一种新的区域对流层天顶延迟模型——Ghop

GHop: A New Regional Tropospheric Zenith Delay Model

  • 摘要: 针对传统的对流层天顶延迟模型在估算天顶延迟中存在精度不高和稳定性差的问题,提出了一种在Hopfield模型基础上增加年周期和半年周期项的方法。该方法利用中国区域45个站2012-2014年的全球大地测量观测系统大气数据,分析了天顶对流层延迟以及Hopfield模型残差的时间序列和频谱分布规律,由此引入年周期和半年周期项,建立了适应中国区域的GHop模型,并对两种模型在中国区域的精度和适应情况进行了评估。结果表明:Hopfield模型的偏差和均方根在时间上呈现明显的季节变化特征,而GHop模型的偏差和均方根变化较小且稳定;在空间分布上,Hopfield模型随着高程和纬度增加,偏差和均方根变化幅度大,而GHop模型能够适应不同纬度和高程的变化范围;GHop模型的内符合精度较Hopfield模型提高28%,使用中国区域76个无线电探空数据进行外符合检验,统计结果同样优于Hopfield模型。所提方法计算的天顶对流层延迟结果更加可靠,具备较高的实用价值。

     

    Abstract: To solve the problems of low accuracy and poor stability in the traditional estimation of zenith delay, a method of adding annual and semi-annual periodic terms on the basis of Hopfield model is proposed. Based on the atmospheric data of the global geodetic observation system at 45 stations from 2012 to 2014 in China, the time series and spectrum distribution of zenith tropospheric delay (ZTD) and residual Hopfield model are analyzed. With the introduction of annual and semi-annual cycle term, the GHop model suitable for China region is established, and the accuracy and adaptation of the two models are evaluated. The results show that the deviation and middle error of Hopfield model represent obvious seasonal variation in time, while GHop model is small and stable. In terms of spatial distribution, the Hopfield model varies greatly with the increase of elevation and latitude, GHop model can adapt to different latitudes and elevation ranges. Annual deviation of coincidence accuracy in GHop is 28% higher than that of Hopfield, and 76 radiosensory data in China are used for external coincidence test. The statistical results are better than those of Hopfield model. The ZTD results calculated by the proposed method are more reliable and have high practical value.

     

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