edu.ucar.opensky::articles:25780 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-24T20:00:52.772817 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7nv9p27 https://doi.org/10.5281/zenodo.6817130 https Related Dataset #1 [Dataset] Determining the origin of tidal oscillations in the ionospheric transition region with EISCAT radar and global simulation data https://doi.org/10.5281/zenodo.7072141 https Related Software #1 Determining the origin of tidal oscillations in the ionospheric transition region with EISCAT radar and global simulation data Determining the origin of tidal oscillations in the ionospheric transition region with EISCAT radar and global simulation data 2022-10-30T00:00:00Z publication https://n2t.org/ark:/85065/d7nv9p27 https://doi.org/10.1029/2022JA030861 Günzkofer, F. author Pokhotelov, D. author Stober, G. author Liu, H. author Liu, Hanli author Mitchell, N. author Tjulin, A. author Borries, C. author UCAR/NCAR - Library publisher At high-latitudes, diurnal and semidiurnal variations of temperature and neutral wind velocity can originate both in the lower atmosphere (UV or infrared absorption) and 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 analyze 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 less than or similar to 110 and greater than or similar to 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. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. None eng geoscientificInformation