Abstract
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 in monthly mean temperatures and winds, which in 2012 are affected by a sudden stratospheric warming. The temporal evolution of winds and temperatures after that warming are studied over a period of 2 weeks, showing an elevated stratopause and the reformation of the polar vortex. The monthly mean temperatures and winds are compared to data extracted from the Integrated Forecast System of the European Centre for Medium-Range Weather Forecasts (ECMWF) and the Horizontal Wind Model (HWM07). Lidar and ECMWF data show good agreement of mean zonal and meridional winds below ≈ 55 km altitude, but we also find mean temperature, zonal wind, and meridional wind differences of up to 20 K, 20 m s−1, and 5 m s−1, respectively. Differences between lidar observations and HWM07 data are up to 30 m s−1. 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 3–10 above 50 km altitude. Similarly, we estimate the energy density per unit mass for large-scale waves (LWED) from the fluctuations of nightly mean temperatures and winds. The total LWED is roughly constant with altitude. The ratio of kinetic to potential LWED varies with altitude over 2 orders of magnitude. LWEDs from ECMWF data show results similar to the lidar data. From the comparison of GWED and LWED, it follows that large-scale waves carry about 2 to 5 times more energy than gravity waves.
Highlights
Winds in the middle atmosphere play an important role for atmospheric dynamics; e.g., filtering of gravity waves is controlled by the background wind field (e.g., Lindzen, 1981; Gill, 1982; Nappo, 2002)
The SDs of zonal and meridional wind data are of nearly the same size (±2 m s−1): at 50 km and 70 km altitude, respectively, they are 18 and 29 m s−1 in January 2012, 24 and 26 m s−1 in January 2014, and 20 and 30 m s−1 in January 2015
After this minor SSW, two phenomena that are commonly linked to major SSWs were observed by the Arctic Lidar Observatory for Middle Atmosphere Research (ALOMAR) RMR lidar: an elevated stratopause and the reformation of the polar vortex
Summary
Winds in the middle atmosphere play an important role for atmospheric dynamics; e.g., filtering of gravity waves is controlled by the background wind field (e.g., Lindzen, 1981; Gill, 1982; Nappo, 2002). We present horizontal winds and temperatures obtained by DoRIS, the Doppler Rayleigh Iodine Spectrometer of the ALOMAR RMR lidar, during the three January seasons of 2012, 2014, and 2015, in total more than 300 h of observations They provide the most extensive data set of simultaneous wind and temperature measurements in the middle atmosphere and allow us to study the interannual variability in temperatures and winds, the temporal evolution on timescales of days, e.g., after the stratospheric warming in January 2012, and during single nights. We extracted data on an hourly basis (corresponding to the temporal sampling of the lidar) for the location 69.3◦ N, 16.0◦ E
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