Geoscience Reference
In-Depth Information
monotonically with radius, with a maximum vorticity gradient located at
r
=0
044 (Fig. 2(d)).
Different from the vortex-vortex interaction scenario in Kuo
.
,
2
we focus on the interaction between the asymmetric disturbances and
symmetric core vortex flows. The initial asymmetry specified contains either
a wavenumber 2 or a wavenumber 3 structure in the azimuthal direction.
(To avoid the movement of the core vortex, a wavenumber-one asymmetry
is not considered.) The initial asymmetry is prescribed by a vorticity
perturbation with the following expression:
ς
=5exp
et al.
2
cos(
r − R
p
σ
1
2
−
kλ
)
,
(2.3)
where
r
is the radial distance;
λ
the azimuthal angle;
k
, the azimuthal
wavenumber (
k
=2or
k
= 3) and the radial scale (or size) of the asymmetry
σ
=0
.
025. The radial parameter
R
p
controls the position of the initial
asymmetry.
To investigate how the initial asymmetry position might affect the
formation of the second peak of the symmetric tangential wind, five
experiments have been designed for the wavenumber 2 perturbations. In
the first experiment the initial perturbation is placed at the radius of
0.2 (
R
p
=0
.
2, hereafter denoted as T20, see Fig. 3(a)). In the second
(
a
)
(
b
)
Fig. 3. The initial non-dimensional barotropic asymmetric vorticity with the maximum
center located at the radius of 0.2 for (a) wavenumber 2 case T20 and (b) wavenumber 3
case H20. The contour interval is 1. To obtain vorticity in s
−
1
, multiply by 5
×
10
−
5
.
To obtain radial displacement in km, multiply by 1000. Only the inner 400 km
×
400 km
model domain is shown.
