研究生: |
張育綾 Chang, Yu-Lin |
---|---|
論文名稱: |
台灣東北海域之黑潮 Kuroshio off northeast Taiwan |
指導教授: |
吳朝榮
Wu, Chau-Ron |
學位類別: |
碩士 Master |
系所名稱: |
地球科學系 Department of Earth Sciences |
論文出版年: | 2007 |
畢業學年度: | 95 |
語文別: | 英文 |
論文頁數: | 53 |
中文關鍵詞: | 黑潮 、颱風 、湧升流 |
英文關鍵詞: | kuroshio, typhoon, upwelling |
論文種類: | 學術論文 |
相關次數: | 點閱:266 下載:36 |
分享至: |
查詢本校圖書館目錄 查詢臺灣博碩士論文知識加值系統 勘誤回報 |
本研究使用一個海洋數值模式、衛星遙測資料以及實測航次資料完成以下研究,台灣東北海域數值模擬研究包含以下兩個部份:南東海陸棚湧升流之季節變化;納莉颱風與黑潮的海氣交互作用。
南東海陸棚湧升流為全年湧升的現象,不同季節受到不同機制影響呈現的季節變化趨勢也不相同,由表層積分至100米的平均垂直速度主要受黑潮擺動影響,夏天當黑潮遠離台灣東岸時,湧升較強,冬天黑潮入侵東海陸棚抑制了湧升流發展,於是湧升較弱,由表層至30米的垂直速度受當地風場的影響,冬天湧升較夏天強。
納莉颱風與黑潮之間存在著海氣交互作用,納莉颱風數度穿越黑潮使得其強度多次變化,當颱風行經黑潮北邊時,海洋形成了一個渦漩,在黑潮上與黑潮南邊則沒有觀察到此現象,原因來自受到黑潮強勁流速影響以及地形限制。當颱風行進速度緩慢時,能影響的海洋深度也較大,此外颱風也在海洋留下了震盪的現象,此現象由周期判定為為近慣性震盪。在海表面溫度圖當中所看到的冷水海域則是颱風過後所造成的湧升現象,由衛星測葉綠素甲圖以及海表面溫度圖得知,此湧升現象確實將次表層較冷與富營養鹽的海水帶至表層。
Kuroshio off northeast Taiwan has been studied using a numerical ocean model and available observations. Particularly, the seasonal variability of upwelling near the southern East China Sea shelf and the interaction between typhoon Nari and Kuroshio have been extensively investigated.
Based on model simulation, the vertical velocity in the upwelling region is positive in all months, indicating the upwelling is a year-round phenomenon. Furthermore, opposite seasonal tendencies of upwelling are found for different depth range. The vertical velocity integrated from surface to 100 m is weaker in winter than in summer, whereas it reaches its minimum during summertime in the top 30 m. Different mechanisms are responsible for this seasonal discrepancy. Seasonality in the upper 100 m is influenced by the Kuroshio migration. In winter, Kuroshio intrudes onto the shelf and prevents the upwelling developing, and therefore vertical velocity is weaker. As Kuroshio retreats from the shelf in summer, vertical velocity becomes stronger. On the other hand, seasonal tendency in the top 30 m is attributed to the local wind speed that is generally weaker in summer but becomes much stronger during winter.
We also use the model results and satellite data to discuss the interaction between Typhoon Nari and Kuroshio. Nari ambled around and crossed Kuroshio several times, which causes variations in typhoon intensity. Model simulation suggests that a cyclonic eddy triggered by Nari has occurred in regions north of Kuroshio, as a result, the cold SST patch is only visible to the north of the Kuroshio axis. The cyclonic circulation penetrates much deeper for a slowly-moving storm, regardless of the typhoon intensity. Near-inertial frequency oscillations after typhoon departure are simulated by the model in terms of the vertical displacement of isotherms. The SST cooling caused by upwelling and vertical mixing is effective in cooling the upper ocean several days after the storm has passed. At certain locations, surface chlorophyll a concentrations increase significantly after Nari’s departure. Upwelling and mixing bring nutrient-rich subsurface water to the sea surface, causing enhancement of phytoplankton bloom.
Blumberg, A. F. and G. L. Mellor (1987): A description of a three -dimensional coastal ocean circulation model. In: Heaps, N.S. (Ed.), Coastal and Estuarine Sciences 4: Three Dimensional Coastal Models. AGU, Washington, DC, 1-16p.
Chao, S. -Y. (1991): Circulation of the East China Sea, a numerical study. Journal of Oceanographic Society of Japan, 42, 173-295
Chern, C. S., and J. Wang (1989): On the water mass at northern offshore area Taiwan, Acta Oceanogra. Taiwanica, 22, 14-32.
Chen, C. T. A. (1996): The Kuroshio intermediate water is the major source of nutrients on the East China Sea continental shelf. Oceanol. Acta, 5, 523-527
Chung, S. –W., S. Jan, and K. K. Liu (2001): Nutrient fluxes through the Taiwan Strait in spring and summer 1999. J. Oceanogr., 57, 47 – 53.
Fan, K. L. (1980): On the upwelling off northeastern shore of Taiwan, Acta Oceanogra. Taiwanica, 11, 105-117.
Gilson, J., and D. Roemmich (2002): Mean and temporal variability in Kuroshio geostrophic transport south of Taiwan (1993 - 2001), J. Oceanogr., 58, 183 – 195.
Gong, G. C., F. K., Shiah, K. K., Liu, and et al. (1997): Effect of Kuroshio intrusion on the chlorophyll distribution in the southern East China Sea north of Taiwan during Spring, 1993, Continental Shelf Res., 17, 79-94
Hsu, D. Y. (2005): The temporal-spatial variation of bacterioplankton in the upwelling region, East China Sea, master thesis, Institute of Oceanography in National Taiwan University (in Chinese).
Jan, S. and S. -Y. Chao (2003): Seasonal variation of volume transport in the major inflow region of the Taiwan Strait: the Penghu Channel, Deep Sea Res., Part II, 50, 1117 - 1126.
Liang, W. -D., T. Y. Tang, Y. J. Yang, and et al. (2003): Upper-ocean currents around Taiwan, Deep Sea Res., Part II, 50, 1085 - 1105.
Lin, S. F., T. Y. Tang, S. Jan, and C. –J. Chen (2005): Taiwan Strait current in winter. Continental Shelf Res., 25, 1023-1042.
Lin, I. -I, W. T. Liu, C. -C. Wu, G. T. F. Wang, and et al. (2003): New evidence for enhanced ocean primary production triggered by tropical cyclone. Geophys. Res. Lett., 30, 1718, doi:10.1029/2003GL017141.
Lin, I. -I, C. -C. Wu, K. A. Emanuel, I. -H. Lee, and et al. (2005): The interaction of Supertyphoon Maemi (2003) with a warm ocean eddy. Mon. Wea. Rev., 133, 2635–2649.
Liu, K. K., G. C., Gong, S. W., Lin, and et al. (1992): The year-round upwelling at the shelf break near the northern tip of Taiwan as evidenced by chemical hydrography. Terrestrial, Atmospheric and Oceanic Sciences, 3, 243-276
Milliff, R. F., W. G. Large, J. Morzel, and et al. (1999): Ocean general circulation model sensitivity to forcing from scatterometer winds. J. Geophys. Res., 104, 11337 – 11358.
Nitani, H. (1972), Beginning of the Kuroshio, in Kuroshio - Its physical aspects, pp. 129 - 163, edited by H. Stommel and K. Yoshida, Univ. of Tokyo Press, Tokyo.
Powell, M. D., P. J. Vickery, and T. A. Reinhold (2003): Reduces drag coefficient for high wind speeds in tropical cyclones. Nature, 422, 279-283
Price, J. F. (1981), Upper ocean response to a hurricane, J. of Phys. Oceanogr., 11, 153– 175.
Shay, L.K., G.J. Goni and P.G. Black (2000), Effects of a warm oceanic feature on hurricane Opal. Mon. Wea. Rev., 128, 1366-1383.
Tang, T. Y., J. H. Tai, and Y. J., Yang (2000): The Flow Pattern north of Taiwan and the migration of the Kuroshio. Continental Shelf Res., 20, 349-371.
Tseng, C. M., G. T. F. Wong, I. I. Lin, C. R. Wu, and K. K. Liu (2005): A unique seasonal pattern in phytoplancton biomass in low-latitude waters: wind-reinforced (monsoon-induced) winter convective overturn in the South China Sea. Geophys.Res. Lett., 32, L08608, doi:10.1029/2004GL022111
Wang, Y. –H., L. –Y. Chiao, K. M. M. Lwiza, and D. –P. Wang (2004): Analysis of flow at the gate of Taiwan Strait. J. Geophys. Res., 109, C02025, doi:10.1029/2003JC001937.
Wu, C. -R. and Y. C. Hsin (2005): Volume transport through the Taiwan Strait : a numerical study. Terrestrial, Atmospheric and Oceanic Sciences, Vol. 16, No. 2, 377-391.
Wu, C. -R. and H. F. Lu (2007): A numerical study on the formation of the upwelling off northeast Taiwan (submitted to J. Geophys. Res.)
Wyrtki, K. (1961): Physical oceanography of the southeast Asian waters, Scientific Results of Marine Investigation of the South China Sea and the Gulf of Thailand. NAGA Report Vol. 2, Scripps Institution of Oceanography, La Jolla, California, 195pp.
Yuan, Y. J. Su and Z. Pan (1991): A study of the Kuroshio in the East China Sea and the currents east of the Ryukyu Island in 1998. In Takano, K. (Ed.), Oceanography of Asian Marginal Seas, Elsevier, Amsterdam, 305-320
Zhang, D., T. N. Lee, W. E. Johns, and et al. (2001): The Kuroshio east of Taiwan: Modes of variability and relationship to interior ocean mesoscale eddies, J. Phys. Oceanogr., 31, 1054 - 1074.