ATOP -The advanced Taiwan ocean prediction system based on the mpiPOM. Part 1: Model descriptions, analyses and results

A data-assimilated Taiwan Ocean Prediction (ATOP) system is being developed at the National Central University, Taiwan. The model simulates sea-surface height, three-dimensional currents, temperature and salinity and turbulent mixing. The model has options for tracer and particle-tracking algorithms, as well as for wave-induced Stokes drift and wave-enhanced mixing and bottom drag. Two different forecast domains have been tested: a large-grid domain that encompasses the entire North Pacific Ocean at 0.1° × 0.1° horizontal resolution and 41 vertical sigma levels, and a smaller western North Pacific domain which at present also has the same horizontal resolution. In both domains, 25-year spin-up runs from 1988 - 2011 were first conducted, forced by six-hourly Cross-Calibrated Multi-Platform (CCMP) and NCEP reanalysis Global Forecast System (GSF) winds. The results are then used as initial conditions to conduct ocean analyses from January 2012 through February 2012, when updated hindcasts and real-time forecasts begin using the GFS winds. This paper describes the ATOP system and compares the forecast results against satellite altimetry data for assessing model skills. The model results are also shown to compare well with observations of (i) the Kuroshio intrusion in the northern South China Sea, and (ii) subtropical counter current. Review and comparison with other models in the literature of ”(i)” are also given.

[1]  John E. Kutzbach,et al.  Empirical Eigenvectors of Sea-Level Pressure, Surface Temperature and Precipitation Complexes over North America , 1967 .

[2]  A. Ishida,et al.  Can Luzon Strait Transport Play a Role in Conveying the Impact of ENSO to the South China Sea , 2004 .

[3]  Y. Hsueh,et al.  A pressure‐driven South China Sea Warm Current , 2004 .

[4]  L. Oey,et al.  Interannual and seasonal variations of Kuroshio transport east of Taiwan inferred from 29 years of tide‐gauge data , 2011 .

[5]  K. Hanawa,et al.  Subsurface Subtropical Fronts of the North Pacific as Inherent Boundaries in the Ventilated Thermocline , 2002 .

[6]  Dongxiao Wang,et al.  A general circulation model study of the dynamics of the upper ocean circulation of the South China Sea , 2002 .

[7]  A. Ishida,et al.  Seasonal and interannual variations of the North Equatorial Current bifurcation in a high-resolution OGCM , 2004 .

[8]  Ping Chen,et al.  A model simulation of circulation in the northeast Atlantic shelves and seas , 1992 .

[9]  A. Isobe.  Recent advances in ocean-circulation research on the Yellow Sea and East China Sea shelves , 2008 .

[10]  B. Qiu,et al.  Seasonal Eddy Field Modulation of the North Pacific Subtropical Countercurrent : TOPEX / Poseidon Observations and Theory , 1999 .

[11]  George L. Mellor,et al.  A Gulf Stream model and an altimetry assimilation scheme , 1991 .

[12]  George L. Mellor,et al.  The Depth-Dependent Current and Wave Interaction Equations: A Revision , 2008 .

[13]  P. Richardson,et al.  Observations of the Mindanao Current during the western equatorial Pacific Ocean circulation study , 1991 .

[14]  George L. Mellor,et al.  Continuous assimilation of Geosat altimeter data into a three-dimensional primitive equation Gulf Stream model , 1994 .

[15]  S. Chao,et al.  An updated examination of the Luzon Strait transport , 2012 .

[16]  T. Jensen.  Bifurcation of the Pacific North Equatorial Current in a wind-driven model: response to climatological winds , 2011 .

[17]  T. Tang,et al.  Upper-ocean currents around Taiwan , 2003 .

[18]  Gwo-Ching Gong,et al.  Cross-shelf and along-shelf nutrient fluxes derived from flow fields and chemical hydrography observed in the southern East China Sea off northern Taiwan , 2000 .

[19]  Yu-Lin Chang,et al.  Why Are There Upwellings on the Northern Shelf of Taiwan under Northeasterly Winds , 2010 .

[20]  L. Oey,et al.  Typhoon Kai-Tak: An Ocean’s Perfect Storm , 2011 .

[21]  Dong-Kyu Lee,et al.  Observations of Inflow of Philippine Sea Surface Water into the South China Sea through the Luzon Strait , 2004 .

[22]  P. L. Traon,et al.  AN IMPROVED MAPPING METHOD OF MULTISATELLITE ALTIMETER DATA , 1998 .

[23]  Nicolas Reul,et al.  On the limiting aerodynamic roughness of the ocean in very strong winds , 2004 .

[24]  H. Nitani,et al.  Beginning of the Kuroshio , 1972 .

[25]  A. Blumberg,et al.  A Description of a Three‐Dimensional Coastal Ocean Circulation Model , 2013 .

[26]  R. Legeckis.  Long Waves in the Eastern Equatorial Pacific Ocean: A View from a Geostationary Satellite , 1977, Science.

[27]  Yoshiaki Toba,et al.  Local balance in the air-sea boundary processes , 1972 .

[28]  M. Banner,et al.  Modeling Wave-Enhanced Turbulence in the Ocean Surface Layer , 1994 .

[29]  V. Sheremet.  Hysteresis of a Western Boundary Current Leaping across a Gap , 2001 .

[30]  J. Toole,et al.  Observations of the Pacific North Equatorial Current Bifurcation at the Philippine Coast , 1990 .

[31]  J. Bye,et al.  Drag coefficient reduction at very high wind speeds , 2006 .

[32]  Dale B. Haidvogel,et al.  Modeling South China Sea circulation: Response to seasonal forcing regimes , 2006 .

[33]  Kozo H. Yoshida,et al.  A Subtropical Counter-Curreut in the North Pacific:An Eastward Flow Near the Subtropical Convergence , 1967 .

[34]  Lie-Yauw Oey,et al.  Bred-ensemble ocean forecast of loop current and rings , 2007 .

[35]  Jarle Berntsen,et al.  Estimation of the internal pressure gradient in σ-coordinate ocean models: comparison of second-, fourth-, and sixth-order schemes , 2010 .

[36]  Istvan Szunyogh,et al.  Efficient data assimilation for spatiotemporal chaos: A local ensemble transform Kalman filter , 2005, physics/0511236.

[37]  J. Thepaut,et al.  The ERA‐Interim reanalysis: configuration and performance of the data assimilation system , 2011 .

[38]  G. Mellor,et al.  Development of a turbulence closure model for geophysical fluid problems , 1982 .

[39]  Sulagna Ray,et al.  El Niño variability in simple ocean data assimilation (SODA), 1871–2008 , 2011 .

[40]  T. Awaji,et al.  Tidal Exchange through a Strait: A Numerical Experiment Using a Simple Model Basin , 1980 .

[41]  HYBRID DECADE-MEAN GLOBAL SEA LEVEL WITH MESOSCALE RESOLUTION , 2004 .

[42]  M. Powell,et al.  Reduced drag coefficient for high wind speeds in tropical cyclones , 2003, Nature.

[43]  Chun-Chieh Wu,et al.  Upper-Ocean Thermal Structure and the Western North Pacific Category 5 Typhoons. Part I: Ocean Features and the Category 5 Typhoons’ Intensification , 2008 .

[44]  W. Large,et al.  Open Ocean Momentum Flux Measurements in Moderate to Strong Winds , 1981 .

[45]  P. Nielsen.  Coastal Bottom Boundary Layers and Sediment Transport , 1992 .

[46]  A. Weaver,et al.  On the circulation of the North Pcific Ocean: climatology, seasonal cycle and interpentadal variability , 1996 .

[47]  Humio Mitsudera,et al.  Intrusion of the North Pacific waters into the South China Sea , 2000 .

[48]  L. Oey,et al.  Hurricane-induced motions and interaction with ocean currents , 2007 .

[49]  T. Qu,et al.  The Bifurcation of the North Equatorial Current in the Pacific , 2003 .

[50]  Xiaofeng Li,et al.  Observation of hurricane-generated ocean swell refraction at the Gulf Stream north wall with the RADARSAT-1 synthetic aperture radar , 2002, IEEE Trans. Geosci. Remote. Sens..

[51]  Ping Chen,et al.  A nested‐grid ocean model: With application to the simulation of meanders and eddies in the Norwegian Coastal Current , 1992 .

[52]  D. Chelton,et al.  Global observations of nonlinear mesoscale eddies , 2011 .

[53]  I. Ginis,et al.  Effect of surface waves on Charnock coefficient under tropical cyclones , 2004 .

[54]  F. Chai,et al.  Kuroshio intrusion and the circulation in the South China Sea , 2004 .

[55]  Numerical Study of the Upper-Layer Circulation in the South China Sea , 2003 .

[56]  W. Liu,et al.  Warm ocean anomaly, air sea fluxes, and the rapid intensification of tropical cyclone Nargis (2008) , 2009 .

[57]  Huijie Xue,et al.  Oceanic eddy formation and propagation southwest of Taiwan , 2011 .

[58]  Tomoko Inui,et al.  Subtropical Countercurrent in an Idealized Ocean GCM , 1999 .

[59]  W. Hurlin,et al.  Properties of long equatorial waves in models of the seasonal cycle in the tropical Atlantic and Pacific Oceans , 1986 .

[60]  J. Toole,et al.  On the circulation of the upper waters in the western equatorial Pacific Ocean , 1988 .

[61]  R. Flather.  A tidal model of the north-west European continental shelf , 1976 .

[62]  T. Qu,et al.  Upper-Layer Circulation in the South China Sea* , 2000 .

[63]  Yu-Lin Chang,et al.  The Philippines–Taiwan Oscillation: Monsoonlike Interannual Oscillation of the Subtropical–Tropical Western North Pacific Wind System and Its Impact on the Ocean , 2012 .

[64]  Yasumasa Miyazawa,et al.  The Kuroshio onshore intrusion along the shelf break of the East China Sea : The origin of the Tsushima warm current , 2006 .

[65]  198 ON THE THEORY OF OSCILLATORY WAVES , 2022 .

[66]  E. Chassignet,et al.  Seasonal variation of eddy shedding from the Kuroshio intrusion in the Luzon Strait , 2011 .

[67]  Bo Qiu,et al.  Interannual Variability of the North Pacific Subtropical Countercurrent and Its Associated Mesoscale Eddy Field , 2010 .

[68]  Kern E. Kenyon,et al.  Stokes drift for random gravity waves , 1969 .

[69]  O. Madsen,et al.  Combined wave and current interaction with a rough bottom , 1979 .

[70]  L. Oey,et al.  Near-Surface Currents in DeSoto Canyon (1997–99): Comparison of Current Meters, Satellite Observation, and Model Simulation , 2003 .

[71]  W. Pierson,et al.  A proposed spectral form for fully developed wind seas based on the similarity theory of S , 1964 .

[72]  Yu-Lin Chang,et al.  2010 oil spill: trajectory projections based on ensemble drifter analyses , 2011 .

[73]  Takemasa Miyoshi,et al.  Ensemble Kalman Filter and 4D-Var Intercomparison with the Japanese Operational Global Analysis and Prediction System , 2010 .

[74]  H. Kawamura,et al.  Seasonal variation and instability nature of the North Pacific Subtropical Countercurrent and the Hawaiian Lee Countercurrent , 2002 .

[75]  P. Smolarkiewicz.  A Fully Multidimensional Positive Definite Advection Transport Algorithm with Small Implicit Diffusion , 1984 .

[76]  W. White,et al.  Large-scale seasonal and secular variability of the subtropical front in the western North Pacific from 1954 to 1974 , 1978 .

[77]  T. Tang,et al.  Kuroshio in the Luzon Strait , 2008 .

[78]  Kozo H. Yoshida,et al.  A Subtropical Countercurrent (II): A Prediction of Eastward Flows at Lower Subtropical Latitudes@@@亜熱帯低緯度域に存在する東向海流 , 1967 .

[79]  Tal Ezer,et al.  Loop Current warming by Hurricane Wilma , 2006 .

[80]  M. Lavín,et al.  Eddies and Tropical Instability Waves in the eastern tropical Pacific: A review , 2006 .