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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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Related in: MedlinePlus

The Arctic TEC time series and corresponding solar activity condition of the time period. Top (A) Time series of the SCHA-derived Arctic mean TEC (black) and the GIM-derived Arctic mean TEC (cyan) and the reconstructed periodic oscillation component of the Arctic mean TEC based on the four periods (magenta). Middle (B) The difference between the SCHA- and GIM-derived mean TEC (cyan) and the mean of the difference (black). Bottom (C) The 10.7-cm radio flux for 2000–2013, indicating solar activity conditions.
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pone-0111497-g002: The Arctic TEC time series and corresponding solar activity condition of the time period. Top (A) Time series of the SCHA-derived Arctic mean TEC (black) and the GIM-derived Arctic mean TEC (cyan) and the reconstructed periodic oscillation component of the Arctic mean TEC based on the four periods (magenta). Middle (B) The difference between the SCHA- and GIM-derived mean TEC (cyan) and the mean of the difference (black). Bottom (C) The 10.7-cm radio flux for 2000–2013, indicating solar activity conditions.

Mentions: The top panel of Figure 2 shows the time series of the SCHA-derived Arctic mean TEC (black line) and the GIM-derived Arctic mean TEC (cyan line). The two time series have a high correlation coefficient of 0.9613. Over the whole time period, the mean difference between the two time series is 2.01 TECU with a standard deviation of 2.20 TECU, as shown in the middle panel of Figure 2. The SCHA-derived Arctic mean TEC is larger than the GIM-derived result under active ionosphere conditions (2000–2003 and 2012–2013), which is indicated by the F10.7 index showed in the bottom panel of Figure 2, while the two time series are comparable under calm ionosphere conditions (2008–2009). This observation indicates that the GIM-derived Arctic mean TEC is “averaged” by the global coverage, which is consistent with the conclusions regarding the hemisphere and latitude-band distribution of the mean TEC in [16]–[17], [36].


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)

The Arctic TEC time series and corresponding solar activity condition of the time period. Top (A) Time series of the SCHA-derived Arctic mean TEC (black) and the GIM-derived Arctic mean TEC (cyan) and the reconstructed periodic oscillation component of the Arctic mean TEC based on the four periods (magenta). Middle (B) The difference between the SCHA- and GIM-derived mean TEC (cyan) and the mean of the difference (black). Bottom (C) The 10.7-cm radio flux for 2000–2013, indicating solar activity conditions.
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Related In: Results  -  Collection

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

pone-0111497-g002: The Arctic TEC time series and corresponding solar activity condition of the time period. Top (A) Time series of the SCHA-derived Arctic mean TEC (black) and the GIM-derived Arctic mean TEC (cyan) and the reconstructed periodic oscillation component of the Arctic mean TEC based on the four periods (magenta). Middle (B) The difference between the SCHA- and GIM-derived mean TEC (cyan) and the mean of the difference (black). Bottom (C) The 10.7-cm radio flux for 2000–2013, indicating solar activity conditions.
Mentions: The top panel of Figure 2 shows the time series of the SCHA-derived Arctic mean TEC (black line) and the GIM-derived Arctic mean TEC (cyan line). The two time series have a high correlation coefficient of 0.9613. Over the whole time period, the mean difference between the two time series is 2.01 TECU with a standard deviation of 2.20 TECU, as shown in the middle panel of Figure 2. The SCHA-derived Arctic mean TEC is larger than the GIM-derived result under active ionosphere conditions (2000–2003 and 2012–2013), which is indicated by the F10.7 index showed in the bottom panel of Figure 2, while the two time series are comparable under calm ionosphere conditions (2008–2009). This observation indicates that the GIM-derived Arctic mean TEC is “averaged” by the global coverage, which is consistent with the conclusions regarding the hemisphere and latitude-band distribution of the mean TEC in [16]–[17], [36].

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
Related in: MedlinePlus