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| Titel |
Hydrodynamic and Thermohaline Seasonal Structures of Peninsular Malaysia's eastern continental shelf sea |
| VerfasserIn |
Farshid Daryabor, Fredolin Tangang, Liew Juneng |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250032184
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| Zusammenfassung |
| The seasonal ocean circulation and the seasonal thermal structure in Peninsular Malaysia’s
eastern continental shelf sea were studied numerically using the Regional Ocean Model
System (ROMS) with 18-km horizontal resolution and 50 sigma levels conforming to a
realistic bottom topography. A 10-year control run was performed using climatological
monthly mean wind stresses, restoring-type surface salt, temp and heat, and observational
oceanic inflow/outflow at the open boundaries. The seasonally averaged effects of isolated
forcing terms are presented and analyzed from the following experiments: 1) heat fluxes
effects removed and 2) wind effects removed. This procedure allowed analysis of the
contribution of individual parameters to the general hydrology and specific features
of the Peninsular Malaysia’s eastern continental shelf sea: for example, coastal
jets, mesoscale topographic gyres, and countercurrents. The results show that the
ROMS model has the capability of simulating seasonal variations of the Peninsular
Malaysia’s eastern continental shelf sea circulation and thermohaline structure. The
simulated Peninsular Malaysia’s eastern continental shelf sea surface circulation
is generally anticyclonic (cyclonic) during the summer (winter) monsoon period
with a strong western boundary current, a mean maximum speed of 0.8 m s-1
(0.5 m s-1), and extending to a depth of around 30 m (40 m). During summer, the
western boundary current splits and partially leaves the coast; the bifurcation point is
at 40-N in Jun and shifts north to 70-N in July. A mesoscale eddy on the Sunda
shelf, the southwest of Natuna Island at (2.50-N, 1060-E) and extending to two
mesoscale eddy at (20-N, 1070-E) and (2.50-N, 1090-E) also on the Gulf of Thailand
(7.50-N, 1040-E), was also simulated. These eddies are cyclonic (anticyclonic) with
maximum swirl velocity of 0.3 m s-1 at the peak of the summer (winter) monsoon.
The simulated thermohaline structure for summer and winter are nearly horizontal
from east to west except at the coastal regions. Coastal upwelling and downwelling
are also simulated: localized lifting (descending) of the isotherms and isohalines
during summer (winter) at the west boundary. The simulation is reasonable when
compared to the observations. Sensitivity experiments were designed to investigate
the driving mechanisms. The Wind is shown to be important to the transport of
baroclinic eddy features, but otherwise insignificant. In general, seasonal circulation
patterns and upwelling phenomena are determined and forced by the wind, while the
heat fluxes plays a secondary role in determining the magnitude of the circulation
velocities. |
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