基于全天空F-P干涉仪反演热层垂直中性风

A method for vertical neutral wind in the thermosphere deduced from all-sky FPI measurements

由于测量与计算的难度,对热层垂直中性风的观测还很不够,这影响了人们对热层及热层-电离层耦合的认识.本文基于全天空法布里-珀罗干涉仪(FPI)对热层风场的观测,提出了一种反演垂直中性风的方法.利用该方法,对北极黄河站全天空FPI观测数据进行了垂直中性风的反演计算,结果表明,高热层与低热层的垂直风平均幅值分别在40m·s-1和15m·s-1,且垂直风日变化表现出明显的时间演变特性,且与地磁ap指数的变化有一定的相关性,在地磁活动强烈时,低热层垂直风会出现高达100m·s-1的扰动,高热层甚至会达到300m·s-1的扰动,这些特征与其他学者的观测结果相一致.本文方法不需要假设垂直风均值为零,也不用限制FPI的观测方位,可用于垂直风的反演.

The difficulty in the measurement and/or calculation of the vertical neutral wind impedes the understanding of the thermosphere and the coupling of thermosphere-ionosphere. In this paper we develop a method to deduce the vertical neutral wind from the fringes obtained by one all-sky FPI. In particular, using this method, we obtain the vertical neutral wind above the Chinese Yellow River station. It shows that the average amplitude of vertical winds in the upper and lower thermosphere is 40 m. s-1 and 15 m . s-1. There are many short-term fluctuations of the vertical winds. The diurnal variation of vertical winds is likely associated with the ap index. The vertical winds in excess of 100 m . s-1 and 300 m .s-1 are observed in the lower and upper thermosphere on the most active day. These inferred characteristics of the vertical neutral wind are similar to those reported by other researchers, suggesting the reliability of our method.