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The Dst index underestimates the solar cycle variation of geomagnetic activity

View Article: PubMed Central - PubMed

ABSTRACT

It is known that the correction of the Kyoto Dst index for the secular variation of the Earth's internal field produces a discontinuity in the Kyoto Dst index at the end of each year. We show that this secular correction also introduces a significant baseline error to the Kyoto Dst index that leads to an underestimate of the solar cycle variation of geomagnetic activity and of the strength of the ring current as measured by the Kyoto Dst index. Thus, the average value of the Kyoto Dst index would be approximately 13 nT more negative for the active year 2003 compared to quiet years 2006 and 2009 if the Kyoto Dst index properly measured the effects of the ring current and other currents that influence the Dst observatories. Discontinuities in the Kyoto Dst index at the end of each year have an average value of about 5 nT, but the discontinuity at the end of year 2002 was approximately 12 nT, and the discontinuity at the end of year 1982 may have been as large as 20 nT.

No MeSH data available.


A comparison of the model output with the Kyoto Dst index for 3.5 months around the end of the year 2002. The baseline correction was applied to the model. The point of the figure is to show the good agreement between the model and the Kyoto Dst index.
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jgra51951-fig-0002: A comparison of the model output with the Kyoto Dst index for 3.5 months around the end of the year 2002. The baseline correction was applied to the model. The point of the figure is to show the good agreement between the model and the Kyoto Dst index.

Mentions: Figure 2 shows that the model with the baseline correction agrees well with the Kyoto Dst index.


The Dst index underestimates the solar cycle variation of geomagnetic activity
A comparison of the model output with the Kyoto Dst index for 3.5 months around the end of the year 2002. The baseline correction was applied to the model. The point of the figure is to show the good agreement between the model and the Kyoto Dst index.
© Copyright Policy - creativeCommonsBy-nc-nd
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036309&req=5

jgra51951-fig-0002: A comparison of the model output with the Kyoto Dst index for 3.5 months around the end of the year 2002. The baseline correction was applied to the model. The point of the figure is to show the good agreement between the model and the Kyoto Dst index.
Mentions: Figure 2 shows that the model with the baseline correction agrees well with the Kyoto Dst index.

View Article: PubMed Central - PubMed

ABSTRACT

It is known that the correction of the Kyoto Dst index for the secular variation of the Earth's internal field produces a discontinuity in the Kyoto Dst index at the end of each year. We show that this secular correction also introduces a significant baseline error to the Kyoto Dst index that leads to an underestimate of the solar cycle variation of geomagnetic activity and of the strength of the ring current as measured by the Kyoto Dst index. Thus, the average value of the Kyoto Dst index would be approximately 13 nT more negative for the active year 2003 compared to quiet years 2006 and 2009 if the Kyoto Dst index properly measured the effects of the ring current and other currents that influence the Dst observatories. Discontinuities in the Kyoto Dst index at the end of each year have an average value of about 5 nT, but the discontinuity at the end of year 2002 was approximately 12 nT, and the discontinuity at the end of year 1982 may have been as large as 20 nT.

No MeSH data available.