Seasonal variations in the horizontal wind structure from 0-100 km above Rothera station, Antarctica (67° S, 68° W)

[摘要] A medium frequency spaced-antenna radar has been operating at Rotherastation, Antarctica (67° S, 68° W) for two periods, between 1997-1998and since 2002, measuring winds in the mesosphere and lower thermosphere. Inthis paper monthly mean winds are derived and presented along with three yearsof radiosonde balloon data for comparison with the HWM-93 model atmosphereand other high latitude southern hemisphere sites. The observed meridionalwinds are slightly more northwards than those predicted by the model above80 km in the winter months and below 80 km in summer. In addition, thealtitude of the summer time zero crossing of the zonal winds above thewestward jet is overestimated by the model by up to 8 km. These data arethen merged with the wind climatology obtained from falling spheremeasurements made during the PORTA campaign at Rothera in early 1998 and theHWM-93 model atmosphere to generate a complete zonal wind climatologybetween 0 and 100 km as a benchmark for future studies at Rothera. Awestwards (eastwards) maximum of 44 ms^-1 at 67 km altitude occurs inmid December (62 ms^-1 at 37 km in mid July). The 0 ms^-1 windcontour reaches a maximum altitude of 90 km in mid November and a minimumaltitude of 18 km in January extending into mid March at 75 km and earlyOctober at 76 km.

[学科分类] 大气科学