Fwd: VERSIM/GEM Journal Club Invitation

[Jonathan]

---------- Forwarded message ---------
From: František Němec <frantis...@matfyz.cuni.cz>
Date: Mon, Mar 30, 2026 at 7:32 AM
Subject: VERSIM/GEM Journal Club Invitation
To:

Hello everyone, 

It's almost time for the April session of the VERSIM/GEM Journal Club! This month we have Dr Siva Mani from the Leibniz Institute of Atmospheric Physics (IAP) presenting his work from a recent paper using ground-based measurements to investigate ionospheric oscillations (https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024JA033604).  

The abstract and the Zoom link are provided below. More details about the journal club can be found here: https://aurora.troja.mff.cuni.cz/versim/index_jc.html  

 

We hope to see many of you there!

 

Best wishes, 

Rachel, Mirek, Jodie, Harriet, Yang and Suhail

 

Date and time: 1^st April @ 9am PDT / 12pm EDT / 4pm UTC / 5pm BST / 6pm CEST 

 

Zoom link: https://universityofexeter.zoom.us/j/94859939623?pwd=MWtlb3K4pwAdb5qA5TaL2tJlFfSaPb.1

Speaker: Dr Siva Mani, Leibniz Institute of Atmospheric Physics (IAP)

Title: Interannual Oscillations and residual trends in the F, E, and D Region Ionosphere Using Longterm Ground‐Based Measurements 

Abstract: The middle and upper atmosphere act as early indicators of anthropogenic impacts on the atmosphere. However, compared with other dynamical and solar forcing effects, anthropogenic influences are relatively minor. Therefore, to quantify these effects, it is essential to first understand the natural variability that drives changes in observational parameters. In this context, this study focuses on the identification of interannual oscillations and the estimation of residual long-term trends in the ionosphere.

This comprehensive study investigates interannual oscillations with periods ranging from 1 to 25 years in the F, E, and D region ionosphere. To achieve this, we use long-term (1960–2018) continuous ground-based observational datasets obtained from an ionosonde operating at Juliusruh in northern Germany and standard phase height measurements from Kühlungsborn, Germany. Both instruments have been operational for more than sixty years, providing one of the longest continuous datasets available for ionospheric studies.

Using these datasets, we identify the dominant periodicities and their temporal variability by applying advanced spectral analysis techniques, including the Lomb–Scargle periodogram, wavelet analysis, and coherence analysis to detrended and deseasonalized data. In addition, our investigation includes a detailed analysis of solar proxies, specifically the F10.7 cm radio flux and Lyman-α (Ly-α) radiation, to better understand the potential solar drivers and underlying physical mechanisms responsible for these oscillations.

The long-term trends are estimated by applying a least-squares regression to the residual time series obtained after subtracting the modeled components from the observations.

Associated paper: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024JA033604