Publikationsdatum:
2017-04-04
Beschreibung:
Unstable oscillations confined within the mixed layer close to the
equator are generated
in wind-forced
experiments
performed in a multilevel general
circulation model configured
for the tropical Pacific Ocean. The experiments
indicate that the waves develop preferentially in the eastern Pacific along the
northern temperature front. However, there is clear evidence of a second
unstable
region
along the southern
temperature
front in the central Pacific. In both regions
the instabilities propagate westward, but in the central Pacific their phase speed
is considerably
smaller. The differences
between the wave characteristics
in the
eastern and central Pacific are closely correlated to the differences
in the time
mean conditions of the flow. The eastern instabilities have a structure with two
peaks in amplitude: one located on the equator and the other a few degrees
north
of it. Their dispersion
characteristics
show many similarities to those of tropical
instability
waves
(TIWs) observed
in the Pacific
Ocean,
while the instabilities
which
grow in the central Pacific do not have any known observed
correspondents.
We
explore the spatial variability of the simulated waves through a wavelet analysis,
which provides
detailed results on how the period and wavelength of the instabilities
change
as a function
of longitude,
latitude, and depth. The wavelet
analysis
reveals
that in the eastern Pacific and close to the surface the TIWs have a phase speed
of-48 cm/s, while in the central
Pacific
they have
a phase
speed
of-11 cm/s. In
particular, the change
in the phase
speed
is due to a change
in the dominant period
of the TIWs: The period of the central Pacific instabilities is considerably
longer
than the period of the instabilities present in the eastern Pacific.
Beschreibung:
This work was supported by the Department of Commerce/NOAA grant NA56GP0026. One of the authors (SM) was partially supported by a NASA Global Change Fellowship NGT-30288.
Beschreibung:
Published
Beschreibung:
29613-29635
Beschreibung:
4A. Clima e Oceani
Beschreibung:
JCR Journal
Beschreibung:
restricted
Schlagwort(e):
Ocean modeling
;
Equatorial Ocean
;
Tropical Instability Waves
;
03. Hydrosphere::03.01. General::03.01.01. Analytical and numerical modeling
Repository-Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Materialart:
article
