实时格网对流层模型在中国区域的适用性分析

利用无线电探空数据,对格网对流层模型GPT2w、IGGtrop及GTPs在中国区域的适用性进行分析。结果显示,GPT2w和IGGtrop在地表附近精度相当,RMS为4.0～4.2 cm,西部地区精度优于东部,东南沿海精度最差,夏季精度明显低于冬季,在中西部地区分辨率低的模型可能会产生异常偏差;GPT2w模型明显存在系统性偏差,中西部为正,东南部为负;3 km高度以上,IGGtrop模型精度明显优于GPT2w模型,且随高度增加精度保持稳定。在飞行器定位导航中,建议采用IGGtrop模型修正ZTD误差。GTPs模型时间分辨率高,精度明显优于传统的经验模型,尤其在东南沿海ZTD变化剧烈的区域,但由于其依赖于外部数据源,部分区域无法使用。

Applicability Analysis of Real Time Grid Tropospheric Models over China

Tropospheric delay is one of the main errors in space geodetic techniques, and it must be correctly mitigated. In this paper, the radiosonde data are used to analyze the applicability of the grid tropospheric models GPT2w, IGGtrop, and GTPs in China. The results show that the GPT2w model and the IGGtrop model have accuracy of about 4.0-4.2 cm near the ground. The models’ performance in the western region is better than that in the eastern region, and the worst accuracy is found in the southeast. The accuracy in summer is obviously lower than that in winter. The GPT2w model version with lower spatial resolution may produce abnormal deviations in the middle and western regions. The GPT2w model clearly has systematic deviations, positive in the middle and western parts and negative in the southeast part. The accuracy of IGGtrop model is much higher than GPT2w model at heights above 3 km and remains stable with the increasing height. In addition, IGGtrop model is recommended to correct ZTD errors in aircraft positioning navigation. The temporal resolution of GTPs model is higher than empirical models, which results in higher accuracy, especially for the southeast region with variable humidity. However, it is unable to apply GTPs model in some areas due to insufficient GNSS data, which are used to update GTPs model. By analyzing the accuracy of different tropospheric models in China, this study provides a reference for users in China region.