Analysis of wave-like oscillations in parameters of sporadic E layer and neutral atmosphere

作者：Mosna Z^*; Knizova P Koucka

来源：Journal of Atmospheric and Solar-Terrestrial Physics, 2012, 90-91: 172-178.

DOI：10.1016/j.jastp.2012.04.007

• Sporadic E
• Planetary waves
• Tidal waves
• Mid-latitude ionosphere

The present study mainly concerns the wave-like activity in the ionospheric sporadic E layer (Es) and in the lower lying stratosphere. The proposed analysis involves parameters describing the state of plasma in the sporadic E layer. Critical frequencies foEs and layer heights hEs were measured at the Pruhonice station (50 degrees N, 14.5 degrees E) during summer campaigns 2004, 2006 and 2008. Further, we use neutral atmosphere (temperature data at 10 hPa) data from the same time interval. The analysis concentrates on vertically propagating wave-like structures within distant atmospheric regions. By means of continuous wavelet transform (CWT) we have detected significant wave-like oscillation at periods covering tidal and planetary oscillation domains both in the Es layer parameters (some of them were reported earlier, for instance in works of Abdu et al., 2003: Pancheva and Mitchel, 2004; Pancheva et al., 2003; Sauli and Bourdillon, 2008) and in stratospheric temperature variations. Further analyses using cross wavelet transform (XWT) and wavelet coherence analysis (WTC) show that despite high wavelike activity in a wide period range, there are only limited coherent wave-like bursts present in both spectra. Such common coherent wave bursts occur on periods close to eigen-periods of the terrestrial atmosphere. We suppose that vertical coupling between atmospheric regions realized by vertically propagating planetary waves occurs predominantly on periods close to those of Rossby modes. Analysis of the phase shift between data from distant atmospheric regions reveals high variability and very likely supports the non-linear scenario of the vertical coupling provided by planetary waves.

• 出版日期2012-12