。
吳家苓、陳雯美、沈彥志、吳婉淑, 2009: “GSI 應用於中央氣象局全
球數值預報系統之初步研究”, 2009 天氣分析研討會。
Cucurull, L., J.C. Derber, R. Treadon and R.J. Purser,
2007: Assimilation of Global 26 Positioning System
radio occultation observations into NCEP’s Global
Data Assimilation System. Mon Wea. Rev., 135, 3174-
3193.
Cucurull, L., Y.-H. Kuo, D. Barker, and S. R. H. Rizvi,
2006: Assessing the impact of simulated COSMIC GPS
radio occultation data on weather analysis over the
Antarctic: A case study. Mon. Wea. Rev., 134, 3283-
3296.
Cucurull, L., 2010: Improvement in the use of an
operational constellation of GPS radio occultation
receivers in weather forecasting. Wea. Forecasting,
25, 749–767
Huang, C.-Y., Y.-H. Kuo, S.-H. Chen and F. Vandenberghe,
2005:Improvements on typhoon forecast with
assimilated GPS occultation refractivity. Wea.
Forecasting. 20, 931–953.
Skamarock, W. C., J. B. Klemp, M. G. Duda, L. D. Fowler,
S.-H. Park, and T. D. Ringler, 2012: A multiscale
nonhydrostatic atmospheric model using Centroidal
Voronoi tessellations and C-grid staggering. Mon.
Wea. Rev., 140, 3090–3105.
S.-H. Park, W. Skamarock, J. Klemp, L. Fowler, and M.
Duda, 2013:Evaluation of global atmospheric solvers
using extensions of the
Jablonowski and Williamson baroclinic wave test case.,
Mon. Wea. Rev., 141, 3116-3129
S.-H., J. B. Klemp and W. C. Skamarock, 2014: A
Comparison of Mesh Refinement in the Global MPAS-A
and WRF Models Using an Idealized Normal-Mode
Baroclinic Wave Simulation. Park, Mon. Wea. Rev.,
142, 3614-3634.
Rauscher, S. A., & Ringler, T. D. 2014 : Impact of
Variable-Resolution Meshes on Midlatitude Baroclinic
Eddies Using CAM-MPAS-A., Mon. Wea. Rev, 142(11),
4256–4268. |