本研究分析過去62年（1945～2006年）西北太平洋地區颱風活動之年代際（Interdecadal）變化，發現經過十一年滑動平均後，秋強颱呈現明顯的年代際變化，秋強颱活躍期（1990～1994年）颱風生成個數較多，且發展成強颱的比率（Ratio of strong typhoon, RST）較高，達33.8％，秋強颱非活躍期（1974～1978年）則相反，其RST僅19.6％。西北太平洋地區秋強颱活躍與否，和西北太平洋海溫較無明顯相關，反而強烈受到中～東太平洋地區海溫之影響。活躍期中～東太平洋海溫高，暖水厚度大，秋颱生成區向東南延伸至國際換日線一帶，生命期較長，非活躍期反之，秋颱均形成在160°E以西的區域，生命期較短。活躍期中～東太平洋暖海溫伴隨較高的環境水汽含量值，於暖水團的西北側低對流層出現氣旋式異常環流，高對流層出現反氣旋式異常環流，垂直風切減小，有利強烈颱風的生成與發展。

本文進一步藉由IPCC-AR4海氣耦合模式20C3M資料與現今實際觀測資料作比對，探討全球暖化後秋強颱強度變化的趨勢，顯示高解析度模式年代際變化大致和觀測相似，其變化趨勢和振幅相仿，可作為預測與秋強颱參考的指標。

Tropical storm (TS) activity has strong impacts on the weather and climate over western North Pacific (WNP) Ocean. This study found that the activity of strong (categories 4-5) typhoon exhibits significant interdecadal variability, while the signal of interdecadal variability of categories 1-3 typhoon is not obvious. Since TS events in summer have received considerable attention, recently, this study focuses on the interdecadal variability of super typhoon activity in autumn. The ratio of the number of strong typhoon to the total number of typhoon (RST) in autumn is 29.3％. The RST during the strong typhoon active and inactive period are 33.8％ and 19.6％ respectively. The strong typhoon activity over the WNP Ocean in autumn is strongly influenced by the large-scale environment change over the central-eastern Pacific Ocean. During active period the warm sea surface temperature (SST) and high moisture content occur over the central-eastern Pacific Ocean. These conditions lead the formation of strong typhoon to extend south-eastward to the Date Line. On the contrary, the formation area of strong typhoon is restricted to the west of 160°E during inactive period. Thus, the strong typhoons have longer (shorter) journey and life span on the warm ocean during active (inactive) period. The interdecadal variability of the thermodynamic condition over the central Pacific is curial to the interdecadal change of strong typhoon in autumn over WNP Ocean. This study will further investigate the IPCC AR4 air-sea coupled model simulation to estimate the trend of strong typhoon after global warming.

Atkinson, G. D., and C. R. Hollidy, 1977: Tropical cyclone minimum sea level pressure maximum sustained wind relationship for the western North Pacific. Mon. Wea. Rev., 105, 421-427.

Baik, J. -J., and J. S. Paek, 2001: Relationship between vertical wind shear and typhoon intensity change, and development of three predictor intensity prediction model. J. Meteor. Soc. Japan., 79, 695-700.

Barnett, T. P., D. W. Pierce, R. Schnur, 2001: Detection of Anthropogenic Climate Change in the World’s Oceans. Science, 292, 270-274.

------, D. W. Pierce, K. M. AchutaRao, P. J. Gleckler, B. D. Santer , J.M. Gregory, W.M. Washington, 2005: Penetration of Human-Induced Warming into the World’s Oceans. Science, 309, 284- 287.

Bottomley, M., et al., 1990: Global Ocean Surface Temperature Atlas “GOSTA”. HMSO, London, 20 pp.

Broccoli, A. J. and S. Manable, 1990: Can existing climate models be used to study anthropogenic changes in tropical cyclone climate? Geophys. Res. Lett., 17, 1917-1920.

Camargo, S. J., A.H. Sobel, 2005: Western North Pacific Tropical Cyclone Intensity and ENSO. J. Climate, 18, 2996-3006.

Chan, J. C. L., 1985: Tropical cyclone activity in the Northwest Pacific in relation to the El Nino/ Southern Oscillation phenomenon. Mon. Wea. Rev., 113, 599-606.

------,and J. E. Shi, 1996: Long-term trends and interannual variability in tropical cyclone activity over the western North Pacific. Geophys. Res. Lett., 23, 2765- 2767.

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

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

------,2006: Comment on” Change in Tropical Number, Duration, and Intensity in a Warming Environmen”. Science, 311，1713b.

Chang, C. P., Y. Zhang, and T. Li, 2000: Interannual and Interdecadal Variations of the East Asian Summer Monsoon and Tropical Pacific SSTs, Part I: Roles of the Subtropical Ridge, J. Climate, 13, 4310-4325.

Chao, Y., M. Ghil, X. Li, and J. C. McWilliams, J. C., 2000: Pacific Interdecadal Variability in This Century's Sea Surface Temperatures. Geophys. Res. Lett., 27, 2261-2272.

Chauvin, F., J.-F. Royer, and M. Déqué, 2006: Response of hurricane-type vortices to global warming as simulated by ARPEGE-Climat at high resolution. Clim. Dyn., 27, 377–399.

DeMaria, M., and J. Kaplan, 1994: Sea surface temperature and maximum intensity of Atlantic tropical cyclones. J. Climate., 7, 1324-1334.

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

Emanuel, K. A.,1986: An air-sea interaction theory for tropical cyclones. Part I: Steady-state maintenance. J. Atmos. Sci., 43, 585-604.

------, 1991: The theory of hurricanes. Annu. Rev. Fluid Mech., 23, 179-196.

------, 1999: Thermodynamic control of hurricane intensity. Nature, 401, 665-669.

------, 2000: A Statistical Analysis of Tropical Cyclone Intensity. Mon. Wea. Rev., 128, 1139-1152.

------, K. C. DesAutels, C. Holloway, and R. Korty, 2004: Environmental control of tropical cyclones intensity. J. Atmos. Sci., 61, 843-858.

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

Gettelman, A., D. J. Seidel, M. C. Wheeler, and R. J. Ross, 2002: Multidecadal trends in tropical convective available potential energy. J. Geophys. Res. 107, 4606- 4613.

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

Gong, D. Y., and C. H. Ho, 2002: Summer rainfall shift over Yangtze River valley in the late 1970s. Geophys. Res. Lett., 29, 10.1029/2001GL014523.

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., 1968: Global view of the origin of tropical disturbances and storms. Mon. Wea. Rev., 96, 669-700.

------, 1977: Tropical Cyclone Genesis in the Western North Pacific. J. of Meteor. Soc. Of Japan., 55, 465-481.

Haarsma, R. J., J. F. B. Mitchell, and C. A. Senior, 1993: Tropical disturbances in a GCM. Ckimate Dyn.,8, 247-257.

Hasegawa, A., and S. Emori, 2005: Tropical cyclones and associated precipitation over the western North Pacific: T106 atmospheric GCM simulation for present-day and doubled CO2 climates. Scientific Online Letters on the Atmosphere, 1, 145–148.

Henderson-Sellers, A., H. Zhang, G. Berz, K. A. Emanuel, W. M. Gray, C. Landsea, G. J. Holland, S-L. Lighthill, P. Webster, and K. McGuffie, 1998: Tropical cyclone and global climate change: A Post-IPCC Assessment Bull. Amer. Meteor. Soc., 79, 19-38.

Ho, C. H., J. J. Baik, J. H. Kim, D. Y. Gong, C. H. Sui, 2004: Interdecadal Change in Summerime Typhoon Track. J. Climate., 17, 1767-1776.

Holland, G. J., 1997: The Maximum Potential intensity of Tropical Cyclone. J. Atmos. Sci. 54, 2519-2540.

Hoyos, C. D., P. A. Agudelo, P.J. Webster, J. A. Curry, 2006: Deconvolition of the Factors Contributing to the Increase in Global Hurricane Intensity, Science, 312, 94-97.

Knaff J. A., C. R. Sampson, and M. DeMaria, 2005: An operational statistical typhoon intensity prediction scheme for the NWP. Wea. Forecasting, 20, 688-699.

Knutson, T. R., R. E. Tuleya, Y. Kurihara, 1998: Simulated Increase of Hurricane Intensities in a CO2-Warmed Climate. Science, 279,1018-1020.

-----, and R. E. Tuleya, 1999: Increased hurricane intensities with CO2-induced warming as simulated using the GFDL hurricane prediction system. Climate Dyn., 15, 503–519.

——, R. E. Tuleya, W. Shen, and I. Ginis, 2001: Impact of CO2-induced warming on hurricane intensities as simulated in a hurricane model with ocean coupling. J. Climate, 14, 2458–2468.

------, and R.E. Tuleya, 2004: Impact of CO2-induced warming on simulated hurricane intensity and precipitation: Sensitivity to the choice of climate model and convective parameterization. J. Climate, 17, 3477-3495.

------, T. L. Delworth, K. W. Dixon, I.M. Held, J. Lu, V. Ramaswamy, M. D. Schwarzkopf, G. Stenchikov, and R.J. Stouffer, 2006: Assessment of Twentieth-Century Regional Surface Temperature Trends Using the GFDL CM2 Coupled Models. J. Climate, 19, 1624-1951.

Krishnamurti, T. N., R. Correa-Torres, M. Latif, and G. Danghenbaugh, 1998: The impact of current and possibly future sea surface temperature anomalies on the frequency of Atlantic hurricanes. Tellus., 50A, 186-210.

Landesea, C. W., N. Nicholls, W. M. Gray, and L. A. Avila, 1996: Downward treads in the frequency of intense Atlantic hurricanes during the past five decades. Geophys. Res. Lett., 23, 1697-1700.

Latif, M., N.Keelyside, and J.Bader, 2007: Tropical sea surface temperature, vertical wind shear, and hurricane development. Geophys. Res. Lett., 34, L01710. doi: 10.1029 /2006GL027969.

Levitus S., J. I. Antonov, J. Wang, T. L. Delworth, K. W. Dixon, A. J. Broccoli, 2001: Anthropogenic Warming of Earth’s Climate System. Science, 292, 267-270.

Lin, I.-I., C.-C. Wu, K. A. Emanuel, I.-H. Lee, C.-R. Wu, and I.-F.Pum, 2005: The interaction of Supertyphoon Maemi with a warm ocean eddy. Mon. Wea. Rev., 133, 2635–2649.
Maloney, E. D., and D. L. Hartmann, 2000: Modeulation of hurricane activity in the Gulf of Mexico by the Madden-Julian Oscillation. Scirnce, 287, 2002-2004.

------, and ------, 2001: The Madden-Julian Oscillation, Barotropic Dynamics, and North Pacific Tropical Cyclone Formation. Part I: Observations. J. Atmos. Sci., 58, 2545-2558.

Mantua, N. J., S. R. Hare, Y. Zhang, J. M. Wallace, and R. C. Francis, 1997: A Pacific interdecadal climate oscillation with impacts on salmon production. Bull. Amer. Meteor. Soc., 78, 1069-1079.

McBride, J. L., and R. M. Zehr, 1981: Observational analysis of tropical cyclone formation, Part II: Comparison of non-developing versus developing systems. J. Atmos. Sci., 38, 1132-1151.

McDonald, R.E., D.G. Bleaken, D. R. Cresswell, V. D. Pope, C. A. Senior , 2005: Tropical storms: Representation and diagnosis in climate models and the impacts of climate change. Clim. Dyn., 25, 19–36.

Meehl, G.A., T.F. Stocker, W.D. Collins, P. Friedlingstein, A.T. Gaye, J.M. Gregory, A. Kitoh, R. Knutti, J.M. Murphy, A. Noda, S.C.B. Raper,I.G. Watterson, A.J. Weaver and Z.-C. Zhao, 2007: Global Climate Projections. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S.,D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Molinari, J., K. Lombardo, and D. Vollaro, 2007: Tropical Cyclogenesis within an Equatorial Rossby Wave Packet. Amer. Meteor. Soc., 64, 1301-1317.

Nguyen, K.C., and K.J.E. Walsh, 2001: Interannual, decadal, and transient greenhouse simulation of tropical cyclone-like vortices in a regional climate model of the South Pacific. J. Clim., 14, 3043–3054.

Norris, J. R., 2000: Interannual and Interdecadal Variability in the Storm Track, Cloudiness, and Sea Surface Temperature over the Summertime North Pacific. J. Climate., 13, 422-430.

Oouchi, K., et al., 2006: Tropical cyclone climatology in a global-warming climate as simulated in a 20km-mesh global atmospheric model: Frequency and wind intensity analyses. J. Meteorol. Soc. Japan, 84, 259–276.

Rayner, N. A., E. B. Horton, D. E. Parker, C. K. Folland, and R. B. Hackett, 1996:
Version 2.2 of the Global sea-Ice and Sea Surface Temperature data set, 1903-1994, CRTN 74, Hadley Centre, UKMO.

Santer, B. D.,T. M. L. Wigley, P. J. Gleckler, C. Bonfils, M. F. Wehner, K. AchutaRao, T. P. Barnett, J.S. Boyle, W. Bruggemann, M. Fiorino, N. Gillett, J. E. Hansen, P. D. Jones, S.A. Klein, G. A. Meehl, S. C. B. Raper, R. W. Reynolds, K. E. Taylor, and W. M. Washington, 2006: Forced and unforced ocean temperature changes in Atlantic and Pacific tropical cyclogenesis regions, PNAS, 103,13905-13910.

Shay, L. K., G. I. Goni, and P. G. Black, 2000: Effects of a warm oceanic feature on Hurricane Opal. Mon. Wea. Rev., 128, 1366–1383.

Sobel, A.H., and C.S. Bretherton,1999: Development of synoptic-scale disturbances over the summertime tropical north-west Pacific. J. Atmos. Sci., 56, 3106-3127.

Sugi, M., A. Noda, and N. Sato, 2002: Influence of the global warming on tropical cyclone climatology: An experiment with the JMA global model. J. Meteorol. Soc. Japan, 80, 249–272.

------, and J. Yoshimura, 2004: A mechanism of tropical precipitation change due to CO2 increase. J. Clim., 17, 238–243.

Trenberth, K.E., P.D. Jones, P. Ambenje, R. Bojariu, D. Easterling, A. Klein Tank, D. Parker, F. Rahimzadeh, J.A. Renwick, M. Rusticucci, B. Soden and P. Zhai, 2007: Observations: Surface and Atmospheric Climate Change. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Tsutsui, J., 2002: Implications of anthropogenic climate change for tropical cyclone activity: A case study with the NCAR CCM2. J. Meteorol. Soc. Japan, 80, 45–65.
Tuleya, R. E., and Y. Kurihara, 1981: A numerical study on the effects of environmental flow on the tropical storm genesis. Mon. Wea. Rev.,109, 2487- 2506.
Walsh, K. J. E., and B. F. Ryan, 2000: Tropical Cyclone Intensity Increase near Australia as a Result of Climate Change. J. Climate, 13, 3029-3036.

Wang, B., 1995: Interdecadal Changes in El Nino Onset in the Last Four Decades. J. Climate., 8, 267-285.

------,R. Wu, and X. Fu, 2000: Pacific-East Asia teleconnection: How does ENSO affect East Asian climate? J. Climate, 13, 1517-1536.

------, and J. C. L. Chan, 2002: How Strong ENSO Events Affect Tropical Storm Activity over the Western North Pacific. J. Climate, 15, 1643-1658

Watson, R. T., the Core Writing Team, Eds., 2001: Climate Change 2001: Synthesis Report, Cambridge University Press, 398pp.

Webster, P. J., G. J. Holland, J. A. Curry, and H.-R. Chang, 2005: Change in Tropical Number, Duration, and Intensity in a Warming Environmen. Science, 308，1753-1754.

------, J. A. Curry, P. J., G. J. Holland, 2006: Response to Comment on” Change in Tropical Number, Duration, and Intensity in a Warming Environmen”. Science, 311, 1713c.

Wu, C-. C., C.-Y. Lee, and I.-I Lin , 2007: The Effect of the Ocean Eddy on Tropical Cyclone Intensity, J. Atmos. Sci., 64, 3562-578.

Wu, L., and B. Wang, 2004: Assessing impacts of global warming on tropical cyclone tracks. J. Clim., 17, 1686–1698.

Wu, M-. C., K-. H. Yeung, and W-. L. Chang, 2006: Trends in Western North Pacific Tropical Cyclone Intensity, EOS, 87, 537-538.

Xue,Y., T. M. Smith, and R. W. Reynolds, 2003: Notes and Correspondence- Interdecadal Changes of 30-Yr SST Normal during 1871-2000.J.Climate, 16, 1601-1612.

Yoshimura, J., and M. Sugi , 2005: Tropical cyclone climatology in a high- resolution AGCM: Impacts of SST warming and CO2 increase. Scientific Online Letters on the Atmosphere, 1, 133–136.

------, ------, and A. Noda, 2006: Influence of greenhouse warming on tropical cyclone frequency. J. Meteorol. Soc. Japan, 84, 405–428.

Yumoto, M., and T. Matsuura, 2001: Interdecadal Variability of Tropical Cyclone Activity in the Western North Pacific. J. Meteor. Soc. Japan, 79, 23-35.

Zhang, Y., J. M.Wallace, and D.S. Battisti, 1997: ENSO-like Interdecadal Variability: 1900-93. J. Climate., 10, 1004-1020.