Tatiana V. Barlyaeva | Searcharxiv

arXiv2020

Variations of TEC over Iberian Peninsula in 2015 due to geomagnetic storms and solar flares

The total ionospheric content (TEC) over the Iberian Peninsula was studied using data from two locations obtained both by GNSS receivers and an ionosonde. The principal component analysis applied to the TEC data allowed us to extract two main modes. Each mode is characterized by daily TEC variation of a certain type (PC) and its amplitude for each of the studied day (given by the empirical orthogonal functions, EOF). The variations of these modes as well as the original TEC data were studied in relations to four strongest geomagnetic storms of 2015 and three geomagnetic disturbances of lower amplitude observed during the same months. EOFs were found to correlate well with space weather parameters characterizing solar UV and XR fluxes, number of the solar flares, parameters of the solar wind and geomagnetic indices. Multiple regression models were constructed to fit EOFs using combinations of the space weather parameters with a lag from 0 to 2 days. Combining the regression models of EOFs with the corresponding PCs we reconstructed TEC variations as a function of space weather parameters observed in previous days. The possibility to use such reconstructions for the TEC forecasting was also studied.

physics.geo-ph↗

arXiv2019

Temperature and pressure variability in mid-1 latitude low atmosphere and stratosphere-ionosphere coupling

This study presents the continuation of the analysis of variations of atmospheric and space weather parameters above Iberian Peninsula along two years near the 24th solar cycle maximum presented in Morozova et al. [2016]. Previously, the first mode of the principal component analysis was shown to correlate with the lower stratospheric ozone and anti-correlate with cosmic ray flux. In this paper we discuss the second mode that, to our mind, suggests a coupling between the stratosphere and ionosphere. This second mode, located in the low and middle stratosphere and explaining 6-15\% of temperature and 2.5\% of geopotential height variations, positively correlates with the middle-stratospheric ozone content. Among locally measured space weather parameters, this atmospheric mode negatively correlates with the ionospheric total electron content. The stratospheric-ionospheric coupling was analyzed using the correlation and wavelet analyses. Found similarities between variations of the stratospheric and ionospheric parameters were tested with a method allowing estimation of the causal nature of the found relationships, the convergent cross mapping (CCM). Strong evidences for the stratospheric-ionospheric coupling were obtained for the winter 2012-2013 that is characterized by the east QBO phase and a strong sudden stratospheric warming event.

physics.ao-ph↗