教師著作
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Item 南海之物理-生物耦合模式研究(I)(行政院國家科學委員會, 2002-10-31) 吳朝榮; 劉康克Item 南海之物理-生物耦合模式研究(II)(行政院國家科學委員會, 2003-07-31) 吳朝榮; 劉康克Item 西北太平洋颱風潛熱(Tropical Cyclone Heat Potential TCHP)之研究(2004-05-20) 潘任飛; 林依依; 吳朝榮在近來的研究中有相當多的證據顯示颱風強度的增加與海洋中的暖特徵現象 (warm oceanic features)有關，並且利用颱風潛熱(TCHP)來代替傳統的海水表 面溫度(SST)來研究颱風的強度(Shay 2000, Goni & Trinanes 2003)，因為 SST只能代表的海水表面溫度而無法代表上層海洋的垂直結構(Upper ocean thermal structure)，因此TCHP能夠清楚地描述海洋的暖特徵，如暖渦(warm core ring, WCR)；早在1972年Leipper就把TCHP 定義出來，但由於當時沒有衛 星資料的幫助，一直無法運用，直到近年由於衛星遙測的進步，才被開始被應用 ，TCHP的定義是從海面到26度C等溫線的垂直溫度積分，如下：Q/sub H/(x,y,t)=.rho.C/sub p/.int./sup 0//sub (Y=26)) .DELTA.T(x,y,z,t)dz每 年有不少的強烈颱風在西北太平洋(Northwest Pacific Ocean, NWPO)產生出來 ，但目前全球對颱風強度的預測並不是很理想，因此藉著研究NWPO的TCHP和 TCHP與颱風之間的關係來提昇我們對颱風強度之預測。本研究是採用美國海軍實 驗室(US Naval Research Laboratory)所發展的三維數值模式(NPACNFS, North Pacific Ocean Nowcast/Forecast System)，此模式是修改自Princeton Ocean Model (Blumberg and Mellor, 1987)，使模式能作資料同化(data assimilation)，其作同化的資料有T/P的SSHA和由衛星所得到的海表面溫度 (SST)。整個太平洋模式蓋了16度S~60度N，99度E~77度W的區域，而模式的垂直 解析度是用26層的sigma-levels組成，在上層海洋的分層數比較密，所以此模式 對上層海洋的解析度比較高，有利於對上層海洋的研究。利用此模式的結果，可 以算出北太平洋的TCHP。本研究並把由NPACNFS 和由美國大氣海洋總署(AOML)利 用來two-layer reduced gravity model 計算出來2003 年夏天的TCHP作比較。Item 臺灣附近海域傳輸量之研究(2004-05-20) 許瑋真; 辛宜佳; 吳朝榮臺灣位於西北太平洋(Northwestern Pacific Ocean )的海域上，是東亞島弧的 一部份；東連太平洋，北鄰東海(East China Sea，ECS)，西接臺灣海峽(Taiwan Strait)，南靠呂宋海峽(Luzon Strait)，西南方為南中國海(South China Sea，SCS)。在此區域之風系概為：於冬季時低氣壓在北太平洋上形成，盛行東 北季風，然於夏季時相反，盛行西南季風，故此季風系統的改變乃是影響臺灣附 近海流變化的重要因子之一。臺灣周圍海底地貌有許多重要的通道，這些通道為 水團交換的重要場所，黑潮由臺灣東邊的東臺灣通道(East Taiwan Channel， ETC)進入東海，西太平洋水團經由臺灣與呂宋島間的呂宋海峽與南中國海水團會 合，東海水團流經位在臺灣與中國大陸(Mainland China)間的臺灣海峽與南中國 海水團相會，而在臺灣海峽東南側的澎湖水道(Penghu channel)，是海峽中唯一 水深超過200 公尺之處。所以這些通道影響著水團進出的特性，而且從過去到現 在已有計畫展開研究。本研究的主要目的是運用臺灣附近海域傳輸量之比較來驗 證西北太平洋數值模式的正確性，並探討此海域附近傳輸量的變異。由西北太平 洋數值模式之模擬結果，我們可以計算出臺灣附近海域各主要通道之傳輸量的時 間序列，其結果與觀測值相仿，如黑潮主軸在PN測線(124.50度E,30.00度 N)~(128.25度E，27.50度N)上往東北方向的流，年平均傳輸量為 26.7.plmin.3.5Sv(1Sv=10m/sup 3/s/sup -1/)，與Ichikawa and Chean(2000)指出年平均傳輸量為27.6Sv，頗為近似，故可說明此模式在臺灣附 近海域的模擬具有很高的可信度。Item Surface Circulation in the East China Sea(2004-05-20) Hsin, Yi-Chia; Wu, Chau-Ron; Liang, Wen-DerItem Fine-Resolution Modeling Studies in the Northern South China Sea(2004-05-20) Wu, Chau-Ron; Hsin, Yi-Chia; Jiang, Tzu-LingRecently, there have been many new observations from expeditions and moored instruments in the northern South China Sea (NSCS), which produced several exciting new features not known before. These new findings call for a new generation of models to explore the processes responsible for these features, because most of the existing numerical models can not either resolve them or account for the physics behind them. A fine-resolution, hydrodynamic model of the NSCS area capable of resolving the temporal and spatial scales of corresponding oceanic processes and bringing together the unique oceanographic data sources available in this area is established in this study. The fine-resolution NSCS model is nesting to a North Pacific Ocean model. Description of the circulation is further improved by assimilating the TOPEX/Poseidon satellite altimeter data into the NSCS model. Data assimilation model not only reproduces the seasonal patterns in the earlier studies but also resolves mesoscale highs and lows in the region. The model results are reasonably consistent with the limited observations during previous expeditions. The spatial and temporal variations in the NSCS are discussed as well. Furthermore, satellite remote sensing data and time series data obtained from moored instruments (SEATS) will be also used for comparison with model output.Item 颱風對海洋溫度場與流場之影響---數值模式研究(2004-05-20) 梁文德; 吳朝榮; 莊文思; 唐存勇; 楊穎堅此研究所採用之海洋數值模式為美國邁阿密大學發展的海洋數值模式 MICOM(Miami Isopycnic Coordinate Ocean Model0，模式範圍為95度E-160度 E及20度S-45度N，水平解析度約0.25度。模式結果已成功運用於南海，用以解釋 1997-2001年間南海海洋溫度場與流場之年變化、年際變化、1997/1998 聖嬰事 件影響及黑潮於呂宋海峽入侵南海之動力機制。此次研究利用上述結果，改以解 析度為0.5度*0.5度的QSCAT(NASA Quick Scatterometer；1999/09-2003/120衛 星風場資料積分，探討西太平洋颱風對海洋溫度場與流場之影響。初期以日平均 風場所驅動之模式結果顯示，SST下降約2-7度C，溫度下降程度取決於颱風風場 之對稱性、強度與移動速度，以及海洋斜溫層深度與颱風前之SST。其中若颱風 風場呈現明顯之不對稱性時，雖為強烈颱風，其在開闊海洋(open ocean0不易造 成顯著之SST下降，只能使海流水平速度增強，而無法形成有效之水平輻散 (horizontal divergence0作用，產生Ekman Pumping效應。而當颱風引起 Ekman Pumping 效應時，深度可至500m以上，SST下降現象往往可維持一週以上。相反 地，若SST產生明顯之下降，颱風強度則易於減弱。另以Wukong颱風 2000/09/05-2000/09/10經過南海時為例，SST於颱風經過後，溫度最大降低約 7-8度C，雖與衛星SST 觀測結果相似，但因其為日平均風場所驅動之結果，部分 區域SST 下降程度與觀測值仍有差異，而颱風實際路徑則呈反時鐘方向之曲線， 日平均風場無法實際呈現真實路徑，因此會中將進一步以高頻風場驅動積分模式 結果，探討颱風對南海海洋之影響。Item 南海海域之數值模式研究(2004-05-20) 許群; 辛宜佳; 吳朝榮從台灣的南端向西南延伸就到達了東南亞最大的邊緣海----南中國海(South China Sea) ；其為一個半封閉的海盆，北邊由台灣海峽來與東海相連，東北邊 則是由呂宋海峽與西太平洋連接，南邊的麻六甲海峽則與印度洋相連。四週也有 陸地環繞，東邊為呂宋島、東南為巴拉望、南為婆羅州，而西邊是越南、西南為 馬來半島，北邊則為中國的東南沿海。其水深最大可達5000公尺左右，海盆中還 有東沙、中沙與南沙等群島。本研究利用美國普林斯頓大學所發展之三維原始方 程式數值模式--- POM(Princeton Ocean Model) 所建構而成，模式範圍，東西 向從99.degree.E 到124.degree.E，南北向從2.degree.N 到27.degree.N。利用 不同時間、空間尺度的風場資料來驅動，例如: 歐洲中尺度風場中心(ECMWF)的 資料，藉此發現對模式結果所造成的影響。由模式結果發現，南海海盆的表面流 況有季節性的變化。在冬天時因受東北季風的影響，海盆內部的表層環流出現反 時鍾的環流型態(Cyclonic)，並且在呂宋島的西北海域有湧升流(upwalling)的 出現。而在夏天，風向變為西南季風，因此，海盆內出現南北兩個相反的環流系 統；在北半部為反時鍾的環流型態(Cyclonic)，南半部則出現順時鍾的環流型態 (Anticyclonic)，並且在越南東方海域有湧升流的出現。Item Intra-Seasonal Variation in the Velocity Field of the Northeastern South China Sea(2004-05-20) Wu, Chau-Ron; Tang, T. Y.; Lin, S. F.; Yang, Y. J.; Liang, W. D.Two subsurface Acoustic Doppler Current Profilers (ADCP) were deployed at the northeastern South China Sea to study circulation structure in the area as well as the path and process of Kuroshio intrusion. The 48-hour low-pass filtered data reveal significant intra-seasonal variations in the velocity field. The current pattern alternates between clockwise and counterclockwise even within a single month. Local wind forcing dominated by monsoon winds fails to address the phenomena and variations. The present study suggests that wind stress curl forcing is the dominant process controlling the circulation picture in the area. While a stronger wind stress curl appeared and developed off southern tip of Taiwan, it will provide negative vorticity to the intruded current and form an anticyclonic eddy. The stronger current is always going along with the stronger wind stress curl. On the other hand, while the curl in the area looses or decays, the intruded current becomes weakened and forms a cyclonic eddy. The agreement between wind stress curl and the velocity field suggests that changes in the wind stress curl contribute to the intra-seasonal variations in the northeastern South China Sea.Item 台灣週邊海域三維流場資料庫擴建及海洋數值模式研建(I)(2004-05-28) 楊穎堅; 唐存勇; 吳朝榮蒐集、彙整並分析國內現有研究船(海研一、二、三號、水試一號、達觀艦)之船碇式都卜勒流剖儀2003年以前之所有觀測資料、以及國內各單位由國科會所支助在台灣週邊海域所測得之錨碇海流資料，擴建海測局目前海流資料庫之規模；並以此資料庫內容為驗證資料，發展台灣週邊海域度海洋環流、潮流數值模式，提高台灣週邊海域海流預報品質。第一年研究計畫成果，資料庫部分已完成資料蒐集與分析，並且將其提供至海軍海洋測量局，擴建其海洋資料庫之規模。海洋環流模式部分，已完成台灣周圍海域海洋環流粗網格(1/4度)模式之發展，並配合高解析(0.5度*0.5度)的美國國家航空及太空總署的Quick Scatterometer 衛星所測量之海表面風場資料，完成積分。目前正在進行發展細網格(1/10度*1/10度)模式。潮流模式部分，亦已完成粗網格(1/4度)模式之發展與積分，目前也正在進行發展細網格(1/12度*1/12度)模式。模式之驗證部分，目前也已參考海流資料庫所蒐集之歷史資料以及中央氣象局之全國水位資料。模式所的之海流資料(洋流+潮流)，已經開始支援海軍之部分任務，例如操演、救難、搜索等任務。Item 南海之物理-生物耦合模式研究(III)(行政院國家科學委員會, 2004-07-31) 吳朝榮; 劉康克Item 中央氣象局多尺度海流模式之建立(I)(交通部中央氣象局, 2004-12-31) 吳朝榮氣象局的海流/潮汐數值模式需要有較佳的開口邊界條件才能更進一步改進模式結果，現階段符合國際標準的開口邊界條件是要由外圍大尺度模式提供，故須先建構一個大範圍數值模式，然後由這個大範圍模式提供開口邊界條件給較小尺度的氣象局海流/潮汐模式使用。為達成此目標，本研究計畫會建立一個涵蓋整個北太平洋範圍的海流數值模式，並在建構完成後和現有的實測資料以及衛星資料作比較以確定模式之準確性。待測定模式可行後，北太平洋模式將提供開口邊界條件給氣象局現有的中尺度海流/潮汐模式使用，以提高其準確度。進而獲得正確的台灣沿海海流資訊。Item 臺灣周邊海域水文及洋流特徵(臺北市：中華民國海下技術協會, 2005-02-01) 盧鴻復; 吳朝榮在過去的年代中，想要獲得海洋水文或流況的方法，唯有使用測量儀器進行現場觀測一途。但是現場觀測由於受到儀器、技術與天候等等的限制，往往無法同時間對大範圍海域進行水文與海流的觀測。我們利用數個涵蓋不同區域以及具有不同水平解析度的數值模式，針對臺灣周遭海域的水文與流況進行模擬研究。經過與現有的觀測資料驗證比較，成功地重建了臺灣周遭海域的海流與水文環境。這樣的研究成果在我國反潛作戰使用或在其他軍事應用方面皆能提供正確的、有效的海洋戰場環境資訊。本文的主要目的是希望提供臺灣周邊海域水文與流況的模式模擬結果以作為反潛等作戰的參考背景知識。Item A unique seasonal pattern in phytoplankton biomass in low-latitude waters in the South China Sea(2005-04-01) Tseng, C.-M.; G. T. F. Wong; I-I Lin; C.-R. Wu; K.-K. LiuA distinctive seasonal pattern in phytoplankton biomass was observed at the South East Asian Time-series Study (SEATS) station (18°N, 116°E) in the northern South China Sea (SCS). Surface chlorophyll-a, depth-integrated chlorophyll-a and primary production were elevated to 0.3 mg/m3, ∼35 mg/m2 and 300 mg-C/m2/d, respectively, in the winter but stayed low, at ≤0.1 mg/m3, ∼15 mg/m2 and 110 mg-C/m2/d as commonly found in other low latitude waters, in the rest of the year. Concomitantly, soluble reactive phosphate and nitrate+nitrite in the mixed layer also became readily detectable in the winter. The elevation of phytoplankton biomass coincided approximately with the lowest sea surface temperature and the highest wind speed in the year. Only the combined effect of convective overturn by surface cooling and wind-induced mixing could have enhanced vertical mixing sufficiently to make the nutrients in the upper nutricline available for photosynthetic activities and accounted for the higher biomass in the winter.Item 海洋科學教室之七－淺談海嘯(高雄市：海軍軍官雙月刊社, 2005-05-01) 楊穎堅; 吳朝榮; 盧鴻復Item Volume transport through the Taiwan Strait : a numerical study.(the Chinese Geoscience Union, 2005-06-01) Wu, C.-R.; Y.-C. HsinA fine grid resolution model with realistic bathymetry was constructed to study the spatial and temporal structures of flow through the Taiwan Strait where observations are limited. The model covers an expanded domain that includes the entire East China Sea and South China Sea, as well as the region occupied by the Kuroshio. The fine-resolution model derives its open boundary conditions from a larger scale Western Pacific Ocean model. Two numerical weather products from the European Center for Medium-Range Weather Forecasts and National Centers for Environmental Prediction, and one satellite observation-based wind set (QSCAT) are used to force the ocean model. Model experiments suggested that the best simulation is achieved when the model is driven by the QSCAT wind forcing. Several important features are reproduced in the model simulation. The volume transport is northward and largest in summer while minimal volume transport is southward and occurs in fall and winter. The general trend of volume transport is related to the seasonal reversal of monsoon winds. The present model also suggests that flow in the entire Taiwan Strait is to the southwest during periods of strong northeasterly wind. The annual average transport based on the present model is 1.09 Sv (1 Sv = 10 m s 6 3 1 −), which is smaller than most published values based on shipboard Acoustic Doppler Current Profiler (sb-ADCP) observations. The result suggests that sb-ADCP observations are biased toward estimates in summer and fair weather since bad weather during the winter northeast monsoon often prevents seagoing observations.Item 北南海變動研究---子計畫四：南海東北海域之時空變化(行政院國家科學委員會, 2005-07-31) 吳朝榮本項研究計畫將建立一個高解析度的北南海數值模式來研究南海東北海域之時空變化。北南海附近海域的流況相當複雜，除了海底地形變化劇烈外，南海季節性變化的環流系統與台灣海峽海流也同時彙集作用於此海域，另外，黑潮流經呂宋海峽入侵北南海，黑潮流量與路徑皆隨時間改變，這些因素相互作用並造成附近海域流況呈現相當複雜的時空變化。要解釋本海域複雜的海象需要建立一個嚴謹完整且高解析度的數值模式，我們將應用上年度所建立之北太平洋模式(東經99度到西經77度間與南緯20度到南緯60度)輸出結果來提供區域模式之開口邊界條件，且北南海模式將是屬於資料同化數值模式(Data assimilation model)，我們將把衛星測高資料(TOPEX/Poseidon)同化進北南海模式中，以求得較佳的模擬結果，並同時和總計畫中其它子計畫現場觀測所得之資料以及衛星資料等作比較以驗證模式之正確性，並藉由數值模式結果和現場觀測數據間的相互比較分析去對本海域有正確且全面性的瞭解。Item The Interaction of Supertyphoon Maemi (2003) With a Warm Ocean Eddy(American Meteorological Society, 2005-09-01) Lin, I-I; C.-C. Wu; K. A. Emanuel; I.-H. Lee; C.-R. Wu; I.-F. PanUnderstanding the interaction of ocean eddies with tropical cyclones is critical for improving the understanding and prediction of the tropical cyclone intensity change. Here an investigation is presented of the interaction between Supertyphoon Maemi, the most intense tropical cyclone in 2003, and a warm ocean eddy in the western North Pacific. In September 2003, Maemi passed directly over a prominent (700 km 500 km) warm ocean eddy when passing over the 22°N eddy-rich zone in the northwest Pacific Ocean. Analyses of satellite altimetry and the best-track data from the Joint Typhoon Warning Center show that during the 36 h of the Maemi–eddy encounter, Maemi’s intensity (in 1-min sustained wind) shot up from 41 m s 1 to its peak of 77 m s 1. Maemi subsequently devastated the southern Korean peninsula. Based on results from the Coupled Hurricane Intensity Prediction System and satellite microwave sea surface temperature observations, it is suggested that the warm eddies act as an effective insulator between typhoons and the deeper ocean cold water. The typhoon’s self-induced sea surface temperature cooling is suppressed owing to the presence of the thicker upper-ocean mixed layer in the warm eddy, which prevents the deeper cold water from being entrained into the upper-ocean mixed layer. As simulated using the Coupled Hurricane Intensity Prediction System, the incorporation of the eddy information yields an evident improvement on Maemi’s intensity evolution, with its peak intensity increased by one category and maintained at category-5 strength for a longer period (36 h) of time. Without the presence of the warm ocean eddy, the intensification is less rapid. This study can serve as a starting point in the largely speculative and unexplored field of typhoon–warm ocean eddy interaction in the western North Pacific. Given the abundance of ocean eddies and intense typhoons in the western North Pacific, these results highlight the importance of a systematic and in-depth investigation of the interaction between typhoons and western North Pacific eddies.Item Interannual variability of the South China Sea in a data assimilation model(American Geophysical Union (AGU), 2005-09-01) Wu, C.-R.; C.-W. J. ChangSea surface height (SSH) variations in the South China Sea are examined using results from a data assimilation model. After the SSH data have had the annual cycle removed, principal component analysis illustrates two distinct anomaly patterns. The first mode, strongest off Vietnam, would affect the basin-wide gyre intensity. The second mode consists of a meridional dipole feature with a nodal line around 12衹 and is related to the development of the eastward jet and upwelling off Vietnam. Both EOF modes have significant interannual variations and are highly correlated to the ENSO events. The leading phase of mode 2 coefficient provides preliminary evidence for the air-sea interaction and the Pacific-East Asian teleconnection. An innovative mechanism is proposed to describe a weakened upwelling off Luzon in winter 1998. An extra-strong basin-wide warming in summer 1998 persists into fall and winter, preventing the formation of winter upwelling off Luzon in that year.Item 利用遙測估計西北太平洋上層海洋溫度結構(2005-10-19) 林依依; 潘任飛; 吳朝榮