Interannual variability of the surface summertime eastward jet in the South China Sea
Wilkin, John L.
Zhang, Weifeng G.
Arango, Hernan G.
Levin, Julia C.
Castruccio, Frederic S.
MetadataShow full item record
The summertime eastward jet (SEJ) located around 12°N, 110°E–113°E, as the offshore extension of the Vietnam coastal current, is an important feature of the South China Sea (SCS) surface circulation in boreal summer. Analysis of satellite-derived sea level and sea surface wind data during 1992–2012 reveals pronounced interannual variations in its surface strength (SSEJ) and latitudinal position (YSEJ). In most of these years, the JAS (July, August, and September)-mean SSEJ fluctuates between 0.17 and 0.55 m s−1, while YSEJ shifts between 10.7°N and 14.3°N. These variations of the SEJ are predominantly contributed from the geostrophic current component that is linked to a meridional dipole pattern of sea level variations. This sea level dipole pattern is primarily induced by local wind changes within the SCS associated with the El Niño-Southern Oscillation (ENSO). Enhanced (weakened) southwest monsoon at the developing (decaying) stage of an El Niño event causes a stronger (weaker) SEJ located south (north) of its mean position. Remote wind forcing from the tropical Pacific can also affect the sea level in the SCS via energy transmission through the Philippine archipelago, but its effect on the SEJ is small. The impact of the oceanic internal variability, such as eddy-current interaction, is assessed using an ocean general circulation model (OGCM). Such impact can lead to considerable year-to-year changes of sea level and the SEJ, equivalent to ∼20% of the observed variation. This implies the complexity and prediction difficulty of the upper ocean circulation in this region.
Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 119 (2014): 7205–7228, doi:10.1002/2014JC010206.
Showing items related by title, author, creator and subject.
Enhanced acoustic mode coupling resulting from an internal solitary wave approaching the shelfbreak in the South China Sea Chiu, Linus Y. S.; Reeder, D. Benjamin; Chang, Yuan-Ying; Chen, Chi-Fang; Chiu, Ching-Sang; Lynch, James F. (Acoustical Society of America, 2013-03)Internal waves and bathymetric variation create time- and space-dependent alterations in the ocean acoustic waveguide, and cause subsequent coupling of acoustic energy between propagating normal modes. In this paper, the ...
Seasonal changes in gaseous elemental mercury in relation to monsoon cycling over the northern South China Sea Tseng, Chun-Mao; Liu, Char-Shine; Lamborg, Carl H. (Copernicus Publications on behalf of the European Geosciences Union, 2012-08-16)The distribution of gaseous elemental mercury (GEM) was determined in the surface atmosphere of the northern South China Sea (SCS) during 12 SEATS cruises between May 2003 and December 2005. The sampling and analysis of ...
St. Laurent, Louis C.; Simmons, Harper L.; Tang, Tswen Yung; Wang, YuHuai (The Oceanography Society, 2011-12)Luzon Strait and South China Sea waters are among the most energetic internal wave environments in the global ocean. Strong tides and stratification in Luzon Strait give rise to internal waves that propagate west into the ...