Towards a new ITSG-Grace release: updated data products and improvements within the processing chain

The Institute of Geodesy of the Graz University of Technology has a successful record in producing GRACE/GRACE-FO gravity fields using an in-house developed software, the Gravity Recovery Object Oriented Programming System (GROOPS). The ITSG-Grace2018 gravity field model is the latest release of the ITSG sequence covering the complete GRACE/GRACE-FO time-span. The new release will be based on planned Level-1B Release 05 data and the AOD1B Release 07 dealiasing product. It will include a static field, unconstrained monthly, as well as Kalman smoothed daily solutions.

Updates and improvements over the previous release are summerized as follows: (a) We revisit the Level-1A processing of transplant accelerometer data and co-estimate their unmodeled linear accelerations due to thruster activities; (b) We improve the estimation of subdaily high-frequency mass variations by increasing both temporal and spatial resolutions; (c) Taking advantage of the available GRACE-FO LRI measurements, we introduce combined KBR and LRI gravity field solutions based on a stochastic modeling that determines proper weighting between KBR and LRI observations.

This contribution will highlight the selected parts of the processing chain and their effect on the estimated gravity field solutions.