Ionosphere Responses to
Sudden Stratosphere Warming (SSW) :
Multiple years
observations from FORMOSAT-3/COSMIC
and TIE-GCM simulations
Charles Lin1, Jia-Ting Lin1, Loren Chang2, Yang-Yi Sun2
1Department
2Institute
9 June @ VarSITI 2016
of Earth Science, National Cheng-Kung University, Tainan, Taiwan
of Space Science, National Central University, Jhung-Li, Taiwan
1
Effect of the SSW to Equatorial Ionosphere at American sector
Peak of the SSW
On 24-Jan-2009
TEC diff
27-Jan-2009
COSMIC Ne diff
between SSW DOY 032 and Pre-SSW DOY 009
@ American Longitude for 2009 SSW
[Lin et al., 2012]
Mag. Eq.
Ground GPS-TEC observations
show dramatic changes
shortly after peak of the SSW
Morning enhancement / afternoon reduction
[Goncharenko et al., 2010]
Consistent changes occur in
equatorial vertical drifts
2
Effect of the SSW to Equatorial Ionosphere at Asian sector and global
Ground-base GPS-TEC observed in Taiwan
Global COSMIC Ne diff
between SSW DOY 032 and Pre-SSW DOY 009
2009 SSW
2009
[Lin et al., 2013]
These signatures coincide with vertical plasma
drift which observed at Jicamarca
[Chau et al., 2010]
3
Ionospheric Ne/TEC tidal signatures have been treated as the proxies of
neutral atmosphere tides
Method for extracting tides and waves from the F3/C electron density
Zonal
and
COSMIC Time mean
Obs.
Migrating and nonmigrating tides
Stationary planetary waves
DE3 (tropospheric origin)
Upward propagation
E-dynamo
4
Physical Interpretations of Ionospheric Tides
[Chang et al., 2013]
DW1
 Forming the equatorial daytime peak in TEC
 Still could be modified by tidal forcing from below
SW2
 The strength of EIA crests
 Influenced strongly by the MLT SW2 forcing
TW3
 TEC trough/dip between the EIA crests
8
2009 SSW:
modifications of the migrating tidal components of the ionospheric Ne
prior
DW1
SW2
TW3
SSW
Phase shifts are very obvious in SW2 components
Σ(DW1+SW2+TW3)
prior
SSW
Diff.
[Lin et al., 2012 GRL]
5
Resemblances of the ionospheric/magnetic tides during SSWs of 2008-2010:
Modification of migrating tides could explain most of the observed SSW related ionospheric
variations in EIA peaks
Σ(DW1+SW2+TW3)
prior
2008
2009
2010
SSW
Diff.
[Lin et al., 2013 JASTP]
6
Phase modifications of ionospheric migrating tides
are sensitive to the stratospheric temperature
• Three distinct phase shifts
follow the temperature
variation.
DW1 phase
2008 SSW
• The phase shifts appear good relationship
with stratospheric temperature
• Earlier phase shift of DW1 are seen in all latitude
• Earlier phase shift of SW2 and TW3 are seen in EIA
2009 SSW
2010 SSW
Day of Year, 2009
Day of Year, 2010
DW1 phase
SW2 phase
SW2 phase
Day of Year, 2008
7
Significant variability occurs in the SW2 in MLT region due to the
influence of the zonal mean atmosphere on tidal propagation
peak warming of 2009 SSW
In an average SSW events,
The change in SW2 Amplitude and Phase
can generate temporal plasma drift
variability similar to the observations
[Pedatella et al., 2013]
[Jin et al., 2012]
Phase shift due to
change in vertical wavelength
9
Quantify the ionospheric responses to the change of
amplitude and/or phase in SW2
Lower boundary forcing
(~ 97 km)
Control Run
Idealized simulations
in NCAR TIE-GCM
Climatology
DW1 + SW2
(GSWM)
Case 1
Climatology DW1 +
Phase Shifted SW2
(2 hours earlier)
Perpetual 15 January (no calendar advance)
- middle winter condition in northern hemisphere
Case 2
Climatology DW1 +
intensified SW2
Solar minima and geomagnetic quiet condition
- f10.7 = 70 ; POWER = 18 ; CTPOTEN = 30
Case 3
Climatology DW1 +
intensified SW2 with
2 hour earlier
phase shift 10
Induced TEC variations by different SW2 forcing
2 days after activated
Control
run
Phase shift in SW2 only can produce
a morning enhancement followed by
Afternoon reduction of TEC
SW2 Phase
Shift (2 hrs.
earlier)
Standalone intensification of SW2 amplitude
Intensified
results in a morning decrease and SW2 (twice)
brief increase in the afternoon
Intensified
SW2 (twice)
& phase shift
11
Induced TEC variations by different SW2 forcing
Compare with the 2008 SSW
SW2
phase
increase ?
12
Induced TEC variations by different SW2 forcing
20 days after activated
Integrated [O/N2] ratio
Tidal mixing effect also plays a role to reduce the
Ionospheric density during the daytime
13
Summary
1.
SSW effects on ionospheric electron density during 2008-2010 show some
resemblances.
2.
The ionospheric equatorial ionization anomaly (EIA) show
a. phase shift of maximum development
b. overall decrease of electron contents during peaked SSW
3.
The phases of ionospheric migrating tidal components are sensitive to the
stratospheric temperature (zonal mean atmosphere condition)
1.
Idealized TIE-GCM simulations suggest
in producing the SSW related ionospheric responses
a.
The phase shift of SW2 > the intensification of SW2 amplitude.
b. Day-to-day variability of SW2 could alter the ionosphere within short
time.
c. progress of the SW2 phase may quite differ in each SSW events
14
Backup – E x B modifications
LT
Control Run : Zonal Mean ExB at mag. eq and 300 km
21 (a)
18
15
12
9
6
3
0
-2
0
ExB [m/s]
25
MAX : +15.8 m/s
MAX : +15.8 m/s
LT : 13.0
LT : 13.0
2
4
6
8
10
20
12
14
16
18
15
SW2 Phase Shift : (diff) Zonal Mean ExB at mag. eq and 300 km ExB
21 (b)
18
15
12
9
6
3
0
-2
0
10
MAX : +18.6 m/s
MAX : +18.8 m/s
LT : 11.7
LT : 11.7
2
4
6
8
10
LT
LT
SW2 Phase Shift : Zonal Mean ExB at mag. eq and 300 km
5
12
14
16
18
0
Twice SW2 : Zonal Mean ExB at mag. eq and 300 km
MAX : +18.5 m/s
LT : 13.7
LT : 13.0
-5
LT
MAX : +21.4 m/s
-10
0
2
4
6
8
10
12
14
16
18
2
4
6
8
10
12
14
16
18
5
21 (d)
18
15
12
9
6
3
0
-2
0
-15
MAX : +25.1 m/s
MAX : +22.8 m/s
LT : 11.7
LT : 11.0
2
4
6
8
10
Model Days
12
14
-20
16
18
18
15
12
9
6
3
0
-2
0
0
2
4
6
8
10
12
14
16
18
-5
Twice SW2 & Phase Shift : (diff) Zonal Mean ExB at mag. eq and 300 km
-25
LT
LT
10
21 (f)
Twice SW2 & Phase Shift : Zonal Mean ExB at mag. eq and 300 km
LT
15
Twice SW2 : (diff) Zonal Mean ExB at mag. eq and 300 km
21 (c)
18
15
12
9
6
3
0
-2
21 (e)
18
15
12
9
6
3
0
-2
0
21 (g)
18
15
12
9
6
3
0
-2
0
-10
2
4
6
8
10
Model Days
12
14
16
18
-15