How the Intensity of Geomagnetic Storms can be Determined from Solar Data
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How the Intensity of Geomagnetic Storms can be Determined from Solar Data How the Intensity of Geomagnetic Storms can be Determined from Solar Data Coronal Mass Ejections (CMEs) are correlated with geomagnetic storms, which are a response of Coronal Mass Ejections (CMEs) are correlated with geomagnetic storms, which are a response of the magnetosphere to an action of the southward interplanetary magnetic field (IMF). We the magnetosphere to an action of the southward interplanetary magnetic field (IMF). We discuss a new method to produce forecast of the intensity of a geomagnetic storm at least 1 discuss a new method to produce forecast of the intensity of a geomagnetic storm at least 1 day in advance based solar data. day in advance based solar data. Vasyl Yurchyshyn, Big Bear Solar Observatory, 40386 North Shore Lane, Big Bear City, CA 92314, [email protected] Vasyl Yurchyshyn, Big Bear Solar Observatory, 40386 North Shore Lane, Big Bear City, CA 92314, [email protected] 1. We found that the CME projection 1. We found that the CME projection speed is related to the Bz in IMF : speed is related to the Bz in IMF : Fig. 1 Fig. 1 The hourly averaged Bz measured at The hourly averaged Bz measured at the front of an ejecta (ACE, GSM) vs the front of an ejecta (ACE, GSM) vs the projected speed of CMEs. The solid the projected speed of CMEs. The solid line is an exponential fit: line is an exponential fit: F1=Bz[nT]=12.3+0.7exp(V/404). F1=Bz[nT]=12.3+0.7exp(V/404). The dashed The dashed lines show r.m.s=7nT. lines show r.m.s=7nT. 2. In turn, the Bz in IMF defines the 2. In turn, the Bz in IMF defines the intensity (the Dst Index) of a storm intensity (the Dst Index) of a storm Fig. 2 Fig. 2 The Dst index vs the hourly averaged The Dst index vs the hourly averaged Bz. The solid line is a 3 Bz. The solid line is a 3 rd rd degree degree polinominal fit, polinominal fit, F2 F2, and the dashed lines , and the dashed lines show r.m.s=33nT show r.m.s=33nT. The X4.5/3B flare at 18:46UT on March 10, 1989 produced 1 st CME, which arrived on March 13 at 02:00UT. Its travel speed was about 760km/s, while the initial speed was 1000km/s. Bz predicted: -10 … -24 nT Dst predicted: -100 … -180 nT The X1.0/2B flare on March 11 at 15:33UT produced 2 nd CME, which arrived on March 13 at 10:00UT. Its travel speed was about 990km/s, while the initial speed was 1100km/s. Bz predicted: -13 … -27 nT Dst predicted: (-120 … -190)+ΔDst 1 = -210…-280 ΔDst 1 ΔDst 2 The M6.7/1n flare on March 12 at 08:16UT produced 3 rd CME, which arrived on March 14 at 19:00UT. Its travel speed was about 1200km/s, while the initial speed was 1400km/s. Bz predicted: -28 … -42 nT Dst predicted: (-250 … -330)+ΔDst 2 = -400…-480 March 13-15, 1989, Time, UT Dst Index, nT Storm Forecast Routine is Based on the F1 and F2 Storm Forecast Routine is Based on the F1 and F2 •Sign of the Bz in the IMF, sign •CME’s proje cted speed, V •The inten sity of the Bz: Bz=F1(V) x sign •The inten sity of a geomagnetic storm Dst = F2(Bz) •Publishing the We used the functions F1 and F2 to analyze the March 13, 1989 geomagnetic storm (solid line in the figure on the right shows corresponding Dst index). This was a three step storm, therefore we assume that three CMEs may have caused it. First, we determined the source regions and the initial speed of the CMEs, then we calculated the Bz in the corresponding magnetic clouds and the range of the Dst index during the storms (blue boxes). Predicted Range of the Dst F1 F1 F2 F2
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How the Intensity of Geomagnetic Storms can be Determined from Solar Data. Vasyl Yurchyshyn, Big Bear Solar Observatory, 40386 North Shore Lane, Big Bear City, CA 92314, [email protected]. - PowerPoint PPT Presentation
Transcript of How the Intensity of Geomagnetic Storms can be Determined from Solar Data
How the Intensity of Geomagnetic Storms can be Determined from How the Intensity of Geomagnetic Storms can be Determined from Solar DataSolar Data
Coronal Mass Ejections (CMEs) are correlated with geomagnetic storms, which are a response of Coronal Mass Ejections (CMEs) are correlated with geomagnetic storms, which are a response of the magnetosphere to an action of the southward interplanetary magnetic field (IMF). We discuss the magnetosphere to an action of the southward interplanetary magnetic field (IMF). We discuss a new method to produce forecast of the intensity of a geomagnetic storm at least 1 day in a new method to produce forecast of the intensity of a geomagnetic storm at least 1 day in advance based solar data.advance based solar data.
Vasyl Yurchyshyn, Big Bear Solar Observatory, 40386 North Shore Lane, Big Bear City, CA 92314, [email protected] Yurchyshyn, Big Bear Solar Observatory, 40386 North Shore Lane, Big Bear City, CA 92314, [email protected]
1. We found that the CME 1. We found that the CME projection speed is related to projection speed is related to
the Bz in IMF :the Bz in IMF :
Fig. 1Fig. 1 The hourly averaged Bz measured The hourly averaged Bz measured at the front of an ejecta (ACE, GSM) vs at the front of an ejecta (ACE, GSM) vs the projected speed of CMEs. The solid the projected speed of CMEs. The solid line is an exponential fit: line is an exponential fit: F1=Bz[nT]=12.3+0.7exp(V/404).F1=Bz[nT]=12.3+0.7exp(V/404). The The dashed lines show r.m.s=7nT.dashed lines show r.m.s=7nT.
2. In turn, the Bz in IMF 2. In turn, the Bz in IMF defines the intensity (the Dst defines the intensity (the Dst
Index) of a stormIndex) of a storm
Fig. 2Fig. 2 The Dst index vs the hourly averaged The Dst index vs the hourly averaged Bz. The solid line is a 3Bz. The solid line is a 3rdrd degree polinominal degree polinominal fit, fit, F2F2, and the dashed lines show , and the dashed lines show
r.m.s=33nTr.m.s=33nT..
The X4.5/3B flare at 18:46UT on March 10, 1989 produced 1st CME, which arrived on March 13 at 02:00UT. Its travel speed was about 760km/s, while the initial speed was 1000km/s.
Bz predicted: -10 … -24 nT
Dst predicted: -100 … -180 nT
The X1.0/2B flare on March 11 at 15:33UT produced 2nd CME, which arrived on March 13 at 10:00UT. Its travel speed was about 990km/s, while the initial speed was 1100km/s.
Bz predicted: -13 … -27 nT
Dst predicted: (-120 … -190)+ΔDst1 = -210…-280
ΔDst1
ΔDst2
The M6.7/1n flare on March 12 at 08:16UT produced 3rd CME, which arrived on March 14 at 19:00UT. Its travel speed was about 1200km/s, while the initial speed was 1400km/s.
Bz predicted: -28 … -42 nT
Dst predicted: (-250 … -330)+ΔDst2 = -400…-480
March 13-15, 1989, Time, UT
Dst
Ind
ex,
nT
Storm Forecast Routine is Based on the F1 Storm Forecast Routine is Based on the F1 and F2and F2
•Sign of the Bz in
the IMF, sign•CME’s
projected
speed, V•The intensity
of the Bz: Bz=F1(V) x
sign•The intensity
of a geomagnetic storm Dst = F2(Bz)•Publishing the results at:bbso.njit.edu/~vayur/halo_
cme
We used the functions F1 and F2 to analyze the March 13, 1989 geomagnetic storm (solid line in the figure on the right shows corresponding Dst index). This was a three step storm, therefore we assume that three CMEs may have caused it. First, we determined the source regions and the initial speed of the CMEs, then we calculated the Bz in the corresponding magnetic clouds and the range of the Dst index during the storms (blue boxes). Predicted Range of the
Dst
F1F1
F2F2
