HAO Colloquium - Nikolay Zabotin, CU

Studies of Wave Activity in the Thermosphere-Ionosphere System Using Dynasonde Techniques

Dynasonde approach to ionospheric radio sounding capitalizes on high precision of physical parameters and rich statistics of recognized echoes phase-based methods can provide. As has been recently demonstrated, the Dynasonde profiles of the electron density and of the horizontal gradients, complemented with profiles of the Doppler speed, carry comprehensive quantitative information about Atmospheric Gravity Waves, a ubiquitous feature of the space weather that has become an important objective of atmospheric modeling. Being combined into a time series, and without additional processing, the profiles allow visualization of the time fronts of the Traveling Ionospheric Disturbances (TIDs). They also provide high-resolution input data for calculating the complete set of parameters (both vertical and horizontal) of TID activity in the upper atmosphere between the base of the E layer and the maximum of the F layer. Application of the Lomb-Scargle periodogram technique to the tilt data provides unique insight into the dynamics of spectral composition of the TIDs. A similar technique applied to longer time series allows determining characteristics of thermospheric tides. Single sounding sessions allow observations of ionospheric manifestations of acoustic waves produced by ground-based sources. All the mentioned products of the Dynasonde data analysis require a common, standard ionogram mode of radar operation. Therefore, information about standard parameters of the ionospheric E, F regions, possibility to obtain vector velocities characterizing movement of plasma contours, and quantitative parameters of the km-scale irregularity spectrum are not lost and contribute into comprehensive description of wave activity in the thermosphere-ionosphere system. In this presentation we will touch the following topics:

  • Comparison of TID parameters to the ones predicted by the gravity wave dispersion relation;
  • Typical properties of the spectra of thermospheric wave activity;
  • Ocean as a major source of the thermospheric waves;
  • Dynasonde measurements of the momentum deposition by the gravity waves;
  • Concurrent observations of TIDs at two close locations;
  • Measurements of tidal harmonics at thermospheric altitudes;
  • Some special cases of wave activity (solar terminator, eclipse, etc.).

Building:

Room Number: 
2126

Type of event:

Will this event be webcast to the public by NCAR|UCAR?: 
Calendar Timing: 
Wednesday, February 7, 2018 - 2:00pm to 3:00pm