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 June @ VarSITI 2016 1

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

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

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

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

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

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 SSW Diff. 2008 2009 2010 [Lin et al., 2013 JASTP] 6

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

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

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

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

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

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 SSW effects on ionospheric electron density during 2008-2010 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

Backup – E x B modifications