Computation and Assessment Concerning Atmospheric Dealiasing Models Using CRA-40 Reanalysis Dataset

Objectives: Atmospheric and oceanic non-tidal high-frequency mass variations constitute a primary source of error that need to be accurately modeled and removed before the process of time-variable gravity field inversion. The advancement of China's gravity satellite mission makes achieving the domestic production of the background force model for the earth's gravity field highly meaningful. Methods: CRA-40 is China's first generation of reanalysis products. The evaluation of surface pressure and temperature illustrates that its quality is comparable to the third generation of global reanalysis on the basis of the comparisons we perform. A set of atmospheric dealiasing models, CRA-40-AD, are calculated by using CRA-40 as input data. To investigate the applicability of employing CRA-40 reanalysis to calculate atmospheric dealiasing model, the validation of resulted models was carried out from three aspects including spherical harmonic coefficients, KBRR residuals and geoid heights derived from time-variable gravity field models. Results: The results of the evaluations indicate that CRA40-AD exhibit a strong correlation with GFZ AOD1B RL06(RL06)in both spectral and time domains. The differences between CRA40-AD and RL06 in spectral domain are smaller than the GRACE simulation accuracy after 20 orders. The RMS differences of the KBRR residuals between CRA-40-AD and RL06 are below 20 nm/s, which conforms to the accuracy of GRACE K-band ranging system. The differences in geoid degree between CRA-40-AD and RL06 range from 0 to 0.6 mm, which satisfies the 1 mm geoid accuracy. Conclusions: Consequently, CRA-40 has been shown to have the potential to be used in atmospheric dealiasing models, making the fully localization of atmospheric dealiasing products promising to achieve.