A Signature of 27 day Solar Rotation in the Concentration of Metallic Ions within the Terrestrial Ionosphere

Abstract

We present observations during the interval 2006-2014 of 27 day and 13.5 day periodic oscillations in the ionospheric sporadic E (Es) layer. This is a thin, dense layer composed of metallic ions in the Earth's upper atmosphere between 90 and 130 km. Lomb-Scargle spectral and wavelet analyses reveal that these pronounced periodicities observed from ground-based ionosondes and GPS/GNSS radio occultations are associated with highspeed solar winds generated from persistent coronal holes on successive 27 day solar rotations. The 27 day and 13.5 day oscillations in the Es layers are dependent on latitude, showing a higher magnitude of periodicities at low latitudes between 0°and 15°and at high latitudes between 45°and 90°(10%-14%) than those at midlatitudes between 15°and 45°(4%-10%). The 27 day and 13.5 day oscillations in the high-latitude Es layers correlate well with the geomagnetic activity Dst and Ap indices, and these periodic oscillations become more significant at the solar maximum (2000-2003 and 2011-2014) than at the solar minimum.

An Empirical Model of the Ionospheric Sporadic E Layer Based on GNSS Radio Occultation Data

“…The model overestimated small S4max values and underestimated large S4max values. This is because, in this study, the model provides a climatology of E s layers, while other electrodynamic processes, for example, the neutral wind shear effect on the vertical motion of ions (Yu et al, 2019) and the geomagnetic activity effect on the significant periodic oscillations in E s layers (Yu, Scott, Xue, Yue, Chi, et al, 2021) satellite RO measurements, although the prediction of E s layers is severely constrained at present due to a lack of sufficient thermospheric wind data. Figure 10 shows the global distributions of the intensity of E s layers at 0 UT in the four seasons, represented by S4max from satellite RO observations and the model outputs in the period 2006-2014.…”

“…The short-term variations in the low-and high-latitude E s layers are associated with fast solar wind streams (Davies, 1990;L. Resende et al, 2021) and recurrent geomagnetic activity (Yu, Scott, Xue, Yue, Chi, et al, 2021).…”

“…Besides, the influences of solar activity, equatorial electrojet current plasma instabilities, and geomagnetic disturbances are not yet included in the model. The short‐term variations in the low‐ and high‐latitude E s layers are associated with fast solar wind streams (Davies, 1990; L. Resende et al., 2021) and recurrent geomagnetic activity (Yu, Scott, Xue, Yue, Chi, et al., 2021).…”

Modulation of Solar Wind Impact on the Earth’s Magnetosphere during the Solar Cycle

“…In fact, such a temporal lag represents the average of the broadly distributed shift times between the two datasets, or, in other words, the time required for the various geo-effective structures to transit from L1 to the Earth. The signature of the 27-day solar rotation is evident in the secondary peaks observed during the minimum period [32,33]. Therefore, to determine the influence of the SW energy on geo-effectiveness, in the following analysis, the energy time series are shifted backward by a time interval with respect to the Dst index: E(t) = E(t + ).…”

Predictive Capabilities of Corotating Interaction Regions Using STEREO and Wind In‐Situ Observations

“…If they reach down to the heliographic latitude of Earth, they sweep over the Earth once per solar rotation and cause a sequence of effects with a roughly 27‐day periodicity. These effects include recurrent geomagnetic storms (Chi et al., 2018; Echer et al., 2013; Jian et al., 2006), changes in the energetic particle environment on Earth (Rouillard & Lockwood, 2007), in the ionosphere (Yu et al., 2021), in the occurrence of lightning (C. J. Scott et al., 2014), and other meteorological processes in Earth's lower atmosphere (Harrison & Lockwood, 2020). In rare cases, CIRs can also cause intense geomagnetic storms (Chi et al., 2018; Gonzalez et al., 2011).…”