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Long-term prediction of the Arctic ionospheric TEC based on time-varying periodograms.

Liu J, Chen R, Wang Z, An J, Hyyppä J - PLoS ONE (2014)

Bottom Line: The TEC time series is divided into two components of periodic oscillations and the average TEC.The backward prediction indicates that the Arctic TEC variability includes a 9 years period for the study duration, in addition to the well-established periods.The long-term prediction has an uncertainty of 4.8-5.6 TECU for different period sets.

View Article: PubMed Central - PubMed

Affiliation: Department of remote sensing and photogrammetry, Finnish Geodetic Institute, Masala, Finland.

ABSTRACT
Knowledge of the polar ionospheric total electron content (TEC) and its future variations is of scientific and engineering relevance. In this study, a new method is developed to predict Arctic mean TEC on the scale of a solar cycle using previous data covering 14 years. The Arctic TEC is derived from global positioning system measurements using the spherical cap harmonic analysis mapping method. The study indicates that the variability of the Arctic TEC results in highly time-varying periodograms, which are utilized for prediction in the proposed method. The TEC time series is divided into two components of periodic oscillations and the average TEC. The newly developed method of TEC prediction is based on an extrapolation method that requires no input of physical observations of the time interval of prediction, and it is performed in both temporally backward and forward directions by summing the extrapolation of the two components. The backward prediction indicates that the Arctic TEC variability includes a 9 years period for the study duration, in addition to the well-established periods. The long-term prediction has an uncertainty of 4.8-5.6 TECU for different period sets.

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Backward predicted Arctic mean TEC for 1988–1999 and the corresponding geographical indices.Top: Backward predicted Arctic mean TEC for 1988–1999 based on different period sets of the average TEC, in addition with the GIM-derived Arctic mean TEC for 1995–1999. Negative TEC values are set to zero. Middle: Solar indices for 1988–1999, including the sunspot number and the 10.7-cm radio flux. Bottom: The geomagnetic index () for 1988–1999.
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pone-0111497-g005: Backward predicted Arctic mean TEC for 1988–1999 and the corresponding geographical indices.Top: Backward predicted Arctic mean TEC for 1988–1999 based on different period sets of the average TEC, in addition with the GIM-derived Arctic mean TEC for 1995–1999. Negative TEC values are set to zero. Middle: Solar indices for 1988–1999, including the sunspot number and the 10.7-cm radio flux. Bottom: The geomagnetic index () for 1988–1999.

Mentions: The four oscillation components are extrapolated temporally based on their time-varying periodograms, as discussed in Section 3. For the average TEC prediction, this study compares the results of three sets of selected periods: A) the four well-established periods: 11.2 years, 2 years, 1 year and 0.5 years; B) the above four periods plus the 5.6 years period; C) the above four periods plus the 9 years period. Figure 5 shows the results of the backward prediction, which are the summation of the predicted oscillation components and the average TEC, for the preceding 11.2 years, from October 1988 to December 1999. The prediction results are set to zero when the values are negative. For purposes of comparison, Figure 5 also displays indices that are strongly correlated to the ionosphere for the same time period, including the solar sunspot number, the 10.7-cm solar radio flux and the geomagnetic index , which are used to examine the results of the backward prediction of the Arctic mean TEC.


Long-term prediction of the Arctic ionospheric TEC based on time-varying periodograms.

Liu J, Chen R, Wang Z, An J, Hyyppä J - PLoS ONE (2014)

Backward predicted Arctic mean TEC for 1988–1999 and the corresponding geographical indices.Top: Backward predicted Arctic mean TEC for 1988–1999 based on different period sets of the average TEC, in addition with the GIM-derived Arctic mean TEC for 1995–1999. Negative TEC values are set to zero. Middle: Solar indices for 1988–1999, including the sunspot number and the 10.7-cm radio flux. Bottom: The geomagnetic index () for 1988–1999.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4219753&req=5

pone-0111497-g005: Backward predicted Arctic mean TEC for 1988–1999 and the corresponding geographical indices.Top: Backward predicted Arctic mean TEC for 1988–1999 based on different period sets of the average TEC, in addition with the GIM-derived Arctic mean TEC for 1995–1999. Negative TEC values are set to zero. Middle: Solar indices for 1988–1999, including the sunspot number and the 10.7-cm radio flux. Bottom: The geomagnetic index () for 1988–1999.
Mentions: The four oscillation components are extrapolated temporally based on their time-varying periodograms, as discussed in Section 3. For the average TEC prediction, this study compares the results of three sets of selected periods: A) the four well-established periods: 11.2 years, 2 years, 1 year and 0.5 years; B) the above four periods plus the 5.6 years period; C) the above four periods plus the 9 years period. Figure 5 shows the results of the backward prediction, which are the summation of the predicted oscillation components and the average TEC, for the preceding 11.2 years, from October 1988 to December 1999. The prediction results are set to zero when the values are negative. For purposes of comparison, Figure 5 also displays indices that are strongly correlated to the ionosphere for the same time period, including the solar sunspot number, the 10.7-cm solar radio flux and the geomagnetic index , which are used to examine the results of the backward prediction of the Arctic mean TEC.

Bottom Line: The TEC time series is divided into two components of periodic oscillations and the average TEC.The backward prediction indicates that the Arctic TEC variability includes a 9 years period for the study duration, in addition to the well-established periods.The long-term prediction has an uncertainty of 4.8-5.6 TECU for different period sets.

View Article: PubMed Central - PubMed

Affiliation: Department of remote sensing and photogrammetry, Finnish Geodetic Institute, Masala, Finland.

ABSTRACT
Knowledge of the polar ionospheric total electron content (TEC) and its future variations is of scientific and engineering relevance. In this study, a new method is developed to predict Arctic mean TEC on the scale of a solar cycle using previous data covering 14 years. The Arctic TEC is derived from global positioning system measurements using the spherical cap harmonic analysis mapping method. The study indicates that the variability of the Arctic TEC results in highly time-varying periodograms, which are utilized for prediction in the proposed method. The TEC time series is divided into two components of periodic oscillations and the average TEC. The newly developed method of TEC prediction is based on an extrapolation method that requires no input of physical observations of the time interval of prediction, and it is performed in both temporally backward and forward directions by summing the extrapolation of the two components. The backward prediction indicates that the Arctic TEC variability includes a 9 years period for the study duration, in addition to the well-established periods. The long-term prediction has an uncertainty of 4.8-5.6 TECU for different period sets.

Show MeSH