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Two-step forecast of geomagnetic storm using coronal mass ejection and solar wind condition.

Kim RS, Moon YJ, Gopalswamy N, Park YD, Kim YH - Space Weather (2014)

Bottom Line: To forecast geomagnetic storms, we had examined initially observed parameters of coronal mass ejections (CMEs) and introduced an empirical storm forecast model in a previous study.However, the latter produces better forecasts for 24 nonstorm events (88%), while the former correctly forecasts only 71% of them.We then performed the two-step forecast.

View Article: PubMed Central - PubMed

Affiliation: Astronomy and Space Program Division, Korea Astronomy and Space Science Institute Daejeon, South Korea.

ABSTRACT

To forecast geomagnetic storms, we had examined initially observed parameters of coronal mass ejections (CMEs) and introduced an empirical storm forecast model in a previous study. Now we suggest a two-step forecast considering not only CME parameters observed in the solar vicinity but also solar wind conditions near Earth to improve the forecast capability. We consider the empirical solar wind criteria derived in this study (B z  ≤ -5 nT or E y  ≥ 3 mV/m for t≥ 2 h for moderate storms with minimum Dst less than -50 nT) and a Dst model developed by Temerin and Li (2002, 2006) (TL model). Using 55 CME-Dst pairs during 1997 to 2003, our solar wind criteria produce slightly better forecasts for 31 storm events (90%) than the forecasts based on the TL model (87%). However, the latter produces better forecasts for 24 nonstorm events (88%), while the former correctly forecasts only 71% of them. We then performed the two-step forecast. The results are as follows: (i) for 15 events that are incorrectly forecasted using CME parameters, 12 cases (80%) can be properly predicted based on solar wind conditions; (ii) if we forecast a storm when both CME and solar wind conditions are satisfied (∩), the critical success index becomes higher than that from the forecast using CME parameters alone, however, only 25 storm events (81%) are correctly forecasted; and (iii) if we forecast a storm when either set of these conditions is satisfied (∪), all geomagnetic storms are correctly forecasted.

No MeSH data available.


Related in: MedlinePlus

(a) Time profiles of solar wind parameters and (b) observed and estimated Dst indices corresponding to a CME occurred at 06:10 UT on 4 November 1997. Two vertical solid lines indicate CME appearance time in the LASCO field of view and predicted arrival time at the Earth, respectively. Two vertical dotted lines delineate the ±24 h time window of the predicted CME arrival time at the Earth.
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fig01: (a) Time profiles of solar wind parameters and (b) observed and estimated Dst indices corresponding to a CME occurred at 06:10 UT on 4 November 1997. Two vertical solid lines indicate CME appearance time in the LASCO field of view and predicted arrival time at the Earth, respectively. Two vertical dotted lines delineate the ±24 h time window of the predicted CME arrival time at the Earth.

Mentions: To examine solar wind condition during geomagnetic storms, we use OMNI data from the Coordinated Data Analysis (Workshop) Web [King and Papitashvili, 2005]. The data set consists of hourly averaged definitive multispacecraft (mainly ACE (Advanced Composition Explorer) and Wind) solar wind parameters at 1 AU including magnetic field magnitude (Bx, By, Bz), electric field (Ey), ion number density (Ni), flow dynamic pressure (Pdyn), plasma flow speed (VSW), and plasma temperature (T). It also provides the Dst index from the World Data Center operated by the Data Analysis Center for Geomagnetism and Space Magnetism in Kyoto University. Figure 1 shows the time profiles of solar wind parameters and the Dst index. Two vertical solid lines indicate CME occurrence time (06:10 UT on 4 November 1997) and expected CME arrival time at the Earth (13:39 UT on 7 November 1997) from an empirical model [Gopalswamy et al., 2001], respectively. Two dotted vertical lines represent a ±24 h time window from the predicted CME arrival time. As shown in Figure 1a, a disturbance of solar wind parameters was observed at 00:30 UT on 7 November in all solar wind data, and the Dst index started to decrease and reached the minimum value of −110 nT at 04:30 UT as marked by blue line in Figure 1b. The predicted minimum Dst in this case was only −43 nT compared to the observed −110 nT representing a miss in the prediction of a storm event using CME parameters. In addition, the predicted time of Dst minimum was 9 h later than the observed.


Two-step forecast of geomagnetic storm using coronal mass ejection and solar wind condition.

Kim RS, Moon YJ, Gopalswamy N, Park YD, Kim YH - Space Weather (2014)

(a) Time profiles of solar wind parameters and (b) observed and estimated Dst indices corresponding to a CME occurred at 06:10 UT on 4 November 1997. Two vertical solid lines indicate CME appearance time in the LASCO field of view and predicted arrival time at the Earth, respectively. Two vertical dotted lines delineate the ±24 h time window of the predicted CME arrival time at the Earth.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4508932&req=5

fig01: (a) Time profiles of solar wind parameters and (b) observed and estimated Dst indices corresponding to a CME occurred at 06:10 UT on 4 November 1997. Two vertical solid lines indicate CME appearance time in the LASCO field of view and predicted arrival time at the Earth, respectively. Two vertical dotted lines delineate the ±24 h time window of the predicted CME arrival time at the Earth.
Mentions: To examine solar wind condition during geomagnetic storms, we use OMNI data from the Coordinated Data Analysis (Workshop) Web [King and Papitashvili, 2005]. The data set consists of hourly averaged definitive multispacecraft (mainly ACE (Advanced Composition Explorer) and Wind) solar wind parameters at 1 AU including magnetic field magnitude (Bx, By, Bz), electric field (Ey), ion number density (Ni), flow dynamic pressure (Pdyn), plasma flow speed (VSW), and plasma temperature (T). It also provides the Dst index from the World Data Center operated by the Data Analysis Center for Geomagnetism and Space Magnetism in Kyoto University. Figure 1 shows the time profiles of solar wind parameters and the Dst index. Two vertical solid lines indicate CME occurrence time (06:10 UT on 4 November 1997) and expected CME arrival time at the Earth (13:39 UT on 7 November 1997) from an empirical model [Gopalswamy et al., 2001], respectively. Two dotted vertical lines represent a ±24 h time window from the predicted CME arrival time. As shown in Figure 1a, a disturbance of solar wind parameters was observed at 00:30 UT on 7 November in all solar wind data, and the Dst index started to decrease and reached the minimum value of −110 nT at 04:30 UT as marked by blue line in Figure 1b. The predicted minimum Dst in this case was only −43 nT compared to the observed −110 nT representing a miss in the prediction of a storm event using CME parameters. In addition, the predicted time of Dst minimum was 9 h later than the observed.

Bottom Line: To forecast geomagnetic storms, we had examined initially observed parameters of coronal mass ejections (CMEs) and introduced an empirical storm forecast model in a previous study.However, the latter produces better forecasts for 24 nonstorm events (88%), while the former correctly forecasts only 71% of them.We then performed the two-step forecast.

View Article: PubMed Central - PubMed

Affiliation: Astronomy and Space Program Division, Korea Astronomy and Space Science Institute Daejeon, South Korea.

ABSTRACT

To forecast geomagnetic storms, we had examined initially observed parameters of coronal mass ejections (CMEs) and introduced an empirical storm forecast model in a previous study. Now we suggest a two-step forecast considering not only CME parameters observed in the solar vicinity but also solar wind conditions near Earth to improve the forecast capability. We consider the empirical solar wind criteria derived in this study (B z  ≤ -5 nT or E y  ≥ 3 mV/m for t≥ 2 h for moderate storms with minimum Dst less than -50 nT) and a Dst model developed by Temerin and Li (2002, 2006) (TL model). Using 55 CME-Dst pairs during 1997 to 2003, our solar wind criteria produce slightly better forecasts for 31 storm events (90%) than the forecasts based on the TL model (87%). However, the latter produces better forecasts for 24 nonstorm events (88%), while the former correctly forecasts only 71% of them. We then performed the two-step forecast. The results are as follows: (i) for 15 events that are incorrectly forecasted using CME parameters, 12 cases (80%) can be properly predicted based on solar wind conditions; (ii) if we forecast a storm when both CME and solar wind conditions are satisfied (∩), the critical success index becomes higher than that from the forecast using CME parameters alone, however, only 25 storm events (81%) are correctly forecasted; and (iii) if we forecast a storm when either set of these conditions is satisfied (∪), all geomagnetic storms are correctly forecasted.

No MeSH data available.


Related in: MedlinePlus