ITSG-Grace2018 - Monthly, Daily and Static Gravity Field Solutions from GRACE

The ITSG-Grace2018 gravity field model is the latest GRACE-only gravity field model computed at Graz University of Technology, providing unconstrained monthly and regularized daily solutions as well as a long-term static field. For each month of the observation period, sets of spherical harmonic coefficients for different maximum degrees (60, 96, 120) were estimated without applying any regularization. In order to resolve high-frequency gravity field variations as detailed as possible, a set of spherical harmonic coefficients up to degree and order 40 was co-estimated. K-band range rates with a sampling of 5 seconds and kinematic orbits with a sampling of 5 minutes were used as observations. The kinematic orbits of the GRACE satellites (Zehentner and Mayer-Gürr 2013, 2014) were processed using the GPS orbits and clock solutions provided by CODE. Additionally, a full accelerometer scale factor matrix was estimated per day (Klinger and Mayer-Gürr, 2016). The accelerometer bias was modelled through cubic splines with a node interval of six hours and estimated for each axis and day. Detailed information about ITSG-Grace2018 is available at http://ifg.tugraz.at/ITSG-Grace2018. The monthly and daily data covers the period between April 2002 and August 2016.