Oceanography The Official Magazine of
The Oceanography Society
Volume 32 Issue 02

View Issue TOC
Volume 32, No. 2
Pages 150 - 161

Air-Sea-Land Forcing in the Gulf of Tonkin: Assessing Seasonal Variability Using Modern Tools

Peter Rogowski Javier Zavala-GarayKipp ShearmanEric TerrillJohn WilkinTran Hong Lam
Article Abstract

A US–Vietnamese collaborative program established in 2014 provides a framework for partnership with foreign governments. A primary objective of the program is to enhance the Vietnamese collaborators’ skills through training and education and to increase the capacity of their local institutions to conduct research and collect observations that benefit Vietnam. Here, we the synthesize the first results from this program, including development of a high-resolution numerical model and implementation of satellite imagery, high-frequency radar-based surface current measurements, repeat (monthly) coastal hydrography, and drifter and wave observations. We assess seasonal circulation trends along the western Gulf of Tonkin, specifically focusing on the seasonality of a unique Red River water mass that was largely ignored by earlier studies. The development and downcoast advection of the seasonal coastal current was found to be a key dynamical feature of the western region of the gulf. Additionally, observational data sets suggest episodic forcing from storm events is important to the higher frequency dynamics in the region. Collection and subsequent analysis of extensive data sets by this US–Vietnamese partnership confirm the importance of riverine input to Gulf of Tonkin dynamics and address a known scientific gap in previous studies of the region.


Rogowski, P., J. Zavala-Garay, K. Shearman, E. Terrill, J. Wilkin, and T.H. Lam. 2019. Air-sea-land forcing in the Gulf of Tonkin: Assessing seasonal variability using modern tools. Oceanography 32(2):150–161, https://doi.org/10.5670/oceanog.2019.223.

Supplementary Materials

Alford, M.H., R.C. Lien, H. Simmons, J. Klymak, S. Ramp, Y.J. Yang, D. Tang, and M.H. Chang. 2010. Speed and evolution of nonlinear internal waves transiting the South China Sea. Journal of Physical Oceanography 40:1,338–1,355, https://doi.org/​10.1175/2010JPO4388.1.

Binding, C.E., D.G. Bowers, and E.G. Mitchelson-Jacob. 2003. An algorithm for the retrieval of suspended sediment concentrations in the Irish Sea from SeaWiFS ocean colour satellite imagery. International Journal of Remote Sensing 24(19):3,791–3,806, https://doi.org/10.1080/0143116021000024131.

Brakenridge, G.R., and A.J. Kettner. 2017. DFO Flood Event 4518. Dartmouth Flood Observatory, University of Colorado, Boulder, Colorado, USA, https://floodobservatory.colorado.edu/Events/2017Vietnam4518/2017Vietnam4518.html.

Bukata, R.P., J.E. Bruton, and J.H. Jerome. 1983. Use of chromaticity in remote measurements of water quality. Remote Sensing of Environment 13(2):161–177, https://doi.org/​10.1016/0034-4257(83)90020-2.

Cai, S., J. Xie, and J. He. 2012. An overview of internal solitary waves in the South China Sea. Surveys in Geophysics 33(5):927–943, https://doi.org/10.1007/s10712-012-9176-0.

Centurioni, L.R., P.P. Niiler, and D.K. Lee. 2004. Observations of inflow of Philippine Sea surface water into the South China Sea through the Luzon Strait. Journal of Physical Oceanography 34:113–121, https://doi.org/​10.1175/​1520-0485​(2004)034​<0113:OOIOPS>​2.0.CO;2.

Centurioni, L.R., P.N. Niiler, and D.K. Lee. 2009. Near-surface circulation in the South China Sea during the winter monsoon. Geophysical Research Letters 36, L06605, https://doi.org/​10.1029/​2008gl037076.

Chen, C., Z. Lai, R.C. Beardsley, Q. Xu, H. Lin, and N.T. Viet. 2012a. Current separation and upwelling over the southeast shelf of Vietnam in the South China Sea. Journal of Geophysical Research 117, C03033, https://doi.org/10.1029/2011JC007150.

Chen, C., R.L. Limeburner, G. Gao, Q. Xu, J. Qi, P. Xue, Z. Lai, H. Lin, R.C. Beardsley, and B. Owens. 2012b. FVCOM model estimate of the location of Air France 447. Ocean Dynamics 62(6):943–952, https://doi.org/10.1007/s10236-012-0537-5.

Chapman, D.C., and S.J. Lentz. 1994. Trapping of a coastal density front by the bottom boundary layer. Journal of Physical Oceanography 24(7):1,464–1,479, https://doi.org/​10.1175/​1520-0485​(1994)024​<1464:TOACDF>​2.0.CO;2.

Chern, C.S., J. Sen, and J. Wang. 2010. Numerical study of mean flow patterns in the South China Sea and the Luzon Strait. Ocean Dynamics 60:1,047–1,059, https://doi.org/10.1007/s10236-010-0305-3.

Coastal Engineering Research Center. 1984. Shore Protection Manual. US Army Corps of Engineers, Waterways Experiment Station, Vicksburg Mississippi.

Dee, D.P., S.M. Uppala, A.J. Simmons, P. Berrisford, P. Poli, S. Kobayashi, U. Andrae, M.A. Balmaseda, G. Balsamo, P. Bauer, and others. 2011. The ERA-Interim Reanalysis: Configuration and performance of the data assimilation system. Quarterly Journal of the Royal Meteorological Society 137:553–597, https://doi.org/10.1002/qj.828.

de Vries, J.J., J. Waldron, and V. Cunningham. 2003. Field tests of the new Datawell DWR-G GPS wave buoy. Sea Technology 44:50–55.

Ding, Y., C. Chen, R.C. Beardsley, X. Bao, M. Shi, Y. Zhang, Z. Lai, R. Li, H. Lin, and N.T. Viet. 2013. Observational and model studies of the circulation in the Beibu Gulf, South China Sea. Journal of Geophysical Research 118:6,495–6,510, https://doi.org/​10.1002/​2013JC009455.

Fang, G., Y.K. Kwok, K. Yu, and Y. Zhu. 1999. Numerical simulation of principal tidal constituents in the South China Sea, Gulf of Tonkin and Gulf of Thailand. Continental Shelf Research 19:845–869, https://doi.org/10.1016/S0278-4343(99)00002-3.

Figueras, D., A. Karnieli, A. Brenner, and Y.J. Kaufman. 2004. Masking turbid water in the southeastern Mediterranean Sea utilizing the SeaWiFS 510 nm spectral band. International Journal of Remote Sensing 25(19):4,051–4,059, https://doi.org/10.1080/01431160310001657498.

Gao, J., H. Xue, F. Chai, and M. Shi. 2013. Modeling the circulation in the Gulf of Tonkin, South China Sea. Ocean Dynamics 63:979–993, https://doi.org/​10.1007/s10236-013-0636-y.

Gao, J, G. Wu, and H. Ya. 2017. Review of the circulation in the Beibu Gulf, South China Sea. Continental Shelf Research 138:106–119, https://doi.org/10.1016/​j.csr.2017.02.009.

Gan, J.P., H. Li, E.N. Curchitser, and D.B. Haidvogel. 2006. Modeling South China Sea circulation: Response to seasonal forcing regimes. Journal of Geophysical Research 111, C06034, https://doi.org/​10.1029/2005JC003298.

Guan, B., and S. Chen. 1961. Current system in coast of China. Pp. 1–85 in Coast Integration Survey Off China, Reports of Integration Survey in Coast of China. Initial Report 5, Office of the State Science and Technology Commission, Beijing, China.

Guo, C., and X. Chen. 2014. A review of internal solitary wave dynamics in the northern South China Sea. Progress in Oceanography 121:7–23, https://doi.org/10.1016/j.pocean.2013.04.002.

He, C. 1987. Pp. 17–18 in China Encyclopedia: Atmosphere, Oceanography, and Hydrology. Shanghai, China.

Kim, S.Y., E.J. Terrill, and B.D. Cornuelle. 2008. Mapping surface currents from HF radar radial velocity measurements using optimal interpolation. Journal of Geophysical Research 113, C10023, https://doi.org/10.1029/2007JC004244.

Kohut, J.T., H.J. Roarty, and S.M. Glenn. 2006. Characterizing observed environmental variability with HF Doppler radar surface current mappers and acoustic Doppler current profilers: Environmental variability in the coastal ocean. IEEE Journal of Oceanic Engineering 31:876–884, https://doi.org/10.1109/JOE.2006.886095.

Liu, Y.G., R.H. Weisberg, C.R. Merz, S. Lichtenwalner, and G.J. Kirkpatrick. 2010. HF radar performance in a low-energy environment: CODAR seasonde experience on the West Florida Shelf. Journal of Atmospheric and Oceanic Technology 27:1,689–1,710, https://doi.org/​10.1175/​2010JTECHO720.1.

Long, R.B. 1980. The statistical evaluation of directional spectrum estimates derived from pitch/roll buoy data. Journal of Physical Oceanography 10:944–952, https://doi.org/​10.1175/​1520-0485​(1980)010​<0944:TSEODS>​2.0.CO;2.

Manh, D.V., and T. Yanagi. 2000. A study on the residual flow in the in the Gulf of Tongkin. Journal of Oceanography 56:59–68, https://doi.org/​10.1023/​A:1011162524466.

Maritorena, S., O. Hembise Fanton d’Andon, A. Mangin, and D.A. Siegel. 2010. Merged satellite ocean color data products using a bio-optical model: Characteristics, benefits and issues. Remote Sensing of Environment 114:1,791–1,804, https://doi.org/​10.1016/j.rse.2010.04.002.

Mazzini, P.L.F., J.A. Barth, R.K. Shearman, and A. Erofeev. 2014. Buoyancy-driven coastal currents off Oregon during fall and winter. Journal of Physical Oceanography 44:2,854–2,876, https://doi.org/10.1175/JPO-D-14-0012.1.

Mazzini, P.L.F., and R.J. Chant. 2016. Two-dimensional circulation and mixing in the far field of a surface advected river plume. Journal of Geophysical Research 121:3,757–3,776, https://doi.org/​10.1002/2015JC011059.

Nguyen, N.M., P. Marchesiello, F. Lyard, S. Ouillon, G. Cambon, D. Allain, and U.V. Dinh. 2014. Tidal characteristics of the Gulf of Tonkin. Continental Shelf Research 91:37–56, https://doi.org/10.1016/​j.csr.2014.08.003.

Paduan, J.D., and L. Rosenfeld. 1996. Remotely sensed surface current in Monterey Bay from shore-based HF radar (Coastal Ocean Dynamic Application Radar). Journal of Geophysical Research 101:20,669–20,686, https://doi.org/​10.1029/96JC01663.

Ramp, S.R., D.E. Barrick, T. Ito, and M.S. Cook. 2008. Variability of the Kuroshio Current south of Sagami Bay as observed using long-range coastal HF radars. Journal of Geophysical Research 113, C06024, https://doi.org/10.1029/2007JC004132.

Saldías, G.S., R. K. Shearman, J.A. Barth, and N. Tufillaro. 2016. Optics of the offshore Columbia River plume from glider observations and satellite imagery. Journal of Geophysical Research 121:2,367–2,384, https://doi.org/​10.1002/2015JC011431.

Shao, W.Z., Y.X. Sheng, H. Li, J. Shi, Q.Y. Ji, W. Tan, and J.C. Zuo. 2018. Analysis of wave distribution simulated by WAVEWATCH-III model in typhoons passing Beibu Gulf, China. Atmosphere 9:265, https://doi.org/10.3390/atmos9070265.

Shchepetkin, A.F., and J.C. McWilliams. 2005. The Regional Ocean Modeling System (ROMS): A split-explicit, free-surface, topography-​following coordinates ocean model. Ocean Modelling 9(4):347–404, https://doi.org/10.1016/​j.ocemod.2004.08.002.

Simmons, H., M.H. Chang, Y.T. Chang, S.Y. Chao, O. Fringer, C. Jackson, and D. Ko. 2011. Modeling and prediction of internal waves in the South China Sea. Oceanography 24(4):88–99, https://doi.org/​10.5670/oceanog.2011.97.

Sun, H., and W. Huang. 2001. Three-dimensional numerical simulation for tide and tidal current in the Beibu Gulf. Acta Oceanologica Sinica 23(2):1–8.

Tang, C.F., B.W. Tan, and I. Ozturk. 2016. Energy consumption and economic growth in Vietnam. Renewable and Sustainable Energy Reviews 54:1,506–1,514, https://doi.org/10.1016/​j.rser.2015.10.083.

Thomas, A.C., and R.A. Weatherbee. 2006. Satellite-measured temporal variability of the Columbia River plume. Remote Sensing of Environment 100(11):167–178, https://doi.org/​10.1016/j.rse.2005.10.018.

Wyrtki, K. 1961. Physical Oceanography of the Southeast Asian Water. NAGA Report. Vol. 2, Scientific Result of Marine Investigation of the South China Sea and Gulf of Thailand 1959–1961, Scripps Institution of Oceanography, La Jolla, California, 195 pp.

Yankovsky, A.E., and D.C. Chapman. 1997. A simple theory for the fate of buoyant coastal discharges. Journal of Physical Oceanography 27(7):1,386–1,401, https://doi.org/​10.1175/​1520-0485​(1997)027​<1386:ASTFTF>​2.0.CO;2.

Yu, M.G., and J.F. Liu. 1993. South China Sea circulation system and situation. Marine Forecasts 10:13–17 (in Chinese with English abstract).

Zu, T., J. Gan, and S.Y. Erofeeva. 2008. Numerical study of the tide and tidal dynamics in the South China Sea. Deep Sea Research Part I 55:137–154, https://doi.org/10.1016/j.dsr.2007.10.007.