In this work,the ionospheric variability is analyzed by applying the wavelet decomposition technique to the noontime fo F2,F10.7,interplanetary magnetic field(IMF)Bz,Ap,and lower thermospheric temperature at pressure ...In this work,the ionospheric variability is analyzed by applying the wavelet decomposition technique to the noontime fo F2,F10.7,interplanetary magnetic field(IMF)Bz,Ap,and lower thermospheric temperature at pressure of 10?4 h Pa in 2002.Results show that the variance of periodic oscillations in the ionosphere is largest in the 2–4-day period and declines with the increase of the period.The maximum variance of the periodic oscillations in solar irradiation is in the 16–32-day period.For geomagnetic activities,most of the variance is about equally distributed on intervals of periods shorter than 32 days.Variance distributions of IMF Bz and lower thermospheric temperature are similar to those of the ionosphere.They show the maximum in the 2–4-day period and decline with the increase of the period.By analyzing the distributions of the variances,the potential connections between the ionosphere and the external sources are discussed.展开更多
A higher correlation tends to yield a more accurate prediction,so that a correlation as high as possible has been searched for and employed in the prediction of solar activity.Instead of using geomagnetic activity dur...A higher correlation tends to yield a more accurate prediction,so that a correlation as high as possible has been searched for and employed in the prediction of solar activity.Instead of using geomagnetic activity during the descending phase of the solar cycle,the minimum annual aa index (aa min) is used as an indicator for the ensuing maximum amplitude (R m) of the sunspot cycle.A four-cycle periodicity is roughly shown in the correlation between R m and aa min.The widely accepted Ohl's precursor prediction method often fails due to the prediction error relative to its estimated uncertainty.An accurate prediction depends on the positive variation of the correlation rather than a higher correlation.Previous experiences by using this method indicate that a prediction for the next cycle,R m (24)=80 ± 17,is likely to fail,implying that the sunspot maximum of Cycle 24 may be either smaller than 63 or greater than 97.展开更多
The ionosphere is composed of a large number of electrons and ions, which are produced by the photoionization effect of the solar radiation on the neutral atmosphere. The altitude range of ionosphere is about 60–1000...The ionosphere is composed of a large number of electrons and ions, which are produced by the photoionization effect of the solar radiation on the neutral atmosphere. The altitude range of ionosphere is about 60–1000 km and varies with local time and other factors （e.g., solar and geomagnetic activity）. Although the ionosphere varies over multiply timescales, the diurnal variation is in the dominant position due to the sun’s photoionization effect.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.41174134 and 41274156)the National Basic Research Program of China("973"Project)(Grant No.2011CB811405)
文摘In this work,the ionospheric variability is analyzed by applying the wavelet decomposition technique to the noontime fo F2,F10.7,interplanetary magnetic field(IMF)Bz,Ap,and lower thermospheric temperature at pressure of 10?4 h Pa in 2002.Results show that the variance of periodic oscillations in the ionosphere is largest in the 2–4-day period and declines with the increase of the period.The maximum variance of the periodic oscillations in solar irradiation is in the 16–32-day period.For geomagnetic activities,most of the variance is about equally distributed on intervals of periods shorter than 32 days.Variance distributions of IMF Bz and lower thermospheric temperature are similar to those of the ionosphere.They show the maximum in the 2–4-day period and decline with the increase of the period.By analyzing the distributions of the variances,the potential connections between the ionosphere and the external sources are discussed.
基金supported by the Chinese Academy of Sciences (Grant No.KGCX3-SYW-403-10)the National Natural Science Foundation of China (Grant Nos.10973020,10673017 and 40890161)
文摘A higher correlation tends to yield a more accurate prediction,so that a correlation as high as possible has been searched for and employed in the prediction of solar activity.Instead of using geomagnetic activity during the descending phase of the solar cycle,the minimum annual aa index (aa min) is used as an indicator for the ensuing maximum amplitude (R m) of the sunspot cycle.A four-cycle periodicity is roughly shown in the correlation between R m and aa min.The widely accepted Ohl's precursor prediction method often fails due to the prediction error relative to its estimated uncertainty.An accurate prediction depends on the positive variation of the correlation rather than a higher correlation.Previous experiences by using this method indicate that a prediction for the next cycle,R m (24)=80 ± 17,is likely to fail,implying that the sunspot maximum of Cycle 24 may be either smaller than 63 or greater than 97.
文摘The ionosphere is composed of a large number of electrons and ions, which are produced by the photoionization effect of the solar radiation on the neutral atmosphere. The altitude range of ionosphere is about 60–1000 km and varies with local time and other factors （e.g., solar and geomagnetic activity）. Although the ionosphere varies over multiply timescales, the diurnal variation is in the dominant position due to the sun’s photoionization effect.
