AOSWA Workshop

Cause and Effect ofSep. 12-13, 2014 geomagnetic storm
K.-S. Cho1, R.-S. Kim1, S.-J. Kim1, J.-A. Hwang1,Y.-S. Kwak1, S.-H. Park2, P. Kumar1 and S.-J. Jang1,31Korea Astronomy and Space Science Institute2National Observatory of Athens, Greece
3Kyunghee University, Korea

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Geomagnetic Storms during Sep. 12-13, 2014
 Two Geomagnetic Storms• 09/11 23h UT : Kp=5, Dst = -20 nT• 09/12 21h UT : Kp=7, Dst=-75 nT

 2 strong flares• 09/08 23:12 M4.6 (N14E31)• 09/10 17:21 X1.6 (N11E05)
 Proton event• 09/11 02:40 126 pfu(N16W06,2

1. KASI Prediction and Service
Solar and Space weather group3

2014 Sep. 11, 02:16 UT, Report from KASI

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2014 Sep. 11, 02:16 UT, Report from KASI

Report from RRA

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Real-time simulation of RB

VERB provided by UCLA

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North Polar Route monitoring

Proton Flux

HF attenuation @ 8.83

2. Effects
Solar and Space weather group9 ICME’s arrival
 1st : 09/11 ~23h UT
 2nd: 09/12 ~ 16h UT
 Bz during two ICMEs looks positive (N) 2 Geomagnetic Storms• 09/11 23h UT : Kp=5, Dst = -20 nT• 09/12 21h UT : Kp=6, Dst=-75 nT
10Ground observation at BOH (L = 1.35)
Fluxgate and Mageto-Impedence magnetometer

1st Shock
09/11
23UT

2nd Shock
09/12
16UT

Pi2 Pulsations (6-25 mHz)observed after the shocks

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Multipoint observations in themagnetosphereYX

GSE X-Y plane12

9/11 (KST)

9/13 (KST)
9/12 (KST)Space weather data

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RBSP/MagEIS observation

Science data
Science data
Drop outs

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NOAA POES observationelectronproton
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Global Thermosphere/Ionosphere

Strom Time
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KASI VHF ionosphere observations
E region

40.8MHz, KAF, CSR

F region173. Cause
Solar and Space weather group18

Empirical model for forecast ofge oe ffe c tive CMEs us ing Sola r Da ta
 Empirical storm prediction model (Kim et al., 2010, JGR) We derived the empirical storm prediction formulas by using CME parameters.
 Direction parameter has the best correlation with the storm strength.
 Since the source locations of geoeffective CMEs are asymmetrical inlongitude, we consider West 15° offset.
 We divide CMEs into two groups according to their magnetic fieldorientation.

 Forecast Evaluation
 Model prediction gives us the PODy, PODn, FAR, and CSI as 0.93, 0.50, 0.26,
and 0.70, respectively.

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Web-based empirical Model• Inputs– CME time, AW, and F/B– CME source location, magnetic field orientation– CME propagation speed and direction (D)• Outputs (forecast)– Storm time and Storm strength (Dst)– Probability of storm

20 CME speed: CMEs during Sep. 8~11, 2014
 LASCO/C2, C3 and CME lists• Cactus

From Cactus: 2014/09/09 CME speed ~ 900 km/s
: 2014/09/10 CME speed ~ 1600 km/s

 2 strong flares• 09/08 23:12 M4.6 (N14E31)• 09/10 17:21 X1.6 (N11E05)

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 Source Location and Magnetic field direction (AR 12158): HMI magnetogram and AIA 304

Strong chromospheric emission(near footpoint)- Eastern part of active region

 Southward -direction22



Geomagnetic Storm Forecasts (M4.6 flare) 2014/09/09 00:16 CME• V ~ 900 km/s
• D=0.49

 Forecast• Expected arrival: 09/11 05 ~ 11h UT• Expected Dst = -64 nT (if N=-46nT)• Arrival: 09/11 ~ 23h UT• Dst = -20nT

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

Geomagnetic Storm Forecasts (X1.6 flare) 2014/09/10 17:36 CME• V ~ 1600 km/s
• D = 0.65

 Forecast• Expected arrival: 09/12 11~17h UT• Expected Dst = -174 nT (if N=-104nT)• Minor Storm: 09/12, 16h UT• Dst= -75 nT

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Two CMEs (?) erupted by the X1.6 flare

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128 km/s

328 km/s

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Magnetic field in the source region (AR 12158)
2014/09/09 00:00 UT

2014/09/10 00:00 UT

2014/09/11 00:00 UT

R1
R2

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Helicity Injection through the Local Regions
M4.6

R1

X1.6

R2

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Estimation of Field Line Direction from Helicity
Left-handed

Left-handed

Sheared Field
Potential Field
Solar windNorthward Bz
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

Geomagnetic Storm Forecasts
 2014/09/10 17:36 CME• V ~ 1100 km/s
• D = 0.81
• M = North

 Forecast• Expected arrival: 09/12 11 ~ 09/13 00h UT• Expected Dst = -127nT• Storm: 09/12 ~ 16h UT• Dst=-75 nT (13 0h)1000 km/s

1100 km/s
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Summary• Cause- There were two geomagnetic storms on Sep. 11th andSep. 12th , 2014.
- The first weak storm was driven by the CME related toM4.6 flare and the second minor storms was driven by oneof the CMEs related to X1.6 flare.
- The second storm was not strong because it was causedby the fast CME originated from the eastern part of the AR
12158 with northward magnetic field.

• Effect- Electron flux in radiation belt increases in low energy
channel while decreases in High energy channel (VAPobservation)- Electron and proton precipitation were observed by
POES satellite- TEC and O/N2 show a decrease in the polar region.
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Thank youwww.kasi.re.kr

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