Meteor heights during the recent solar minimum

[摘要] Average meteor heights have been continuously observed using a SKiYMET VHFradar at Collm (51.3° N, 13.0° E) since late summer of2004. Initially, the daily mean meteor height was about 89.4 km. Since thattime, average meteor heights have decreased. This is consistent with earlierresults on middle atmosphere temperature change from the literature and fromearlier results of low-frequency reflection height changes measured atKühlungsborn and Collm. During the recent solar minimum 2008/2009 themeteor heights further decreased. Linear fitting of a trend and a solar cycleto the heights reveals a linear decrease of about −56 m year⁻¹ and asolar cycle effect of +450 m per 100 sfu. Assuming that meteor heights,on a long-term average, approximately refer to a level of constant pressure,this decrease can be converted to a mean middle atmosphere linear temperaturedecrease of −0.23 K year⁻¹ and a solar cycle effect of +1.8 K per100 sfu during the last decade, which is in the range of observed trendsreported in the literature.

[学科分类] 电子、光学、磁材料