Determining the origin of tidal oscillations in the ionospheric transition region with EISCAT radar and global simulation data

Günzkofer, F.; Pokhotelov, D.; Stober, G.; Liu, H.; Liu, H.‐L.; Mitchell, N.J.; Tjulin, A.; Borries, C.. 2022 Determining the origin of tidal oscillations in the ionospheric transition region with EISCAT radar and global simulation data. Journal of Geophysical Research: Space Physics, 127 (10). 17, pp. https://doi.org/10.1029/2022JA030861

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Official URL: https://agupubs.onlinelibrary.wiley.com/doi/10.102...

Abstract/Summary

At high-latitudes, diurnal and semidiurnal variations of temperature and neutral wind velocity can originate both in the lower atmosphere (UV or infrared absorption) or in the thermosphere-ionosphere (ion convection, EUV absorption). Determining the relative impact of different forcing mechanisms gives insight to the vertical coupling in the ionosphere. We analyse measurements from the incoherent scatter radar (ISR) facility operated by the EISCAT Scientific Association. They are complemented by meteor radar data and compared to global circulation models. The amplitudes and phases of tidal oscillations are determined by an Adaptive Spectral Filter (ASF). Measurements indicate the existence of strong semidiurnal oscillations in a two-band structure at altitudes ≲ 110 km and ≳ 130 km, respectively. Analysis of several model runs with different input settings suggest the upper band to be forced in situ while the lower band corresponds to upward-propagating tides from the lower atmosphere. This indicates the existence of an unexpectedly strong, in situ forcing mechanism for semidiurnal oscillations in the high-latitude thermosphere. It is shown that the actual transition of tides in the altitude region between 90 and 150 km is more complex than described so far.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1029/2022JA030861
ISSN:	2169-9380
Date made live:	06 Oct 2022 14:32 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/533267

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1029/2022JA030861

ISSN:

2169-9380

Date made live:

06 Oct 2022 14:32 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/533267