Magnetized Rossby waves in mid-latitude ionosphere F-layer
We present the results of study of the ionosphere quasi-periodic perturbations on the basis of the analysis of the critical f0F2 frequency variations. The temporal scales of the perturbations are about 7 days and relative amplitude of the f0F2 perturbations are up to 40% of the averaged electron den...
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Головна астрономічна обсерваторія НАН України
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| Цитувати: | Magnetized Rossby waves in mid-latitude ionosphere F-layer / D.A. Saliuk, O. Agapitov, G.P. Milinevsky // Advances in Astronomy and Space Physics. — 2012. — Т. 2., вип. 1. — С. 95-98. — Бібліогр.: 14 назв. — англ. |
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nasplib_isofts_kiev_ua-123456789-1191662025-02-09T13:51:41Z Magnetized Rossby waves in mid-latitude ionosphere F-layer Saliuk, D.A. Agapitov, O. Milinevsky, G.P. We present the results of study of the ionosphere quasi-periodic perturbations on the basis of the analysis of the critical f0F2 frequency variations. The temporal scales of the perturbations are about 7 days and relative amplitude of the f0F2 perturbations are up to 40% of the averaged electron density value. It is assumed from the temporal scale and position that the critical f0F2 frequency variations are caused by Rossby wave-like disturbances with magnetic field influence on the ions. We studied the spatial and temporal scales of the waves at the F-layer altitudes on the basis of the mid-latitude ionosonde network measurements (Millstone Hill, Dyess, and Point Arguello stations data). The generalized Charney-Obukhov equation is proposed to describe the dynamics of the perturbations. We present the numerical model based on the full reduction algorithm for numerical solution of the dynamics equation. 2012 Article Magnetized Rossby waves in mid-latitude ionosphere F-layer / D.A. Saliuk, O. Agapitov, G.P. Milinevsky // Advances in Astronomy and Space Physics. — 2012. — Т. 2., вип. 1. — С. 95-98. — Бібліогр.: 14 назв. — англ. 2227-1481 https://nasplib.isofts.kiev.ua/handle/123456789/119166 en Advances in Astronomy and Space Physics application/pdf Головна астрономічна обсерваторія НАН України |
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We present the results of study of the ionosphere quasi-periodic perturbations on the basis of the analysis of the critical f0F2 frequency variations. The temporal scales of the perturbations are about 7 days and relative amplitude of the f0F2 perturbations are up to 40% of the averaged electron density value. It is assumed from the temporal scale and position that the critical f0F2 frequency variations are caused by Rossby wave-like disturbances with magnetic field influence on the ions. We studied the spatial and temporal scales of the waves at the F-layer altitudes on the basis of the mid-latitude ionosonde network measurements (Millstone Hill, Dyess, and Point Arguello stations data). The generalized Charney-Obukhov equation is proposed to describe the dynamics of the perturbations. We present the numerical model based on the full reduction algorithm for numerical solution of the dynamics equation. |
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Article |
| author |
Saliuk, D.A. Agapitov, O. Milinevsky, G.P. |
| spellingShingle |
Saliuk, D.A. Agapitov, O. Milinevsky, G.P. Magnetized Rossby waves in mid-latitude ionosphere F-layer Advances in Astronomy and Space Physics |
| author_facet |
Saliuk, D.A. Agapitov, O. Milinevsky, G.P. |
| author_sort |
Saliuk, D.A. |
| title |
Magnetized Rossby waves in mid-latitude ionosphere F-layer |
| title_short |
Magnetized Rossby waves in mid-latitude ionosphere F-layer |
| title_full |
Magnetized Rossby waves in mid-latitude ionosphere F-layer |
| title_fullStr |
Magnetized Rossby waves in mid-latitude ionosphere F-layer |
| title_full_unstemmed |
Magnetized Rossby waves in mid-latitude ionosphere F-layer |
| title_sort |
magnetized rossby waves in mid-latitude ionosphere f-layer |
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Головна астрономічна обсерваторія НАН України |
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2012 |
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https://nasplib.isofts.kiev.ua/handle/123456789/119166 |
| citation_txt |
Magnetized Rossby waves in mid-latitude ionosphere F-layer / D.A. Saliuk, O. Agapitov, G.P. Milinevsky // Advances in Astronomy and Space Physics. — 2012. — Т. 2., вип. 1. — С. 95-98. — Бібліогр.: 14 назв. — англ. |
| series |
Advances in Astronomy and Space Physics |
| work_keys_str_mv |
AT saliukda magnetizedrossbywavesinmidlatitudeionosphereflayer AT agapitovo magnetizedrossbywavesinmidlatitudeionosphereflayer AT milinevskygp magnetizedrossbywavesinmidlatitudeionosphereflayer |
| first_indexed |
2025-11-26T11:44:45Z |
| last_indexed |
2025-11-26T11:44:45Z |
| _version_ |
1849853204371603456 |
| fulltext |
Magnetized Rossby waves in mid-latitude ionosphere F-layer
D.A. Saliuk∗, O. Agapitov, G.P. Milinevsky
Advances in Astronomy and Space Physics, 2, 95-98 (2012)
© D.A. Saliuk, O. Agapitov, G.P. Milinevsky, 2012
Taras Shevchenko National University of Kyiv, Glushkova ave., 4, 03127, Kyiv, Ukraine
We present the results of study of the ionosphere quasi-periodic perturbations on the basis of the analysis of the
critical f0F2 frequency variations. The temporal scales of the perturbations are about 7 days and relative amplitude
of the f0F2 perturbations are up to 40% of the averaged electron density value. It is assumed from the temporal
scale and position that the critical f0F2 frequency variations are caused by Rossby wave-like disturbances with
magnetic �eld in�uence on the ions. We studied the spatial and temporal scales of the waves at the F-layer altitudes
on the basis of the mid-latitude ionosonde network measurements (Millstone Hill, Dyess, and Point Arguello stations
data). The generalized Charney-Obukhov equation is proposed to describe the dynamics of the perturbations. We
present the numerical model based on the full reduction algorithm for numerical solution of the dynamics equation.
Key words: plasma waves and instabilities, ionospheric disturbances, wave propagation
introduction
The large-scale wave structures (Rossby waves)
play an important role in energy balance and circu-
lation of the atmosphere and in the oceans. Similar
scale structures are often observed in the ionosphere
as the quasi-periodic disturbances of the electron
density and magnetic �eld variations [1, 6, 11, 12, 14].
We focus on the large-scale zonal ionospheric distur-
bances which propagate at �xed magnetic latitude
[12]. These waves are mainly observed during the
magnetic storms, substorms [5], earthquakes [8, 13]
as well as during man-made explosions [4, 9].
Magnetic �eld ionospheric wave disturbances
(MFIWD) are observed in the F-region of the iono-
sphere at mid-latitudes. They propagate along the
magnetic parallels [8, 12]. Amplitudes of geomag-
netic pulsations can vary from several units to several
tens of nT in these waves. The atmospheric plan-
etary waves are generated in the troposphere and
in the stratosphere. Their penetration into the F-
region is di�cult because of the strong shielding ef-
fect of stable ionospheric zonal winds (especially in
summer) [7], so that the source must exist in the
F-region of the ionosphere. In [7] such source is dis-
cussed to be located in the ionosphere. The funda-
mental factor for the processes of global scale is the
latitudinal inhomogeneity of the geomagnetic �eld,
and MFIWD is a new branch of natural oscillations
of F-layer caused by this mechanism. These distur-
bances manifest themselves in a form of background
oscillations for natural conditions.
The Rossby waves are often observed in the neu-
tral Earth's atmosphere. Usually they are observed
as pressure variations with periods of 2, 5, 10 and
16 days [2]. The seasonal modulation of planetary
waves activity is also observed [3]. Rossby waves
usually propagate westward. But under some condi-
tions the Rossby waves can have stationary nature
(velocity along latitude is almost zero) or even can
be driven to the east. Their appearance is observed
in South Polar Region total ozone data [2]. The
model and physical interpretation of ionosphere pa-
rameters variations (e. g. electron density) remains
among the central problems of the Earth's iono-
sphere study. The critical frequency (f0F2) of F2
ionosphere layer is the mostly reliable measure of a
maximum electron concentration (Nm) in F2 layer
[1]: Nm = 1.24·104(f0F2)2, where f0F2 is expressed
in MHz, Nm in cm−3. Due to the wide application
of ionospheric sounding method a huge amount of
data on seasonal, daily, latitudinal variations of the
electron concentration has been accumulated.
In the present paper we propose the theoretical
model of large-scale atmosphere waves to explain pe-
riodic changes of critical frequency, observed by iono-
spheric sounding.
magnetic field
ionospheric wave disturbances
The analysis of f0F2 variations shows the exis-
tence of the waves with periods about 7 days with rel-
ative amplitude up to 40% of the unperturbed value
∗dima.ubf@gmail.com
95
Advances in Astronomy and Space Physics D.A. Saliuk, O. Agapitov, G. P. Milinevsky
of f0F2. Their behaviour can not be explained by
solar or geomagnetic activity. Taking into account a
temporal scale, time dynamics and theoretical state-
ments, it is possible to assume that f0F2 modi�ca-
tions are stimulated by Rossby-like waves. We anal-
ysed the spatial and temporal properties of planetary
waves at heights of ionospheric F layer on the basis
of wide ionosonde array. The types of the waves have
been de�ned. Numerical model for study of the elec-
tron concentration dynamics in ionosphere F-layer in
the geostrophic approximation is proposed.
Initial equations of planetary electromagnetic
waves in F-region on the equator under the condi-
tion of 2-liquid MHD with mechanical movements
have the following form:
∂~U
∂t
=
1
4πρ0
[[
~∇× ~H
]
× ~H
]
+
+2
[
~U × ~Ω0
]
−
(
~U ~∇~U
)
,
∂ ~H
∂t
= −crot ~E = rot
[
~U × ~H
]
−
− c2
4π
[
~∇×
[
σ̂−1 × rot ~H
]]
,
div~V = 0,
div ~H = 0,
(1)
where ~U and ~V are the velocities along x and y
directions (Fig. 1), ~H = ~H0 − ~h, where ~H0 is
the intensity of the Earth's geomagnetic �eld, ~h -
is the variation of intensity of Planetary Electro-
Magnetic Waves (PEMW), σ̂ is the conductiv-
ity tensor, Ω0 is the planet rotation frequency,
FA = 1
c
[
~j × ~H
]
= 1
4π
[[
~∇× ~H
]
× ~H
]
is the Am-
pere force, rot ~H =
1
c
∂ ~E
∂t
+
4π
c
~j ≈ 4π
c
~j, then ~j ≈
c
4π rot ~H ≡ c
4π
[
~∇× ~H
]
. In the moving coordinate
system ~E = ~E + 1
c
[
~U × ~H
]
, from which one can get:
~j = σ̂
(
~E + 1
c
[
~U × ~H
])
.
The �nal dimensionless output system has the
form:
∂Ω̄z
∂t
− r1
∂ξ̄
∂x̄
− r2H0
∂h̄z
∂x̄
[
∂ξ̄
∂ȳ
∂Ω̄z
∂x̄
− ∂ξ̄
∂x̄
∂Ω̄z
∂ȳ
]
+
+r2
(
H̄0J̄exty + H̄0y
∂J̄extz
∂ȳ
)
,
∂h̄z
∂t
−H0
∂ξ̄
∂x̄
−D
∂2h̄z
∂ȳ2
= (2)
=
(
∂ξ̄
∂ȳ
∂h̄z
∂x̄
− ∂ξ̄
∂x̄
∂h̄z
∂ȳ
)
+ D
∂J̄extx
∂ȳ
,
Ω̄z = −∆⊥ξ̄,
where Ωz =
(
rot~U
)
z
=
∂Uy
∂x
− ∂Uz
∂y
, Ux =
∂ξ
∂y
,
Uy =
∂ξ
∂x
, ξ is the stream function, Jext is
the external current, D =
c2
4πσ⊥
H0
L2
0
t0
H0
=
c2/U2
0
4πσ⊥t0
,
H0 = −2
L0
R
, r1 =
2
R
Ω0t0L0, r2 =
V 2
AL
U0
, U0 = L0
t0
,
L0 = 1000 km, t0 = 100 s.
We used (2) to study numerically the dynamics
of MFIWD with the total reduction algorithm pre-
sented in [10]. The linear approximation gives plan-
etary waves, which propagate along the �xed mag-
netic latitude. In case of taking into account the
nonlinearity the robust vortex solution is present.
experimental study
We analysed the properties of planetary scale
waves propagation of ionosphere F-layer altitude by
use of the critical frequency f0F2 observations. We
used observations from 3 ionospheric stations: Dyess,
Millstone Hill and Point Arguello. Geographic coor-
dinates of the stations are listed in Table 1.
Table 1: Locations of the ionosphere sounding stations.
URSI
Station code Latitude Longitude
Dyess DS932 32.4 260.3
Millstone Hill MHJ45 42.6 288.5
Point Arguello PA836 35.6 239.4
We observde a signi�cant increase of the low-
frequency wave activity during the summer time.
We analysed the manifestations of the low-frequency
wave activity with typical periods of 5�7 days during
May�September 2005. Analysis of the simultaneous
observations by three ionosphere sounding stations
allowed us to estimate the spatial scale of the plan-
etary waves, their wave-vector, and phase velocity.
We estimated the spectral power of the signal by use
of the Morley wavelet and the Blackman-Turkey al-
gorithm.
Fig. 2 (left) shows the F2-layer critical frequency
f0F2 values obtained during May 2005 by use of
the observations on the ionosphere sounding station
Dyess. Spectra of the f0F2 �uctuations are shown in
Fig. 2 (centre). Results of the wavelet transform ap-
plication for these measurements are shown in Fig. 2
(right). Periods obtained for di�erent stations are
4.7�6.2 days (Fig. 3). The phase shift for a signal
�ltered near wave frequency enables the estimation
of spatial scales wave activity. The analysis of the
phase shift shows that the longitudinal wave with
a wave number 2 is observed. A phase velocity is
96
Advances in Astronomy and Space Physics D.A. Saliuk, O. Agapitov, G. P. Milinevsky
Fig. 1: Magnetic dipole coordinate system and the local coordinate system used with the
β-plane approximation.
32.3◦/day, or about 150 km/hour. The wave ampli-
tude can achieve 40% from unperturbed frequency
f0F2.
results and conclusions
We obtained and analysed the system of equa-
tions for the plasma dynamics at the F-layer by use
of β-plane approximation with the magnetic �eld in-
�uence on ions. The generalized Charlie-Obukhov
equation is obtained by use of the geostrophic ap-
proximation with e�ects of the charged particle mo-
tion and electromagnetic forces. We used the con-
servative numerical simulation algorithm based on
the total reduction technique to study the Plane-
tary Electro-Magnetic Waves dynamics at the mid-
dle magnetic latitudes [10]. The considered observed
waves seem to be slow magnetized Rossby-like waves.
The obtained simulation results are veri�ed by
the ionosphere sounding stations measurements of
the f0F2 critical frequency. We present the results
of the analysis of the three ionosphere sounding U.S.
stations: the periods are from 4 to 7 days; the wave-
length is from 0.5 to 1 RE ; perturbation amplitude
is up to 40% of the averaged electron density value.
Wave properties show that the observed variations
can be caused by wave-like disturbances at the F2-
layer altitude similar to Rossby waves in the Earth's
atmosphere but with interaction of charged particle
with magnetic �eld.
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linevsky G.P. 2006, Proc. of the 29th Annual Seminar,
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[3] Agapitov O.V., Grytsai A.V, Saliuk D.A. 2010, Space
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IZMIRAN
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97
Advances in Astronomy and Space Physics D.A. Saliuk, O. Agapitov, G. P. Milinevsky
Fig. 2: Left: dynamics of the critical f0F2 frequency detected during May 2002 by ionosphere sounding at Mill-
stone Hill (shown by dots); solid line shows the value averaged on two days interval. Centre: spectra of the f0F2
�uctuations. Right: wavelet spectra of the f0F2 perturbations (the real part of wavelet transform is shown).
Fig. 3: Signal, �ltered by the period of 5.5 days. a) Point Arguello, b) Dyess and c) Millstone Hill respectively. May
2005
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