B. Andonov

Planetary waves in coupling the stratosphere and mesosphere during the major stratospheric warming in 2003/2004

[1] The vertical coupling of the stratosphere-mesosphere system through quasi-stationary and traveling planetary waves during the major sudden stratospheric warming (SSW) in the Arctic winter of 2003/2004 has been studied using three types of data. The UK Met Office (UKMO) assimilated data set was used to examine the features of the global-scale planetary disturbances present in the winter stratosphere of the Northern Hemisphere. Sounding the Atmosphere using Broadband Emission Radiometry (SABER) satellite measurements were used as well for extracting the stationary planetary waves in the zonal and meridional winds of the stratosphere and mesosphere. Radar measurements at eight stations, four of them situated at high latitudes (63–69N) and the other four at midlatitudes (52–55N) were used to determine planetary waves in the mesosphere-lower thermosphere (MLT). The basic results show that prior to the SSW, the stratospheremesosphere system was dominated by an upward and westward propagating � 16-day wave detected simultaneously in the UKMO and MLT zonal and meridional wind data. After the onset of the SSW, longer-period (� 22–24 days) oscillations were observed in the zonal and meridional MLT winds. These likely include the upward propagation of stationary planetary waves from below and in situ generation of disturbances by the dissipation and breaking of gravity waves filtered by stratospheric winds. Citation: Pancheva, D., et al. (2008), Planetary waves in coupling the stratosphere and mesosphere during the major stratospheric warming in 2003/2004, J. Geophys. Res., 113, D12105, doi:10.1029/2007JD009011.

Modeling the ionospheric parameters influence on the geomagnetic pulsation polarization: ULF magnetic field

The influence of the ionospheric parameters on the polarization characteristics of magnetosonic or ULF compressional wave disturbances is modeled. The parameters that have a significant impact on the polarization signature of the ULF compressional disturbances are the maximum height (hmE) and maximum concentration (NmE) of the E-region. The polarization rotation angle lies in the interval 0–90° for every critical frequency f0E (in MHz), but its magnitude is controlled by the maximum height hmE. For low maximum heights and higher critical frequencies (f0E) determined by the maximum concentration , the rotation angle is nearly 90°. For high maximum heights and a lower critical frequency (f0E<2), the rotation angle reduces to zero. The second effect, the ellipticity of the ULF wave disturbance, also varies in a wide interval, from a linear (the ellipticity effect is zero) to circular (the ellipticity is 1), depending on the E-regions maximum height (hmE). It is shown that the ellipticity effect has a maximum value for only a certain combination of f0E and hmE. The F-region ionization does not contribute essentially to the ionospheric effects on the ULF disturbance penetrations.