Ga. Jacobs, SEA-SURFACE HEIGHT VARIATIONS IN THE YELLOW AND EAST CHINA SEAS - 1 -LINEAR-RESPONSE TO LOCAL WIND STRESS, J GEO RES-O, 103(C9), 1998, pp. 18459-18477
The sea surface height (SSH) variations observed by the TOPEX/POSEIDON
satellite in the Yellow and East China Seas are examined over the 3 y
ears from 1993 through 1995 assuming a linear response to wind stress
across the region. The transfer function relating wind stress to SSH i
s modeled by a series of increasingly complex functions that gradually
allow wind stress over successively broader regions and time periods
to influence the SSH solution at a particular point. The SSH response
to instantaneous wind stress at the same point in space implies an Ekm
an transport, but the response explains only a small fraction of the S
SH variability. Relating SSH to wind stress averaged over two subregio
ns and including both instantaneous and 12-hour lagged wind stress ind
icates that a significant portion of SSH variability responds to winds
that are remote in both space and time. An optimal estimation of the
transfer function by minimizing the error variance leads to an extende
d empirical orthogonal function (EEOF) analysis of the wind stress fie
ld. The SSH response to each wind mode is determined. The analysis sho
ws the principle variations in the wind stress to consist of northerly
wind bursts during winter, which produce large SSH drops in the Bohai
Bay and northern Yellow Sea region. The principal wind mode also is s
ignificantly related to variations along the shelf break near the Kuro
shio Current. The third and fourth wind stress modes indicate the pass
age of typhoons.