Characteristics of PMSE associated with the geomagnetic disturbance driven by corotating interaction region and high‐speed solar wind streams in the declining solar cycle 23

Abstract

We report interannual variations of the correlation between the reflectivity of polar mesospheric summer echoes (PMSEs) and solar wind parameters (speed and dynamic pressure), and AE index as a proxy of geomagnetic disturbances, and cosmic noise absorption (CNA) in the declining phase (2001–2008) of solar cycle 23. PMSEs are observed by 52 MHz VHF radar measurements at Esrange (67.8°N, 20.4°E), Sweden. In approaching the solar minimum years, high‐speed solar wind streams emanate from frequently emerging coronal holes, leading to 7, 9, and 13.5 day periodicities in their arrival at Earth. Periodicities of 7 and/or 9 days are found in PMSE reflectivity in 2005–2006 and 2008. Periodicity‐resolved correlations at 7 and 9 days of both D region ionization observed by cosmic noise absorption (CNA) and PMSE with solar wind speed and AE index vary from year to year but generally increase as solar minimum is approached. PMSEs have a higher periodicity‐resolved correlation with AE index than the solar wind speed. In addition, cross correlation of PMSE reflectivity with AE index is mostly higher than with CNA in solar minimum years (2005–2008). This can signify that high‐speed solar wind stream‐induced high‐energy particles possibly have strong influence on CNA, but not as much as on PMSE, especially for the years of significant periodicities occurring.

Dynamically Unstable Strong Wind Shears Observed in the Polar Mesosphere Summer Echo Layer Associated With Geomagnetic Disturbances

“…PMSE in summers of 2006 and 2008 in a solar declining phase exhibits periodic signatures at 7, 9, and 13.5 days by the effects of HSS (Lee et al, , ). It is intriguing whether strong shear occurrence in the PMSE is also associated with the effects of geomagnetic disturbance induced by HSS.…”

Polar Mesospheric Summer Echo Characteristics in Magnetic Local Time and Height Profiles

“…Recently, energetic electron precipitation induced by geomagnetic disturbance has been recognized as a significant contributor to PMSE production (Zeller & Bremer 2009;Kirkwood et al 2013;Lee et al 2013Lee et al , 2014Lee et al , 2015Lee et al , 2018Lee et al , 2020. During high-speed solar wind streams (HSSs), PMSE exhibits periodicities of 7, 9, and 13.5 days, in phase with solar wind speed and the auroral electrojet (AE) index (Lee et al 2013).…”

Observation of atomic oxygen O(1S) green‐line emission in the summer polar upper mesosphere associated with high‐energy (≥30 keV) electron precipitation during high‐speed solar wind streams

“…In addition, there have been significant observations of polar mesospheric summer echoes (PMSE) [ Cho and Röttger , ], as a precursor of polar mesospheric clouds (PMCs) ranging from altitudes of 70–90 km peaked at 82 km, in a link to high‐energy electron precipitation by HSS [e.g., Bremer et al , ; Lee et al ., , ]. The echoes are modulated in periodicities of 7, 9, and 13.5 days and correlated with the solar wind speed and AE index induced by HSSs [ Lee et al ., , ]. It is noticeable that PMSE associated with high‐energy electron precipitation can be observed in the region above an arctic circle of 65°N maintained in sunlit condition in summer.…”