EASNFS
East Asian Seas Nowcast/Forecast System

EASNFS applied for SKII reanalysis is an Ocean Nowcast/Forecast System for the East Asian Seas that was used for real-time prediction at NRL and for a wild variety of studies such as for ITOP and NLIWI. The area of coverage is from 17.3S to 52.2N and from 99.2E to 158.2E. It includes all the Asian Marginal Seas - South China Sea, East China Sea, Yellow Sea and Sea of Japan. The system produces prediction for the sea level variation, 3D ocean current, temperature and salinity.
EASNFS consists an ~1/16 degree, 41-level sigma-z data-assimilating ocean model based on NCOM (Navy Coastal Ocean Model). The horizontal resolution ranges from 9.8 km at Equator to ~6.5 km at northern boundary. The model topography is from 2-min NRL DBDB2 bathymetry data base and improved with available high resolution bathymetry and sounding data. There are 142 rivers or fresh water runoff points with monthly discharges in the EASNFS.
For reanalysis the system is initialized at 1997/12/01 from temperature/salinity analyses based on satellite altimeter SSH and MCSST and climatology. Once model is initialized it continuously assimilates the synthetic temperature/salinity profiles generated by a data analysis model called MODAS to produce reanalysis. A vertical weighting function and scale speration scheme are applied for the data assimilation. Satellite altimeter (GFO, Jason-1, ERS-2, EnviSat and TOPEX) sea surface height anomaly and AVHRR sea surface temperature (MCSST) are used.
Three hourly surface heat fluxes, solar radiation, wind stresses and sea level air pressure from NOGAPS/FNMOC are applied for surface forcing. The open boundary conditions including sea surface elevation, transport, temperature, salinity and currents are provided by the NRL Global NCOM. An one way coupling scheme is used to ingest those boundary conditions into the EASNFS model.
EASNFS realaysis was produced over a 15-year period from 1998 to 2012. It was used to study mainly the typhoon-ocean interaction but also provided open boundary conditions to embbeded high-resolution grids, mostly for internal waves studies in the northern South China Sea.

Applications of EASNFS & embbeded high resolution grids

Chen, C.-C., D.S. Ko, G.-C. Gong, C.-C. Lien, W.-C. CHou, H.-J. Lee, F.-K. Shiah, and Y.-S. W. Huang, 2022: Reoxygenation of the hypoxia in the East China Sea: A ventilation opening for marine life, Front. Mar. Sci. 8, 787808, doi:10.3389/fmars.2021.787808
Le Boyer, A., M.H. Alford, R. Pinkel, T.D. Hennon, Y.J. Yang, D.S. Ko, and J. Nash, 2019: Frequency shifts of near inertial waves in the South China Sea, J. Phys. Oceanogr., 50, 1121-1135, doi:10.1175/JPO-D-19-0103.1
Lee, I-H., T.-Y. Fan, D.S. Ko, and K.-H. Fu, 2018: The temporal variations of daily tempearture in coral reef area of Nanwan Bay, Sci. Rep., 10, 8656, https://doi.org/10.1038/s41598-020-65194-8
Rogers, J.S., M.D. Rayson, D.S. Ko, K.B. Winters, O.B. Fringer, 2018: A framework for seamless one-way nesting of internal wave-resolving ocean models, Ocean Modelling, 143, 101462, doi:10.1061/j.ocemod.2019.101462
Ko, D.S., S.-Y. Chao, C.-C. Wu, I-I Lin, and S. Jan, 2016: Impacts of Typhoon Fanapi (2010) on Seas around Taiwan, Terr. Atmos. Ocean. Sci., 27, 261-280, doi:10.3319/TAO.2015.10.28.01(Oc)
Wu, C.-C., W.-T. Tu, I.-F. Pun, I-I Lin, and M.S. Peng, 2016: Tropical cyclone-ocean interaction in Typhoon Megi (2010). A synergy study based on ITOP observations and atmosphere-ocean coupled model simulations, J. Geophys. Res. Atmos., 121, 153-167, doi:10.1002/2015JD024198
Pickering, A., M. Alford, J. Nash, L. Rainville, M. Buijsman, D.S. Ko, and B. Lim, 2015: Structure and variability of internal tides in Luzon Strait, J. Phys. Oceanogr., 45, 1574-1594, doi:10.1175/JPO-D-14-0250.1
Warn-Varnas, A., D.S. Ko, and A. Gangopadhyay, 2015: Signatures of tidal interference patterns in South China Sea, J. Oceanogr., 71, 251-262, doi:10.1007/s10872-015-0282-8
Ko, D.S., S.-Y. Chao, C.-C. Wu, and I-I Lin, 2014: Impacts of Typhoon Megi (2010) on the South China Sea, J. Geophys. Res. Oceans, 119, 4474-4489, doi:10.1002/2013JC009785
Chen, Y.-J., D.S. Ko, and P.-T. Shaw, 2013: The generation and propagation of internal solitary waves in the South China Sea, J. Geophys. Res. Oceans, 118, 6578-6589, doi:10.1002/2013JC009319
Lee, I.-H., D.S. Ko, Y.-H. Wang, L. Centurioni, and D.-P. Wang, 2013: The mesoscale eddies and Kuroshio transport in the western North Pacific east of Taiwan from 8-year (2003-2010) model reanalysis, Ocean Dynamics, 63, 1027-1040, doi:10.1007/s10236-013-0643-z
Ma, B.B., R.-C. Lien, and D.S. Ko, 2013: The variability of internal tide in the northern South China Sea, J. Oceanogr., 69, 619-630, doi:10.1007/s10872-013-0198-0
Lin, I-I, C. Hu, Y.-H. Li, T.-Y. Ho, T. Fischer, G.T.F. Wong, J. Wu, C.-W. Huang, D.A. Chu, D.S. Ko, and J.-P. Chen, 2011: Fertilisation potential of volcanic dust in the low nutrient low chlorophyll western North Pacific Subtropical Gyre - satellite evidence and laboratory study, Global Biogeochem. Cycles, doi:10.1029/2009GB003758
Simmons, H., M.-H. Chang, Y.-T. Chang, S.-Y. Chao, O. Fringer, C.R. Jackson, and D.S. Ko, 2011: Modeling and prediction of internal waves in the South China Sea, Oceanography, 24, 88-99, http://dx.doi.org/10.5670/oceanog.2011.97
Chang, Y.-T., T.Y. Tang, S.-Y. Chao, M.-H. Chang, D.S. Ko, Y.J. Yang, W.-D. Liang, and M.J. McPhaden, 2010: Mooring observations and numerical modeling of thermal structures in the South China Sea, J. Geophys. Res. Oceans, doi:10.1029/2010JC006293
Qian H., P.-T. Shaw, and D.S. Ko, 2010: Generation of internal waves by barotropic tidal flow over a steep ridge, Deep-Sea Res. I, 57, 1521-1531, doi:10.1016/j.dsr.2010.09.001
Ko, D.S., S.-Y. Chao, P. Huang, and S.F. Lin, 2009: Anomalous upwelling in Nan Wan: July 2008, Terr. Atmos. Ocean. Sci., 20, 839-852, doi:10.3319/TAO.2008.11.25.01(Oc)
Ko, D.S., P. Martin, S.-Y. Chao, P.-T. Shaw, and R.C. Lien, 2009: Internal Waves at South China Sea, NRL Review, 2008, 183-186.
Chao, S.-Y., D.S. Ko, R.C. Lien, and P.T. Shaw, 2007: Assessing the west ridge of Luzon Strait as an internal wave mediator, J. Oceanogr., 63, 897-911, doi:10.1007/s10872-007-0076-8
Teague, W.J., D.S. Ko, G.A. Jacobs, H.T. Perkins, J.W. Book, S.R. Smith, K.-I. Chang, M.-S. Suk, K. Kim, S.J. Lyu, and T.Y. Tang, 2006: Currents across the Korea/Tsushima strait: review of LINKS observations, Oceanography, 19, 53-65.
Keen, T.R., D.S. Ko, R.L. Slingerl, and S. Riedlinger, 2006: Potential transport pathways of terrigenous material in the Gulf of Papua, Geophys. Res. Lett., 33, L04608, doi:10.1029/2005GL025416

Reanalyses: SSH | SST | SSS | TWe | TWt | TWs         5day-average ssh: WPac 1998 | 2005 | 2012

Drifter Tracking
2012 | 2011 | 2010 | 2009 | 2008 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 | 1999 | 1998 | 15yrs

Tides: Yellow/East China Sea | Tsientang River | Taiwan Strait

East China Sea (2014): SST | SSS

Transport through Taiwan Strait | Tidal Prediction

Internal Tidal Energy at South China Sea: movie

Internal Waves at Lombok Strait from a high-resolution model nested in EASNFS: movie

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