本研究目的在探討影響颱風移行速度的機制。本研究篩選在1991-2010年期間，向西與向西北移行的颱風個案中，經過125°-130°E後36小時內，平均移行速度最快10個與最慢10個個案進行分析。
研究結果顯示，較快的個案在軌跡與生成位置有一致性。大多生成於140°E以東，軌跡呈現東南向西北走向，大多往南中國海、菲律賓一帶，生命史較長。較慢的個案則不規則，軌跡較容易經過台灣，因為滯留時間長，所以可能對台灣影響較大。由移行速度的變化可看出環境場駛流對移行速度的影響，較快(慢)的個案大多從生成開始移行速度就很快(慢)。除了環境場駛流外，颱風本身強度產生的β偏移也會影響颱風移行速度。統計結果顯示較慢的個案有90%為非強颱，較快的個案並無明顯的差異。這樣的結果可能與其生成位置相關。
季內振盪亦為影響颱風移行速度的原因之一。颱風移行速度與東西風相位關係顯示，無論是慢或快的個案，很少出現在東風相位，與前人的研究結果一致。較快的個案多發生在西風相位時，季風槽向東延伸，大尺度風場有利颱風西行。較慢的個案多發生在氣候平均時期，風場提供駛流較弱。
本研究進一步透過擾動渦度趨勢方程診斷。較快的個案正渦度趨勢區的位置都比較慢的個案來的遠，強度也較強，使移行速度較快。透過計算發現平流項(VA)與輻散項(VD)在颱風行進上較為重要，其中VA項為最大項，對颱風移行速度貢獻最大。VD項主要貢獻在增加颱風強度，但較快的個案有偏移至颱風移動方向右前方的現象，對颱風移行速度有些微貢獻，顯示對於移動較快的個案，氣旋的移動不完全是動力過程，熱力過程可能也有些影響。
將對颱風移動貢獻最大的VA項分成四小項來分析。結果顯示較快與較慢的個案，平均流造成的擾動渦度平流(VAm)項與beta效應(V-beta)項都呈現向西北傳遞的正渦度平流，代表在颱風向西北移動的移行速度上，駛流扮演重要的角色，強度差異與正渦度趨勢區的遠近，是造成颱風移行速度差異的主因。擾動流造成的平均相對渦度平流(VAe-m)項與VAm及V-beta項呈現反相位，分布上類似但正負相反，抵銷VAm和V-beta項的正貢獻，有減速的作用。本研究結果顯示大尺度環境場和颱風強度，可能是造成颱風移行速度差異的主因。颱風動力與熱力過程均可能影響移動速度。

Camargo, S. J., and A. H. Sobel, 2005: Western North Pacific tropical cyclone intensity and ENSO. J. Climate., 18, 2996-3006.

Chan, J. C. L., and R.T. Williams, 1987: Analytical and numerical studies of the beta-effect in tropical cyclone motion. Part I: Zero mean flow. J. Atmos. Sci., 44, 1257-1265.

____, 2000: Tropical cyclone activity over the Western North Pacific Associated with La Nina event. J. Climate., 13, 2960-2972.

____, Francis M. F. Ko, Ying Man Lei, 2002: Relationship between Potential Vorticity Tendency and Tropical Cyclone Motion. J. Atmos. Sci., 59, 1317–1336.

____, and K. S. Liu, 2004: Global Warming and Western North Pacific Typhoon Activity From an Observational Perspective. J. Climate., 17, 4590-4602.

Chang, C. P., Y. Lei, C. H. Sui, X. Lin, and F. Ren, 2012: Tropical cyclone and extreme rainfall trends in East Asian summer monsoon since mid-20th century. Geophys. Res. Lett., 39, L18702.

Chen, Lianshou, Xu Xiangde, Xie Yiyang, and Li Wen-hong, 1997: The effect of tropical cyclone asymmetric thermodynamic structure on its unusual motion. Chinese J. Atmos. Sci., 21, 83-90.

Chen, T. C., S. Y. Wang, M. C. Yen, and A. J. Clark, 2009: Impact of the intraseasonal variability of the western North Pacific largescale circulation on tropical cyclone tracks. Wea. Forecasting, 24, 646–666.

Chien, F. C., and H. C. Kuo, 2011: On the extreme rainfall of Typhoon Morakot (2009) . J. Geophys. Res., 116, D05104.

Cione, J. J., and E. W. Uhlhorn, 2003: Sea surface temperature variability in hurricanes: Implications with respect to intensity change. Mon. Wea. Rev., 131, 1783–1796.

DeMaria, M., Knaff J. A., and Connell B.H., 2001: A tropical cyclone genesis parameter for the tropical Atlantic. Wea. Forecasting., 16, 219-233.

Elsberry, R.L., 2004: Monsoon-related tropical cyclones in Eats Asia. In ‘East Asian Monsoon’, World Scientific Series on Meteorology of East Asia Vol. 2, Ed. C.-P. Chang, World Scientific, Singapore, 463–498.

Emanuel, K. A., 1999: Thermodynamic contral of hurricane intensity. Nature., 401, 665-669.

_______, C. DesAutels, C. Holloway, and R. Korty, 2004: Environmental control of tropical cyclone intensity. J. Atmos. Sci., 61, 843–858.

_______, 2005: Increasing destructiveness of tropical cyclones over the past 30 years. Nature, 436, 686–688.

_______, S. Ravela, E. Vivant and C. Risi., 2006: A statistical-deterministic spproach to hurricane risk assessment. Bull. Amer. Meteor. Soc., 87, 299-314.

_______, 2008: The hurricane–climate connection. Bull. Amer. Meteor. Soc., 89, ES10–ES20.

Ferreira, Rosana Nieto, Wayne H. Schubert, James J. Hack, 1996: Dynamical Aspects of Twin Tropical Cyclones Associated with the Madden–Julian Oscillation. J. Atmos. Sci., 53, 929–945.

Fiorino, M., and R. L. Elsberry, 1989: Some aspects of vortex structure related to tropical cyclone motion. J. Atmos. Sci., 46, 975-990.

Frank, W. M., and E. A. Ritchie, 2001: Effects of vertical wind shear on the intensity and structure of numerically simulated hurricanes. Mon. Wea. Rev., 129, 2249–2269.

Franklin, C. N., G. J. Holland, and P. T. May, 2006: Mechanisms for the Generation of Mesoscale Vorticity Features in Tropical Cyclone Rainbands. Mon. Wea. Rev., 134, 2649-2669.

Fovell, R. G., K. L. Corbosiero, and H. C. Kuo, 2009: Cloud Microphysics Impact on Hurricane Track as Revealed in Idealized Experiments. J. Atmos. Sci., 66, 1764-1778.

Ge, X. Y., T. Li, S. J. Zhang, and M. Peng, 2010: What causes the extremely heavy rainfall in Taiwan during Typhoon Morakot (2009)?. Atmos. Sci. Lett., 11, 46–50.

Goldenberg, S. B., C. W. Landsea, A. M. Mestas-Nuez, and W. M. Gray, 2001: The recent increase in Atlantic hurricane activity : Causes and implications. Science., 293, 474-479.

Goni, G. J., and J. A. Trinanes, 2003: Ocean thermal structure monitoring could aid in the intensity forecast of tropical cyclones. Eos, Trans. Amer. Geophys. Union, 84, 573–580.

Gray, W. M., 1975: Tropical cyclone genesis. Dept. of Atmospheric Science Paper, 234, Colorado State University, Fort Collins, CO, 121 pp.

____, 1979: Hurricanes: Their formation, structure and likely role in the general circulation. Meteoralogy over the Tropical Oceans, D. B. Shaw, Ed., Royal Meteorological Society, 155-218.

____, 1981: Recent Advances in Tropical Cyclone Research from Rawinsonde Composite Analysis. World Meteorological Organization, 407 pp.

Harr, P. A., and R. L. Elsberry, 1991: Tropical cyclone track characteristics as a function of large-scale circulation anomalies. Mon. Wea. Rev., 119, 1448–1468.

____, and ____, 1995: Large-Scale Circulation Variability over the Tropical Western North Pacific. Part I: Spatial Patterns and Tropical Cyclone Characteristics. Mon. Wea. Rev., 123, 1225–1246.

Hendricks, Eric A., Melinda S. Peng, Bing Fu, Tim Li, 2010: Quantifying Environmental Control on Tropical Cyclone Intensity Change. Mon. Wea. Rev., 138, 3243–3271

Holland, G. J., 1983: Tropical cyclone motion: Environmental interaction plus a β effect. J. Atmos. Sci., 40, 328-342.

______, 1995: Scale interaction in the western Pacific monsoon. Meteor. Atmos. Phys., 56, 52–79.

Holton, J. R., 2004: An Introduction to Dynamic Meteorology. Academic Press, 535 pp.

Hsu, L. H., H. C. Kuo, and R. G. Fovell, 2013: On the Geographic Asymmetry of Typhoon Translation Speed across the Mountainous Island of Taiwan. J. Atmos. Sci., 70, 1006-1022.

Kim, J. H., C. H. Ho, H. S. Kim, C. H. Sui, and S. K. Park, 2007: Systematic Variation of Summertime Tropical Cyclone Activity in the Western North Pacific in Relation to the Madden–Julian Oscillation. J. Climate., 21, 1171-1191.

____, C. C. Wu, C. H. Sui, and C. H. Ho, 2012: Tropical cyclone contribution to interdecadal change in summer rainfall over south China in the early 1990s. Terr. Atmos. Ocean. Sci., 23, 49–58.

Kim, J., C. Ho, H. Kim, C. Sui, and S. K. Park, 2008: Systematic variation of summertime tropical cyclone activity in the western North Pacific in relation to the Madden–Julian oscillation. J. Climate., 21, 1171–1191.

Ko, K. -C., H. -H. Hsu, and C. Chou, 2012: Propagation and Maintenance Mechanism of the TC/Submonthly Wave Pattern and TC Feedback in the Western North Pacific. J. Climate, 25, 8591-8610.

Lau, Kai-Hon, Ngar-Cheung Lau, 1990: Observed Structure and Propagation Characteristics of Tropical Summertime Synoptic Scale Disturbances.Mon. Wea. Rev., 118, 1888–1913.

____, and ____, 1992: The energetics and propagation dynamics of tropical summertime synoptic-scale disturbances. Mon. Wea. Rev., 120, 2523–2539.

Lee, M. H., C. H. Ho, and J. H. Kim, 2010: Influence of tropical cyclone landfalls on spatiotemporal variations in typhoon season rainfall over south China. Adv. Atmos. Sci., 27, 443–454.

Li, R. C. Y., and W. Zhou, 2013a: Modulation of Western North Pacific Tropical Cyclone Activity by the ISO. Part I: Genesis and Intensity. J. Climate, 26, 2904–2918.

____, and ____, 2013b: Modulation of Western North Pacific Tropical Cyclone Activity by the ISO. Part II: Tracks and Landfalls. J. Climate, 26, 2919–2930.

Liebmann, B., and J. D. Glick, 1994: The relationship between tropical cyclones of the western Pacific and Indian Oceans and the Madden– Julian oscillation. J. Meteor. Soc. Japan, 72, 401–411.

Lin, I. I., W. T. Liu, C. C. Wu, J. C.H. Chiang, and C. H. Sui, 2003a: Satellite observations of modulation of surface winds by typhoon-induced upper ocean cooling. Geophys. Res. Lett., 30, 1131.

___, and Coauthors, 2003b: New evidence for enhanced ocean primary production triggered by tropical cyclone. Geophys. Res. Lett., 30, 1718.

___, C. C. Wu, I. F. Pun, and D. S. Ko, 2008: Upper-ocean thermal structure and the western North Pacific category-5 typhoons. Part I: Ocean features and category-5 typhoon’s intensification. Mon. Wea. Rev., 136, 3288–3306.

___, C. H. Chen, I. F. Pun, W. T. Liu, and C. C. Wu, 2009: Warm ocean anomaly, air sea fluxes, and the rapid intensification of tropical cyclone Nargis (2008). Geophys. Res. Lett., 36, L03817.

Maloney, E. D., and M. J. Dickinson, 2003: The intraseasonal oscillation and the energetics of summertime tropical western North Pacific synoptic-scale disturbances. J. Atmos. Sci., 60, 2153-2168.

Nakazawa, T., 1986: Intraseasonal variation of OLR in the tropics during the FGGE year. J. Meteor. Soc. Japan, 64, 17-34.

Peng, M. S., B.-F. Jeng, and R. T. Williams, 1999: A numerical study on tropical cyclone intensification. Part I: Beta effect and mean flow effect. J. Atmos. Sci., 56, 1404–1423.

Pfeffer, R. L., and M. Challa, 1992: The role of environmental asymmetries in Atlantic hurricane formation. J. Atmos. Sci., 49, 1051-1059.

Price, J. F., 1981: Upper ocean response to a hurricane. J. Phys. Oceanogr., 11, 153–175.

Schade, L. R., and K. A. Emanuel, 1999: The ocean’s effect on the intensity of tropical cyclones: Results from a simple coupled atmosphere– ocean model. J. Atmos. Sci., 56, 642–651.

______, 2000: Tropical cyclone intensity and sea surface temperature. J. Atmos. Sci., 57, 3122–3130.

Su, S. H., H. C. Kuo, L. H. Hsu, and Y. T. Yang, 2012: Temporal and Spatial Characteristics of Typhoon Extreme Rainfall in Taiwan. J. Meteor. Soc. Japan, 90, 721-736.

Sobel, Adam H., Christopher S. Bretherton, 1999: Development of Synoptic-Scale Disturbances over the Summertime Tropical Northwest Pacific. J. Atmos. Sci., 56, 3106–3127.

Wang, B., R. L. Elsberry, Y. Wang, L. Wu, 1998: Dynamics in tropical cyclone motion: A review. Chinese. J. Atmos. Sci., 22, 535–547

____, and J. C. L. Chan, 2002: How strong ENSO events affect tropical storm activity over the western North Pacific. J. Climate., 15, 1643-1658.

Wang, Y., and C. C. Wu, 2003: Current understanding of tropical cyclone structure and intensity changes—A review. Meteor. Atmos. Phys., 87, 257–278.

Webster, P. J., G. J. Holland, J. A. Curry, and H. R. Chang, 2005: Changes in tropical cyclone number, duration, and intensity in a warming environment. Science, 309, 1844–1846.

Wu, C. C., K. A. Emanuel, 1993: Interaction of a baroclinic vortex with background shear: Application to hurricane movement. J. Atmos. Sci., 50, 62–76

____, and Y. Kurihara, 1996: A numerical study of the feedback mechanism of hurricane-environment interaction on hurricane movement from the potential vorticity perspective. J. Atmos. Sci., 53, 2264–2282

____, and C.-Y. Lee, and I.-I. Lin, 2007: The effect of the ocean eddy on tropical cyclone intensity. J. Atmos. Sci., 64, 3562–3578.

Wu, L., and B. Wang, 2001: Effects of convective heating on movement and vertical coupling of tropical cyclones: A numerical study. J. Atmos. Sci., 58, 3639–3649.

_____, and _______, 2004: Assessing impacts of global warming on tropical cyclone tracks. J. Climate, 17, 1686-1698.

Wu, Liang, Zhiping Wen, Ronghui Huang, Renguang Wu, 2012: Possible Linkage between the Monsoon Trough Variability and the Tropical Cyclone Activity over the Western North Pacific. Mon. Wea. Rev., 140, 140–150.

Xiang, Jie, and Wu Rongsheng, 2004: The Effect of Asymmetric Wind Structures of Tropical Cyclones on Their Tracks. Acta Meteorologica Sinica,, 19, 52-59.

Zeng, Z., Y. Wang, C. C. Wu, 2007: Environmental Dynamical Control of Tropical Cyclone Intensity—An Observational Study. Mon. Wea. Rev., 135, 38-59.