Geodetic residual OAM are derived by calculating the geodetically observed angular momentum from the deconvolution of IERS 20C04 EOPs into the geodetic angular momentum (GAM) and subtracting the model-based contributions of atmosphere (AAM), terrestrial hydrology (HAM), and accounting for the global mass balance with the apropriate combination-dependent barystatic sea level contribution (SLAM). 

All available geodetic residuals GAHS can be downloaded here.

*SLE: Sea level equation representing the barystatic response of the global ocean required to conserve the total mass of the related surface fluid systems atmosphere (AAM) and terrestrial hydrology (HAM), see

Dobslaw et al. (2010), Seasonal polar motion excitation from numerical models of atmosphere, ocean, and continental
hydrosphere. Journal of Geophysical Research: Solid Earth, 115:10406.

Dill and Dobslaw (2019), Seasonal variations in global mean sea level and consequences on the excitation of length-of-day changes. Geophysical Journal
International, 218:801–816.

*OBP-barslv: Pressure variations due to mass inflow from the continents and deformations of the equipotential surface coincident with mean sea-level due to gravitational attraction of masses at the continents, see GravIS OBP technical note.