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MAG4 versus alternative techniques for forecasting active region flare productivity.

Falconer DA, Moore RL, Barghouty AF, Khazanov I - Space Weather (2014)

Bottom Line: We present a statistical method of measuring the difference in performance between MAG4 and comparable alternative techniques that forecast an active region's major-flare productivity from alternative observed aspects of the active region.We find that (1) Present MAG4 far outperforms both McIntosh Active-Region Class and Total Magnetic Flux, (2) Next MAG4 significantly outperforms Present MAG4, (3) the performance of Next MAG4 is insensitive to the forward and backward temporal windows used, in the range of one to a few days, and (4) forecasting from the free-energy proxy in combination with either any broad category of McIntosh active-region classes or any Mount Wilson active-region class gives no significant performance improvement over forecasting from the free-energy proxy alone (Present MAG4).Quantitative comparison of performance of pairs of forecasting techniques Next MAG4 forecasts major flares more accurately than Present MAG4 Present MAG4 forecast outperforms McIntosh AR Class and total magnetic flux.

View Article: PubMed Central - PubMed

Affiliation: Heliophysics and Planetary Science Office ZP13 MSFC/NASA Huntsville, Alabama, USA ; Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville Huntsville, Alabama, USA.

ABSTRACT

: MAG4 is a technique of forecasting an active region's rate of production of major flares in the coming few days from a free magnetic energy proxy. We present a statistical method of measuring the difference in performance between MAG4 and comparable alternative techniques that forecast an active region's major-flare productivity from alternative observed aspects of the active region. We demonstrate the method by measuring the difference in performance between the "Present MAG4" technique and each of three alternative techniques, called "McIntosh Active-Region Class," "Total Magnetic Flux," and "Next MAG4." We do this by using (1) the MAG4 database of magnetograms and major flare histories of sunspot active regions, (2) the NOAA table of the major-flare productivity of each of 60 McIntosh active-region classes of sunspot active regions, and (3) five technique performance metrics (Heidke Skill Score, True Skill Score, Percent Correct, Probability of Detection, and False Alarm Rate) evaluated from 2000 random two-by-two contingency tables obtained from the databases. We find that (1) Present MAG4 far outperforms both McIntosh Active-Region Class and Total Magnetic Flux, (2) Next MAG4 significantly outperforms Present MAG4, (3) the performance of Next MAG4 is insensitive to the forward and backward temporal windows used, in the range of one to a few days, and (4) forecasting from the free-energy proxy in combination with either any broad category of McIntosh active-region classes or any Mount Wilson active-region class gives no significant performance improvement over forecasting from the free-energy proxy alone (Present MAG4).

Key points: Quantitative comparison of performance of pairs of forecasting techniques Next MAG4 forecasts major flares more accurately than Present MAG4 Present MAG4 forecast outperforms McIntosh AR Class and total magnetic flux.

No MeSH data available.


Related in: MedlinePlus

The strong-field intervals of the neutral lines in a MDI magnetogram of a δ sunspot active region that produced an X-class flare and CME. The polarity, strength, and distribution of the line-of-sight flux are mapped by the gray scale image. The polarity is positive (negative) in light (dark) areas. The strong-field intervals of the neutral lines are traced by the colored curves. The color gives the strength of the gradient of the line-of-sight field (/∇BLOS/) at these neutral lines in units of G/Mm. The lightest color is for /∇BLOS/ ≥ 500 G/Mm, the range of the extreme gradients at the interval of the neutral line in the large δ sunspot.
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fig01: The strong-field intervals of the neutral lines in a MDI magnetogram of a δ sunspot active region that produced an X-class flare and CME. The polarity, strength, and distribution of the line-of-sight flux are mapped by the gray scale image. The polarity is positive (negative) in light (dark) areas. The strong-field intervals of the neutral lines are traced by the colored curves. The color gives the strength of the gradient of the line-of-sight field (/∇BLOS/) at these neutral lines in units of G/Mm. The lightest color is for /∇BLOS/ ≥ 500 G/Mm, the range of the extreme gradients at the interval of the neutral line in the large δ sunspot.

Mentions: The other two magnetogram measures are neutral-line measures. One is the length of strong-field neutral line,3where the integral is over those neutral-line segments that fulfill the above three conditions (defined in the previous paragraph) in the AR's line-of-sight magnetogram (see the example AR magnetogram in Figure 1), comprising the strong-field intervals of the neutral lines. The other neutral-line measure is a proxy of the AR's free magnetic energy:4where LWLSG is the gradient-weighted length of strong-field neutral line (the LOS approximation).


MAG4 versus alternative techniques for forecasting active region flare productivity.

Falconer DA, Moore RL, Barghouty AF, Khazanov I - Space Weather (2014)

The strong-field intervals of the neutral lines in a MDI magnetogram of a δ sunspot active region that produced an X-class flare and CME. The polarity, strength, and distribution of the line-of-sight flux are mapped by the gray scale image. The polarity is positive (negative) in light (dark) areas. The strong-field intervals of the neutral lines are traced by the colored curves. The color gives the strength of the gradient of the line-of-sight field (/∇BLOS/) at these neutral lines in units of G/Mm. The lightest color is for /∇BLOS/ ≥ 500 G/Mm, the range of the extreme gradients at the interval of the neutral line in the large δ sunspot.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4508933&req=5

fig01: The strong-field intervals of the neutral lines in a MDI magnetogram of a δ sunspot active region that produced an X-class flare and CME. The polarity, strength, and distribution of the line-of-sight flux are mapped by the gray scale image. The polarity is positive (negative) in light (dark) areas. The strong-field intervals of the neutral lines are traced by the colored curves. The color gives the strength of the gradient of the line-of-sight field (/∇BLOS/) at these neutral lines in units of G/Mm. The lightest color is for /∇BLOS/ ≥ 500 G/Mm, the range of the extreme gradients at the interval of the neutral line in the large δ sunspot.
Mentions: The other two magnetogram measures are neutral-line measures. One is the length of strong-field neutral line,3where the integral is over those neutral-line segments that fulfill the above three conditions (defined in the previous paragraph) in the AR's line-of-sight magnetogram (see the example AR magnetogram in Figure 1), comprising the strong-field intervals of the neutral lines. The other neutral-line measure is a proxy of the AR's free magnetic energy:4where LWLSG is the gradient-weighted length of strong-field neutral line (the LOS approximation).

Bottom Line: We present a statistical method of measuring the difference in performance between MAG4 and comparable alternative techniques that forecast an active region's major-flare productivity from alternative observed aspects of the active region.We find that (1) Present MAG4 far outperforms both McIntosh Active-Region Class and Total Magnetic Flux, (2) Next MAG4 significantly outperforms Present MAG4, (3) the performance of Next MAG4 is insensitive to the forward and backward temporal windows used, in the range of one to a few days, and (4) forecasting from the free-energy proxy in combination with either any broad category of McIntosh active-region classes or any Mount Wilson active-region class gives no significant performance improvement over forecasting from the free-energy proxy alone (Present MAG4).Quantitative comparison of performance of pairs of forecasting techniques Next MAG4 forecasts major flares more accurately than Present MAG4 Present MAG4 forecast outperforms McIntosh AR Class and total magnetic flux.

View Article: PubMed Central - PubMed

Affiliation: Heliophysics and Planetary Science Office ZP13 MSFC/NASA Huntsville, Alabama, USA ; Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville Huntsville, Alabama, USA.

ABSTRACT

: MAG4 is a technique of forecasting an active region's rate of production of major flares in the coming few days from a free magnetic energy proxy. We present a statistical method of measuring the difference in performance between MAG4 and comparable alternative techniques that forecast an active region's major-flare productivity from alternative observed aspects of the active region. We demonstrate the method by measuring the difference in performance between the "Present MAG4" technique and each of three alternative techniques, called "McIntosh Active-Region Class," "Total Magnetic Flux," and "Next MAG4." We do this by using (1) the MAG4 database of magnetograms and major flare histories of sunspot active regions, (2) the NOAA table of the major-flare productivity of each of 60 McIntosh active-region classes of sunspot active regions, and (3) five technique performance metrics (Heidke Skill Score, True Skill Score, Percent Correct, Probability of Detection, and False Alarm Rate) evaluated from 2000 random two-by-two contingency tables obtained from the databases. We find that (1) Present MAG4 far outperforms both McIntosh Active-Region Class and Total Magnetic Flux, (2) Next MAG4 significantly outperforms Present MAG4, (3) the performance of Next MAG4 is insensitive to the forward and backward temporal windows used, in the range of one to a few days, and (4) forecasting from the free-energy proxy in combination with either any broad category of McIntosh active-region classes or any Mount Wilson active-region class gives no significant performance improvement over forecasting from the free-energy proxy alone (Present MAG4).

Key points: Quantitative comparison of performance of pairs of forecasting techniques Next MAG4 forecasts major flares more accurately than Present MAG4 Present MAG4 forecast outperforms McIntosh AR Class and total magnetic flux.

No MeSH data available.


Related in: MedlinePlus