Validation of wind measurements of two mesosphere–stratosphere–troposphere radars in northern Sweden and in Antarctica
Abstract. Two atmospheric VHF radars: ESRAD (Esrange MST radar) located near Kiruna in
the Swedish Arctic and MARA (Moveable Atmospheric Radar for Antarctica) at the Indian research station Maitri in
Antarctica perform wind measurements in the troposphere and lower
stratosphere on a regular basis. We compared horizontal winds at altitudes
between about 0.5 and 14 km derived from the radar data using the full
correlation analysis (FCA) technique with radiosonde observations and
models. The comparison with 28 radiosondes launched from January 2017 to
August 2019 showed that ESRAD underestimates the zonal and meridional winds
by about 8 % and 25 %, respectively. This is likely caused by the
receiver group arrangement used for the FCA together with a high level of
non-white noise. A similar result was found when comparing with the regional
numerical weather prediction model HARMONIE-AROME (Bengtsson et al., 2017) for the period September 2018–May 2019. The MARA
winds were compared with winds from radiosondes for the period February–October 2014 (291 occasions). In contrast to ESRAD, there is no indication
that MARA underestimates the winds compared to the sondes. The mean
difference between the radar and radiosonde winds is close to zero for both
zonal and meridional components. The comparison of MARA with the ECMWF ERA5
reanalysis for January–December 2019 reveals good agreement with the mean
difference between 0.1 and − 0.5 m/s depending on the component and
season. The random errors in the wind components (standard deviations over
all estimates in 1 h averages) are typically 2–3 m/s for both radars.
Standard deviation of the differences between radars and sondes are 3–5 m/s.