Using The Reanalysis Of Atmospheric Data To Calculate Grace Atmosphere De-aliasing Model

The calculation of high-precision and high-temporal-resolution earth gravity field model has always been one of the research hotspots in modern geodesy and related geosciences.As a dedicated gravity measurement satellite,GRACE data can be used to obtain high accuracy and resolution time-varying earth gravity field model.However,there is still a certain variability between the precision of the earth's gravity field model solved by the current GRACE satellite measured data and the accuracy of the simulation before the launch.This difference is affected by the observational noise,anisotropic space sampling,satellite gravity inversion method,and the influence of various reference force model noise.In addition,the atmospheric and ocean de-aliasing models are also important influencing factors.In this paper,we use reanalysis of atmospheric data,combined with a variety of atmospheric integration methods and spherical harmonic analysis methods,to calculate a variety of time from 2007.01.01 ~ 2007.12.31,interval of 6h,intercepted to 100 degree and order GRACE atmospheric de-aliasing model.The gaps between models are compared from various aspects.The relevant research contents and conclusions of the article are summarized as follows:(1)Describes the development of gravity satellites,explains the importance of GRACE atmospheric de-aliasing model,and introduces the research status at home and abroad.The reanalysis of the development and prediction model of atmospheric data is described in detail,and the ERA-Interim reanalysis data related model layer used in this paper is highlighted.The atmospheric integral method and the theory and method of spherical harmonic analysis for GRACE atmospheric de-aliasing model are described in detail,and the relevant intermediate calculation values are given.(2)For various GRACE atmospheric de-aliasing models that are calculated using different atmospheric integration methods,the gaps between models are compared from the spectral and spatial perspectives,and principal component analysis is used to compare long-term sequences between the models.Various comparison results show that the results of the four atmospheric integration methods are similar,but there is also a certain gap.These gaps are negligible for the calculation of the current GRACE time-varying gravity field.However,for the accuracy requirements of the next generation of gravity satellites,the gap between the atmospheric integration method and GRACE atmospheric de-aliasing model needs to be considered.(3)Based on the latest vertical integration method and non-smooth spherical harmonic analysis method,a new generation of GRACE atmospheric de-aliasing model RL06 is calculated and compared with the official RL05 model.Comparing the gaps between the two models from the spatial domain and the spectral domain,principal component analysis compares the long-term sequences of the two models.Various comparison results show that the signals of the two models are basically the same,which verifies the accuracy of this method to calculate the new generation GRACE atmospheric de-aliasing model RL06.At the same time,there is a certain gap between them.This paper briefly analyzes the causes of the gaps.The first is the difference in atmospheric data.The real-time atmospheric data used by the official RL05 model has suddenly jumped in 2006 and 2010,which has an impact on the quality of atmospheric data.And this effect was brought into the official RL05 model.The reanalysis data used in this method does not have a jump condition.The second is the effect of the vertical integration method and the spherical harmonic analysis method.The official RL05 model uses a three-dimensional integration method combined with the conventional trapezoidal spherical harmonic analysis.In this paper,the RL06 model is calculated using the RL06 integration method,combined with the non-smooth spherical integral method,the main feature of non-smooth spherical harmonic integral is the consideration of the abnormal discontinuity of surface pressure.These several reasons caused a slight gap between the two models.It is shown from the analysis that the gap between the two is negligible for the current GRACE time-varying gravity field calculation.However,to achieve the GRACE simulation accuracy and the accuracy of the next generation of gravity satellites,the gap between the two needs to be taken into account.