Bevis公式在不同高度面的适用性以及基于近地大气温度的全球加权平均温度模型

Applicability of Bevis formula at different height level and global weighted mean temperature model based on near-earth atmospheric temperature

加权平均温度(T_m)是全球卫星导航系统(GNSS)反演可降水量(PWV)过程中的关键参量。利用Bevis公式和地表温度可以方便地得到地表附近的高精度T_m估计值。然而,不少研究指出,Bevis公式在高海拔地区存在较大误差。本文对Bevis公式在不同高度面的适用性进行研究后发现,Bevis公式在海拔较低时精度较高,随着海拔升高,精度逐渐降低。为了解决Bevis公式在高海拔地区适用性较低的问题,本文对近地空间范围内(本文指0～10 km的高程范围)的T_m与大气温度的关系展开了研究,发现两者在全球范围内都拥有很高的相关性,由此本文构建了基于近地大气温度的全球加权平均温度模型。对模型的检验结果表明,该模型在近地空间范围内的任意高度面上都可以提供高精度的T_m估计值。

Weighted mean temperature is a critical parameter in GNSS technology to retrieve precipitable water vapor(PWV). It is convenient to obtain high-accuracy T_m estimation near surface utilizing Bevis formula and surface temperature. However, some researches pointed out that the Bevis formula has large uncertainties in high-altitude regions. This paper researches the applicability of Bevis formula at different height levels and finds that the Bevis formula has relatively high precision when the altitude is low, while with altitude increasing, the precision decreases gradually. To solve the problem, this paper studies the relationship between T_m and atmospheric temperature of the near-earth space range(the height range between 0~10 km) and finds that they have high correlation on a global scale. Accordingly, this paper builds a global weighted mean temperature model based on near-earth atmospheric temperature. Validation results of the model show that this model can provide high-accuracy T_m estimation at any height level in the near-earth space range.