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大氣科學
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| 篇名 | 利用MM5 4DVAR模式探討同化虛擬渦旋和掩星折射率資料對於珊珊颱風(2006)數值模擬之影響 |
|---|---|
| 卷期 | 40:2 |
| 並列篇名 | The Impact of Assimilation with a Bogus Vortex and Radio Occultation Refractivity Data on Simulation of Typhoon Shanshan (2006) Using MM5 4DVAR |
| 作者 | 黃清勇 、 吳俊澤 |
| 頁次 | 153-170 |
| 關鍵字 | 四維變分 、 虛擬資料同化 、 GPS掩星折射率 、 4DVAR 、 Bogus Data Assimilation 、 GPS RO Refractivity |
| 出刊日期 | 201209 |
中文摘要
本研究利用MM5 4DVAR模式，探討渦旋的虛擬資料同化(Bogus Data Assimilation, BDA)和GPS掩
星觀測資料同化對於初始分析場的改進及颱風預報的影響，模擬個案為珊珊颱風(2006)。本文的 BDA
包括氣旋的海平面氣壓及三維平衡風場與近地面徑向入流，可以有效地強化模式初始颱風，更能幫助維
持颱風垂直結構，模擬結果顯示對颱風預報有明顯的改善。
個案實驗結果顯示，加入 GPS 掩星折射率資料可以修正模式初始場，只是調整的輻度遠不及虛擬
渦旋同化大。個案模擬結果亦顯示，虛擬渦旋同化主導颱風的路徑及強度預報，遠較無同化時要好很多，
而僅同化GPS 掩星折射率在路徑預報亦有一些的影響。同時同化虛擬渦旋及折射率，則較單純BDA在
路徑預報上可進一步改善，同時亦改善台灣地區的劇烈降雨預報。
英文摘要
This study employs the MM5 4DVAR to investigate influences of assimilation with GPS radio
occultation (RO) data and a bogus vortex on initial analysis and prediction of Typhoon Shanshan (2006). In
this study, the bogus data assimilation (BDA) includes sea-level pressure, 3-D wind, and surface balanced
gradient wind and radial inflow component of a symmetric cyclone. The BDA appears helpful to intensify
the initial typhoon and maintain its vertical structure.
Results of the experiments show that assimilation with GPS refractivity data improves the initial field in
the vicinity of the RO surroundings but with smaller magnitudes as compared to those from the BDA which
significantly improves the weak initial typhoon vortex from the control experiment without BDA.
Assimilation with GPS refractivity data only has some minor impacts on the track and intensity prediction.
However, the combined assimilation with both GPS refractivity data and a bogus vortex further improves the
track from BDA only. This in turns improves the skill scores on prediction of severe rainfall over Taiwan.