Evidence for dynamical coupling from the lower atmosphere to the thermosphere during a major stratospheric warming

We used temperature data from the Michelson Interferometer for Passive Atmospheric Sounding on board ESA's Envisat satellite to analyze the temperature responses in the mesosphere and thermosphere up to 170 km to a major stratospheric sudden warming (SSW) which occurred in January 2009. The temperature observations show clear signatures of a mesospheric cooling and a thermospheric warming, the latter peaking at 120–140 km in agreement with model predictions. From the analysis of the zonal temperature structure during the SSW a pronounced wave 1 pattern was found in the entire middle and upper polar atmosphere with maximum amplitudes around 50 and 140 km. In the mesosphere, the wave amplitude is significantly damped. The wave amplification above is most likely produced by in situ forced planetary waves in the mesosphere and lower thermosphere region. Our observations represent the first experimental evidence of a dynamical coupling of the lower atmosphere and the thermosphere in the 120–150 km range by means of satellite data.