Winds and temperatures of the Arctic middle atmosphere during
January measured by Doppler lidar
Abstract. We present an extensive data set of simultaneous temperature and wind measurements in the Arctic middle atmosphere. It consists of more than 300 h of Doppler Rayleigh lidar observations obtained during three January seasons 2012, 2014, and 2015, and covers the altitude range from 30 km up to about 85 km. The data set reveals large year-to-year variations of month-mean temperatures and winds, which in 2012 are caused by a sudden stratospheric warming. The temporal evolution of winds and temperatures after that warming are studied over a period of two weeks, showing an elevated stratopause and the reformation of the polar vortex. The month-mean temperatures and winds are compared to data extracted from the Integrated Forecast System of the European Centre for Medium-Range Weather Forecast (ECMWF) and the Horizontal Wind Model (HWM07). We find mean temperature, zonal wind, and meridional wind differences of up to 20 K, 20 m s−1, and 5 m s−1, respectively, between lidar observations and ECMWF data and of up to 30 m s−1 between lidar observations and HWM07 data. From the fluctuations of temperatures and winds within single nights we extract the potential and kinetic gravity wave energy density (GWED) per unit mass. It shows that the kinetic GWED is typically 5 to 10 times larger than the potential GWED, the total GWED increases with altitude with a scale height of ≈ 16 km. Since temporal fluctuations of winds and temperatures are underestimated in ECMWF, the total GWED is underestimated as well by a factor of 3 to 10 above 50 km altitude. Similarly we estimate the energy density per unit mass for large-scale waves LWED) from the fluctuations of night-mean temperatures and winds. The total LWED. The ratio of kinetic to potential LWED varies with altitude over two orders of magnitude. LWEDs from ECWMF data show similar results as the lidar data. From the comparison of GWED and LWED follows that large-scale waves carry about 2 to 6 times more energy than gravity waves.