1. Charles Lin1, Jia-Ting Lin1, Loren Chang2, Yang-Yi Sun2
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 of Earth Science, National Cheng-Kung University, Tainan, Taiwan
2Institute of Space Science, National Central University, Jhung-Li, Taiwan
9 VarSITI 2016 1

2. Effect of the SSW to Equatorial Ionosphere at American sector
COSMIC Ne diff
between SSW DOY 032 and Pre-SSW DOY 009
@ American Longitude for 2009 SSW
[Lin et al., 2012]
Peak of the SSW
On 24-Jan-2009
TEC diff
27-Jan-2009
Mag. Eq.
Ground GPS-TEC observations show dramatic changes shortly after peak of the SSW
Morning enhancement / afternoon reduction
Consistent changes occur in
equatorial vertical drifts
[Goncharenko et al., 2010] 2

3. Effect of the SSW to Equatorial Ionosphere at Asian sector and global
Global COSMIC Ne diff
between SSW DOY 032 and Pre-SSW DOY 009
2009 SSW
Ground-base GPS-TEC observed in Taiwan
2009
N. EIA
[Lin et al., 2013]
These signatures coincide with vertical plasma drift which observed at Jicamarca
[Chau et al., 2010] 3

4. Migrating and nonmigrating tides Stationary planetary waves
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 Time mean
Migrating and nonmigrating tides
COSMIC Obs.
Stationary planetary waves
DE3 (tropospheric origin)
Upward propagation
E-dynamo 4

5. Forming the equatorial daytime peak in TEC
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

6. 2009 SSW:
modifications of the migrating tidal components of the ionospheric Ne
DW1
SW2
TW3
prior
SSW
Phase shifts are very obvious in SW2 components
Σ(DW1+SW2+TW3)
prior
SSW
Diff.
[Lin et al., 2012 GRL] 5

7. Resemblances of the ionospheric/magnetic tides during SSWs of : Modification of migrating tides could explain most of the observed SSW related ionospheric variations in EIA peaks
Σ(DW1+SW2+TW3)
prior
SSW
Diff.
2008
2009
2010
[Lin et al., 2013 JASTP] 6

8. Phase modifications of ionospheric migrating tides
are sensitive to the stratospheric temperature
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
Three distinct phase shifts follow the temperature variation.
2008 SSW
2009 SSW
2010 SSW
DW1 phase
DW1 phase
SW2 phase
SW2 phase
Day of Year, 2008
Day of Year, 2009
Day of Year, 2010 7

9. 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]
Phase shift due to change in vertical wavelength
[Jin et al., 2012] 9

10. Idealized simulations
Quantify the ionospheric responses to the change of amplitude and/or phase in SW2
Lower boundary forcing (~ 97 km)
Control Run
Climatology
DW1 + SW2
(GSWM)
Idealized simulations
in NCAR TIE-GCM
Case 1
Climatology DW1 +
Phase Shifted SW2
(2 hours earlier)
Perpetual 15 January (no calendar advance) - middle winter condition in northern hemisphere
Solar minima and geomagnetic quiet condition - f10.7 = 70 ; POWER = 18 ; CTPOTEN = 30
Case 2
Climatology DW1 +
intensified SW2
Case 3
Climatology DW1 +
intensified SW2 with
2 hour earlier
phase shift 10

11. 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 results in a morning decrease and brief increase in the afternoon
Intensified
SW2 (twice)
Intensified
SW2 (twice)
& phase shift 11

12. Induced TEC variations by different SW2 forcing
Compare with the 2008 SSW
Amplified SW2 with earlier phase shift
SW2
phase increase ?
Only Amplified SW2
No phase shift 12

13. 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

14. Summary
SSW effects on ionospheric electron density during show some resemblances.
The ionospheric equatorial ionization anomaly (EIA) show
a. phase shift of maximum development
b. overall decrease of electron contents during peaked SSW
The phases of ionospheric migrating tidal components are sensitive to the stratospheric temperature (zonal mean atmosphere condition)
Idealized TIE-GCM simulations suggest
in producing the SSW related ionospheric responses
The phase shift of SW2 > the intensification of SW2 amplitude.
Day-to-day variability of SW2 could alter the ionosphere within short time.
progress of the SW2 phase may quite differ in each SSW events 14

15. Backup – E x B modifications