Combined measurements with the EISCAT radar and the Nordic Meteor Radar Cluster to determine AGW-TID wave parameters
- 1Institute for Solar-Terrestrial Physics, German Aerospace Center (DLR), Neustrelitz, Germany
- 2formerly at Institute for Solar-Terrestrial Physics, German Aerospace Center (DLR), Neustrelitz, Germany
- 3Institute of Applied Physics & Oeschger Center for Climate Change Research, Microwave Physics, University of Bern, Bern, Switzerland
- 4Institute of Physics and Technology, UiT, Arctic University of Norway, Tromsø, Norway
- 5North West Research Associates, Boulder, Colorado, USA
- 6EISCAT Scientific Association, Kiruna, Sweden
- 7Tromsø Geophysical Observatory, UiT, Arctic University of Norway, Tromsø, Norway
- 8Swedish Institute of Space Physics (IRF), Kiruna, Sweden
- 9Sodankylä Geophysical Observatory, University of Oulu, Oulu, Finland
- 10Department of Physics and Astronomy, University of Leicester, Leicester, UK
- 11British Antarctic Survey, Cambridge, UK
- 12Department of Electronic & Electrical Engineering, University of Bath, Bath, UK
- 13Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan
- 14National Institute of Polar Research, Tachikawa, Japan
- 15The Graduate University for Advanced Studies (SOKENDAI), Tokyo, Japan
Atmospheric Gravity Waves (AGWs) forced in the lower atmosphere are known to have a significant impact on the mesosphere and lower thermosphere (MLT) region. In the ionosphere, they can generate Medium-Scale Traveling Ionospheric Disturbances (MSTIDs). These disturbances roughly occur on time scales of 15−80 min and are therefore often parametrized rather than directly resolved in ionosphere models. The energy and momentum transport by AGW-TIDs strongly depends on their wave parameters. Measurements of AGW-TIDs in the MLT region and determination of the wave parameters (vertical and horizontal wavelength, wave period and propagation direction) are therefore an essential step to improve ionosphere modelling. However, measurements that provide a good resolution in the vertical dimension (≲ 10 km) and time (≲ 10 min) as well as a large enough coverage in the horizontal dimension (≳ 300 × 300 km) are difficult at MLT altitudes. We show, that combined measurements of the EISCAT VHF incoherent scatter radar and the Nordic Meteor Radar Cluster allow to determine the wave parameters of AGW-TIDs across the whole MLT region. Fourier filter methods are used to separate wave modes by wavelength, period and propagation direction. The extracted wave modes are fitted with wave functions in time-altitude and horizontal cross sections which gives the wave parameters. The coverage regions of the two applied instruments are separated only by approximately 10 km in altitude, which allows to identify a single wave mode in both measurements. We present the developed techniques on the example of a strongly pronounced AGW-TID measured on July 7, 2020. As a first application, two measurement campaigns have been conducted in early September and mid-October 2022 to study possible changes in AGW-TID parameters due to the MLT fall transition occurring around equinox. Another possible application of our method is to infer thermospheric neutral winds from the observed waves. We demonstrate this process under the assumption of the anelastic dissipative gravity wave dispersion relation.
How to cite: Günzkofer, F., Pokhotelov, D., Stober, G., Mann, I., Vadas, S. L., Becker, E., Tjulin, A., Gulbrandsen, N., Kero, J., Kozlovsky, A., Lester, M., Mitchell, N., Nozawa, S., Tsutsumi, M., and Borries, C.: Combined measurements with the EISCAT radar and the Nordic Meteor Radar Cluster to determine AGW-TID wave parameters, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-9189, https://doi.org/10.5194/egusphere-egu23-9189, 2023.
