A comparison of 11-year mesospheric and lower thermospheric winds determined by meteor and MF radar at 69 ° N

Abstract

Abstract. The Andenes Meteor Radar (MR) and the Saura Medium Frequency (MF) Radar are located in northern Norway (69 • N, 16 • E) and operate continuously to provide wind measurements of the mesosphere and lower thermosphere (MLT) region. We compare the two systems to find potential biases between the radars and combine the data from both systems to enhance altitudinal coverage between 60 and 110 km. The systems have altitudinal overlap between 78 and 100 km at which we compare winds and tides on the basis of hourly winds with 2 km altitude bins. Our results indicate reasonable agreement for the zonal and meridional wind components between 78 and 92 km. An exception to this is the altitude range below 84 km during the summer, at which the correlation decreases. We also compare semidiurnal and diurnal tides according to their amplitudes and phases with good agreement below 90 km for the diurnal and below 96 km for the semidiurnal tides.Based on these findings we have taken the MR data as a reference. By comparing the MF and MR winds within the overlapping region, we have empirically estimated correction factors to be applied to the MF winds. Existing gaps in that data set will be filled with weighted MF data. This weighting is done due to underestimated wind values of the MF compared to the MR, and the resulting correction factors fit to a polynomial function of second degree within the overlapping area. We are therefore able to construct a consistent and homogenous wind from approximately 60 to 110 km.

Middle‐ and High‐Latitude Mesosphere and Lower Thermosphere Mean Winds and Tides in Response to Strong Polar‐Night Jet Oscillations

“…The specular meteor radars (SMRs) located at the sites of Andenes (69.3 • N, 16 • E) and Juliusruh (54.6 • N, 13.3 • E) have been extensively used to study neutral winds and atmospheric waves in the MLT region (e.g., Chau et al, 2015;Hoffmann et al, 2007Hoffmann et al, , 2010Conte et al, 2017Conte et al, , 2018Wilhelm et al, 2017). Combined, they provide continuous measurements for a set that is currently comprised of more than 15 years worth of data.…”

Trends and Variability in Vertical Winds in the Southern Hemisphere Summer Polar Mesosphere and Lower Thermosphere

“…By using the methodology of Dowdy et al () it is possible to extend this study to measurements of vertical winds in the summertime MLT. However, MFR observations can underestimate the magnitude of the wind motions, as discussed by Wilhelm et al () and Reid et al (). Wind measurements with a colocated meteor wind radar are used to calibrate the MFR observations.…”

“…Since the method for determining vertical winds requires accurate estimates of (equation ) there was a need to correct the MFR wind speeds. This was achieved by intercomparing the MFR wind components against simultaneous measurements made with a colocated 33‐MHz meteor wind radar (see Reid et al, ), so the MFR wind speeds can be corrected, as recently discussed by Wilhelm et al () and Reid et al (). A similar approach to that used by Reid et al () is adopted here to estimate the biases with height in the MFR wind components using the MWR data that are available from 2005 to 2018.…”

Intercomparison of middle-atmospheric wind in observations and models

“…These should appear as constant offsets to the measurements at a particular latitude. Especially the effect of the diurnal tide, which appears to be the strongest tidal component in the middle atmosphere, is strongly reduced by the averaging over the measurements during the satellite's overpasses in the ascending and descending orbit spaced by 12 h. A more detailed discussion on the impact of tides on MLS measurements can be found for example in Lieberman et al (2015) and Xu et al (2009). It should also be remembered that, in contrast to the mesopause region, tides are usually weak in the stratosphere and lower mesosphere (e.g.…”