VHF radar measurements of momentum flux using summer polar mesopause echoes

Abstract

We revisit previously unpublished analysis of observations of the dynamics of the mesopause region over the Norwegian Island of Andøya (69°N, 16°E) made during a 1-week period in summer 1987 during the Middle Atmosphere Cooperation-Summer in Northern Europe (MAC-SINE) campaign using the mobile SOUSY VHF (53.5 MHz) Doppler radar operating in a six-beam mode. We do this in the light of: (1) more recent developments in the measurement of the components of the density-normalized Reynolds stress tensor using meteor radars, and with medium-frequency partial reflection radars using the hybrid Doppler interferometric technique, and (2) satellite measurements of the absolute upward flux of horizontal momentum. We consider of the density-normalized total upward flux of horizontal momentum u ′ w ′ + v ′ w ′ for the 83-90 km height interval. Values of the component of the density-normalized flux for the 6 min to 12.8 h period range, after the tidal components have been removed, and the effects of the aspect sensitivity on the radar beam look directions have been accounted for vary between 5 m 2 s −2 below 86 km and 13 m 2 s −2 above 86 km. The major contribution is from the 6 to 12.8 h period range. The results of the analysis have implications for meteor radar estimates of momentum flux and also for Doppler radar measurements of the same term in the presence of aspect-sensitive scattering.

Special issue “Recent Advances in MST and EISCAT/Ionospheric Studies – Special Issue of the Joint MST15 and EISCAT18 Meetings, May 2017”

“…However, particle precipitation still affects PMSE when they both occur simultaneously. Reid et al (2018a) used PMSE echo data for the measurement of momentum flux and found reasonable results compared to previous studies with meteor radars and medium frequency (MF) radars. Belova et al (2018) conducted a case study of polar mesospheric winter echoes (PMWE) using the tristatic EISCAT radar.…”

A new dual-frequency stratospheric–tropospheric and meteor radar: system description and first results

“…θ E in Eq. ( 2) is the effective beam direction for the off-zenith beams, which should replace the apparent off-vertical angle θ A considering the influence of aspect sensitivity (Reid et al, 2018b).…”

A New Dual-Frequency Stratospheric Tropospheric / Meteor Radar: System Description and First Results

“…Here 𝑣 𝐸 , 𝑣 𝑊 , 𝑣 𝑁 , 𝑣 𝑆 represent the radial perturbation velocities in the east, west, north, south beams, and 𝑢 ′ , 𝑣 ′ , 𝑤 ′ refer to the fluctuating zonal, meridional, vertical winds, respectively. 𝜃 𝐸 in equation ( 2) is the effective beam direction for the off-zenith beams, which should replace the apparent off-vertical angle 𝜃 𝐴 considering the influence of aspect sensitivity (Reid et al, 2018b). As we have seen above, the mean winds evaluated assuming that the apparent and effective beam angles are the same are in excellent agreement with the radiosonde measurements in the present study, and with numerous other intercomparisons made with this ST radar type.…”