大气再分析资料反演对流层延迟精度分析

Analysis of tropospheric delay accuracy in atmospheric reanalysis data inversion

针对传统对流层延迟模型在复杂山区大高差环境下误差过大的问题,该文对欧洲中期天气预报中心的ERA5大气再分析资料反演的天顶对流层延迟精度进行分析,其中ERA5ZTD由积分法+Saastamoinen模型求得。结果表明:以精密单点定位模糊度固定估计的ZTD为参考,ERA5ZTD平均偏差绝对值为3.8mm,总平均均方根误差为10.5mm。北半球夏季偏差与均方根误差最大,冬季最小,南半球反之。并址站间的日内变化趋势相同,与PPP-AR ZTD变化趋势符合性较好,且呈现明显的日内周期性变化。ERA5ZTD均方根误差由赤道向两极呈递减趋势,不同测站高程处ZTD精度与高程无明显关系,整体表现出较高精度。总体上,ERA5ZTD能够满足在复杂山区大高差环境下的对流层延迟误差要求,可作为数据源进行区域对流层建模。

To address the problem of large errors in traditional tropospheric delay models in complex mountainous environments with large altitude differences,this paper analyses the accuracy of the zenith tropospheric delay in the inversion of ERA5atmospheric reanalysis data from the European Centre for Medium-Range Weather Forecasts,where the ERA5 ZTD is derived from the integral method+Saastamoinen model.The results show that the mean deviation of the ERA5ZTD is 3.8mm in absolute value and the total mean root-mean-square error is 10.5mm,using the ZTD estimated with fixed precision single-point positioning ambiguity as a reference.The deviation and root-mean-square error are the largest in the northern hemisphere in summer and the smallest in winter,and vice versa in the southern hemisphere.The intra-day variation trend is the same between the parallel stations,which is in good agreement with the PPP-AR ZTD variation trend and shows a clear intra-day cyclic variation.Overall,the ERA5ZTD can meet the requirements for tropospheric delay errors in complex mountainous environments with large height differences,and can be used as a data source for regional tropospheric modelling.