EGU2020-8789
https://doi.org/10.5194/egusphere-egu2020-8789
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Lidar Observations of Seasonal Variability of Gravity-Waves

Irina Strelnikova, Gerd Baumgarten, and Franz-Josef Lübken
Irina Strelnikova et al.
  • Leibniz Institute of Atmospheric Physics, Optical Soundings and Sounding Rockets, Kühlungsborn, Germany

In order to understand the generation, propagation and climatology of gravity waves (GWs)observations with high temporal and vertical resolution are required. The observation of gravity waves is important to understand the vertical coupling in the atmosphere.

Recent developments in lidar technology give us new possibilities to study GWs experimentally on a more or less regular basis and resolve spatial sales of 150
meters in the vertical and temporal scales of about 10 minutes. In particular, the capability to operate the lidar during daytime allows for long duration GW observations. The Doppler Rayleigh Iodine Spectrometer (DoRIS) in additionto the established hydrostatic temperature measurement technique yields simultaneous and common volume measurements of winds.

At the ALOMAR observatory in northern Norway (69°N, 16°E)
the gravity wave potential energy density (GWPED) in the stratosphere is shown to have a large seasonal variation with a maximum in winter and a minimum in summer.

In this work we use the phase relation between both zonal and meridional wind components and temperature. We study gravity waves sorted for up- and downward propagating waves under summer and winter conditions to investigate different wave propagation and generation scenarios. We discuss the winter/summer difference not only in terms of total GWPED, but in terms of wave characteristics obtained from our extended analysis technique. We demonstrate, for example, that amount of downward propagating waves is larger in winter than in summer. Also, other wave characteristics like phase speed and mean intrinsic period
will be discussed.

How to cite: Strelnikova, I., Baumgarten, G., and Lübken, F.-J.: Lidar Observations of Seasonal Variability of Gravity-Waves, EGU General Assembly 2020, Online, 4–8 May 2020, https://doi.org/10.5194/egusphere-egu2020-8789, 2020

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Presentation version 1 – uploaded on 05 May 2020
  • CC1: Comment on EGU2020-8789, Paul Pukite, 15 May 2020

    The fact that semi-annual oscillations (SAO) are observed at the equator but not the poles makes sense, since at the polar latitudes (northern Norway is the focus of your study), a seasonal signal will be strongest, while the equator will show a semiannual oscillation for each nodal crossing.

    The lunar tidal nodal crossing will also amplify this, leading to the 28 month QBO cycles, but only SAO are observed at higher altitudes, where the atmosphere is thinner.