Observation of Gravity Waves at the Polar Night Jet

The polar night jet develops at high latitudes in the altitude range 30 to 70 km in winter time. The polar night jet (PNJ) shows the highest mean wind speeds observed in the atmosphere and likely plays an important role in multi-step vertical coupling not only from the ground, but also from the upper atmosphere downwards.PNJ not only controls the propagation and dissipation of gravity waves (GWs), it can also be a source of GWs due to spontaneous emission. However, the observations of interaction of GWs with PNJ are extremely difficult. We operate lidar instruments capable of measuring temperatures and winds above northern Norway (ALOMAR, 69°N) and northern Germany (Kühlungsborn, 54°N). The instruments observed the atmosphere inside and outside the Polar Vortex for more than 10 years. Using lidar measurements of temperatures and winds allows for studying up- and downward-propagating GWs in complicated dynamical situations that are often found at the polar vortex edge. Observing simultaneously up- and downward propagating waves may indicate gravity wave breakdown and secondary wave generation. We discuss the relationship between waves characteristics as observed by our lidar instruments and the polar vortex based on ECMWF data.
The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)