A long-term comparison of wind and tide measurements in the upper mesosphere recorded with an imaging Doppler interferometer and SuperDARN radar at Halley, Antarctica

Abstract

Abstract. Data from a near co-located imaging Doppler interferometer (IDI) and SuperDARN radar recorded since 1996 have been analysed in a consistent manner to compare the derived mean winds and tides in the upper mesosphere. By comparing only days when both techniques were recording good quality meridional wind data it is shown that the SuperDARN radar winds and tides correlate best with the IDI height bin 90-95 km. On timescales of one hour the winds derived from the IDI have a much greater associated variance and correlate poorly with the SuperDARN winds. Regression analysis reveals that the observed SuperDARN daily mean meridional wind strength is approximately 65% that recorded by the IDI, in good quantitative agreement with previous studies which have shown contamination to Super-DARN derived winds due to the significant back lobe of the radar radiation pattern. Climatologically the two techniques observe similar monthly mean winds with the Super-DARN meridional winds suppressed compared to the IDI which tends to record winds more poleward than those derived by the SuperDARN radar during the summer months, and to be slightly more equatorward during the winter. The 12-h tidal amplitude and phase derived from both techniques are in good agreement, whereas the 24-h tides are seen much more strongly in the SuperDARN radar, especially in wintertime, with poor phase agreement. Long term comparison of the two techniques reveals a tendency for the IDI meridional winds to be more poleward during solar maximum especially during summer time; an effect which is not reproduced in the meridional winds derived from the SuperDARN radar. These results are discussed in the context of previous studies to independently determine the veracity of each technique, and to highlight the circumstances where data derived Correspondence to: R. E. Hibbins (rehi@bas.ac.uk) from these two techniques can be used to draw reliable conclusions from comparative studies based on geographically distributed pairs of instruments.

Interannual variability of the S=1 and S=2 components of the semidiurnal tide in the Antarctic MLT

“…An hourly fit was only attempted if echoes were recorded in at least 5 out of 16 different radar beams. Hibbins and Jarvis (2008) have shown that the mean winds and semidiurnal tide observed from the Halley SuperDARN radar data are in excellent agreement with the data recorded in the 90-95 km height bin of a co-located imaging Doppler interferometer (Jones et al, 1997;Hibbins et al, 2006). The mean location of the scattering points used in determining the SuperDARN winds is 781S, 241W which is at exactly the same latitude as the Scott Base MF radar.…”

Long-term observations of the wind field in the Antarctic and Arctic mesosphere and lower-thermosphere at conjugate latitudes

“…This enhancement of the semidiurnal tide was also observed with an MF radar at a lower latitude at McMurdo (78°S, 167°W) [Fritts et al, 1998;Riggin et al, 1999]. By combining wind measurements with an MF radar at Scott Base and an Imaging Doppler interferometer (IDI) [Hibbins et al, 2006] and SuperDARN at Halley (76°S, 26°W) [Hibbins and Jarvis, 2008], Baumgaertner et al [2006] and Hibbins et al [2010aHibbins et al [ , 2010b confirmed that a summer enhancement of the SW1 mode is also observed at these latitudes. From comparisons of the semidiurnal tidal measurements at Scott Base, Molodezhnaya, and Mawson with those at South Pole, Portnyagin et al [1998] suggested that the SW1 mode dominates the semidiurnal tidal response from South Pole to ∼78°S, but that the semidiurnal tide is a mixture of the SW1 and SW2 modes at ∼68°S.…”

Nonmigrating semidiurnal tide over the Arctic determined from TIMED Doppler Interferometer wind observations

“…[36] Additionally, effects of interannual variations in the nonmigrating semidiurnal tide at high latitudes noted by Baumgaertner et al [2006], Hibbins and Jarvis [2007], Portnyagin et al [1998], and Riggin et al [1999] need to be considered in comparing measurements and model predictions. The seasonal structures of the nonmigrating semidiurnal tidal modes presented here are obtained as means of the 5 year measurements from 2002 to 2007.…”