利用一维变分同化方法从地基GPS相位延迟中获取大气折射率

Using One-Dimensional Variational Assimilation Algorithm to Obtain Atmospheric Refractive Index from Ground-Based GPS Phase Delay

GPS信号相位延迟中包含很多大气信息,通过一定的方法可以从中获取有价值的大气参数。基于地基GPS相位延迟数据,提出了一种结合经验模式的一维变分同化获取大气折射率的方法。利用GPS相位延迟模拟数据进行同化试验,讨论了背景误差的设置对同化结果的影响,采用实测个例对该方法进行了验证。结果表明,该一维变分同化方法可行,并可获取高精度的0～60 km大气折射率。低层大气背景误差设置的准确程度会对整个高度范围内的同化效果产生影响。首次将同化获取的大气折射率应用于无线电波折射修正,取得了很好的修正效果,修正精度可达1 mm量级。

GPS phase delay contains a lot of information that can be used to obtain atmospheric parameters with certain methods. Based on ground-based GPS phase delay,a one-dimensional variational（ 1DVAR） assimilation algorithm combined with an empirical model is proposed to obtain the atmospheric refractive index.The assimilation experiment is carried out by using simulated GPS phase delay data,and also verified with actual measured data. The influence of the background error settings on the result of assimilation is discussed.The experimental result shows that the 1DVAR assimilation algorithm can get high-precision atmospheric refractive index in 0-60 km height. The background error settings of the lower layers can affect the assimilation result in the whole height range. The atmospheric refractive index obtained from the assimilation experiment is used to correct the radio wave refraction,and the result is very good,which can reach 1 mm scale correction accuracy.