TITLE:
Regional Sea Level Variation on Interannual Timescale in the East China Sea
AUTHORS:
Shouwen Zhang, Ling Du, Hui Wang, Hua Jiang
KEYWORDS:
ECS Sea Level, Interannual Variation, Wind Field, Ocean Current, Steric Effect
JOURNAL NAME:
International Journal of Geosciences,
Vol.5 No.12,
November
14,
2014
ABSTRACT: Interannual
sea level variation is investigated with the oceanic and atmospheric datasets
in the East China Sea (ECS). Two modes are distinct on the interannual
timescale, illustrated as the basin mode and the dipole mode. They account for 20%
and 18% to the total interannual sea level variance respectively. The basin
mode corresponds to the variability of the Kuroshio transport which is
modulated by the PDO while the dipole mode is likely related to the local
oceanic and atmospheric adjustment. Large-scale atmospheric circulation effect
is dominant in influencing the interannual sea level in the ECS. ECS sea level
responds barotropically to the basin-wide wind field, which illustrates
negative correlation to the zonal-mean wind stress curl in the Pacific Ocean. Sea
level variation exhibits the negative correlation at 8 years lag with the basin
mean wind stress curl anomalies on the interannual timescale. The lagging years
are consistent with the timescale that the baroclinic Rossby waves propagate westward
in the North Pacific Ocean. Wind stress curl anomalies could also change the
strength of the Kuroshio transport, and thus affect the local sea level through
sea surface height adjustment. Local oceanic and atmospheric effect illustrates
as another influence process. Steric effect contributes more than 20% to the
interannual sea level gradually in a belt from the Fujian and Zhejiang coasts
to the Korea/Tsushima strait. Especially in the northeast part, its
contribution could be up to 60%. While for the local atmospheric process, zonal
wind acts as a more important role on sea level than meridional component.