Computation and Mass 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 The 40 year global reanalysis dataset released by China Meteorological Administration(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 make. A set of AD (atmospheric dealiasing) models, CRA-40-AD, is calculated by using CRA-40 as input data. To investigate the applicability of employing CRA-40 to calculate AD model, the validation of resulted models is carried out from three aspects including spherical harmonic coefficients, K-band range rate (KBRR) residuals and geoid heights derived from time-variable gravity field models.

Results The results of the evaluations indicate that CRA‑40-AD exhibit a strong correlation with GFZ AOD1B RL06（RL06） in both spectral and time domains. The differences between CRA‑40-AD and RL06 in spectral domain are smaller than the GRACE simulation accuracy after 20 orders. The root mean square differences of KBRR residuals between CRA-40-AD and RL06 are below 20 nm/s, which conforms to the accuracy of gravity recovery and climate experiment (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 AD models, making the fully localization of AD products promising to achieve.