A comparison between mesospheric wind measurements made near Christchurch (44°S, 173°E) using the high resolution doppler imager (HRDI) and a medium frequency (MF) radar

摘要

We report on the comparison of winds measuredby a medium frequency (MF) radar near Christchurch, New Zealand, and by the highresolution doppler imager (HRDI). Previous comparisons have demonstrated thatthere can be significant differences in the winds obtained by the twotechniques, and our results are no different. However, these data showrelatively good agreement in the meridional direction, but large differences inthe zonal direction, where the radar is regularly measuring the zonal wind astoo easterly. To do the comparison, overpasses from the satellite must beobtained when it is close to the radar site. The radar data are averaged in timearound the overpass because we know the radars sample phenomena which havespatial and temporal scales which make them invisible to HRDI. There are alimited number of overpass comparisons which limit our confidence in theseresults, but a detailed analysis of these data show that the proximity of theoverpass is often an important factor in the differences obtained. Other factorsexamined include the influence of the local time of the overpass, and the amountof radar data averaged around the overpass time.Key words: Atmospheric composition and structure(instruments and techniques) · Meteorology and atmospheric dynamics (middleatmosphere dynamics; instruments and techniques)