LDCmgm90 monthly geopotential model set with separate GIA model

This is an updated version of LDCmgm90, which has assimilated CSR RL06 mascon and GSFC SLR degree-2 Stokes coefficients besides all the data sets used in the previous version (see https://www.nature.com/articles/s41597-019-0239-7 for more details).
In addition, The ICE-6G_C used for RL05 mascons, and ICE-6G_D used for RL06 mascons are added back because there are still somewhat large uncertainties in GIA modeling. Instead, we provide a corrected GIA model ICE6Gavg(GPS) as a separate data set (see the attached pdf for more details about this GIA model).While the GRACE
(Gravity Recovery and Climate Experiment) satellite mission is of great
significance in understanding various branches of Earth sciences, the quality
of GRACE monthly products can be unsatisfactory due to strong longitudinal stripe-pattern
errors and other flaws. Based on corrected GRACE Mascon (mass concentration) gridded
mass transport time series and updated LDCgam (Least Differential Combination global
angular momenta) data, we present a new set of monthly gravity models called
LDCmgm90, in the form of Stokes coefficients with order and degree both up to
90. The LDCgam inputs are developed by assimilating degree-2 Stokes
coefficients from various versions of GRACE (including Mascon products) and SLR
(Satellite Laser Ranging) monthly gravity data into combinations of outputs
from various global atmospheric, oceanic, and hydrological circulation models,
under the constraints of accurately measured Earth orientation parameters in
the Least Differential Combination (LDC) scheme. Taking advantages of the relative
strengths of the various input solutions, the LDCmgm90 is free of stripes and
some other flaws of classical GRACE products.