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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

Prior durations of Bz and Ey disturbances according to new solar wind criteria are plotted against minimum Dst values for the storms. The vertical dotted lines indicate −50 nT, and the horizontal dotted lines indicate the durations of 2 h.
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fig05: Prior durations of Bz and Ey disturbances according to new solar wind criteria are plotted against minimum Dst values for the storms. The vertical dotted lines indicate −50 nT, and the horizontal dotted lines indicate the durations of 2 h.

Mentions: Therefore, we choose Bz ≤ −5 nT or Ey ≥ 3 mV/m for t≥ 2 h as new solar wind criteria for moderate storm. Figure 5 shows the durations of modified Bz and Ey criteria. The vertical dotted lines indicate −50 nT, and the horizontal dotted lines indicate the durations of 2 h. Among 31 moderate storms with minimum Dstless than −50 nT, 28 events (90%) satisfy these solar wind criteria.


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)

Prior durations of Bz and Ey disturbances according to new solar wind criteria are plotted against minimum Dst values for the storms. The vertical dotted lines indicate −50 nT, and the horizontal dotted lines indicate the durations of 2 h.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig05: Prior durations of Bz and Ey disturbances according to new solar wind criteria are plotted against minimum Dst values for the storms. The vertical dotted lines indicate −50 nT, and the horizontal dotted lines indicate the durations of 2 h.
Mentions: Therefore, we choose Bz ≤ −5 nT or Ey ≥ 3 mV/m for t≥ 2 h as new solar wind criteria for moderate storm. Figure 5 shows the durations of modified Bz and Ey criteria. The vertical dotted lines indicate −50 nT, and the horizontal dotted lines indicate the durations of 2 h. Among 31 moderate storms with minimum Dstless than −50 nT, 28 events (90%) satisfy these solar wind criteria.

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