The joint ESA/NASA Mass-change And Geosciences International Constellation (MAGIC) mission has the objective to extend time series from previous gravity missions, including an improvement of accuracy and spatio-temporal resolution. The long-term monitoring of Earth's gravity field carries information on mass-change induced by water cycle, climate change, and mass transport processes between atmosphere, cryosphere, oceans and solid Earth. The MAGIC mission will be composed of two satellite pairs flying in different orbit planes. The NASA/DLR--led first pair (P1) is expected to be in a near-polar orbit around 500 km of altitude; while the second ESA--led pair (P2) is expected to be in an inclined orbit of 65--70 degrees at approximately 400 km altitude. The ESA--led pair P2 Next Generation Gravity Mission (NGGM) shall be launched after P1 in a staggered manner to form the MAGIC constellation. The addition of an inclined pair shall lead to reduction of temporal aliasing effects and consequently of reliance on de-aliasing models and post-processing. The main novelty of the MAGIC constellation is the delivery of mass-change products at higher spatial resolution, temporal (i.e. sub--weekly) resolution, shorter latency, and higher accuracy than GRACE and GRACE-FO. This will pave the way to new science applications and operational services. The performances of different MAGIC mission scenarios for different application areas in the field of geosciences were analysed in the frame of the initial ESA Science Support activities for MAGIC. The data sets provided here are the Level-2a simulated gravity field solutions of MAGIC scenarios and the related reference signal that were used for these analyses.
The .gfc files in the folders monthly (31-day solutions) and weekly (7-day solutions) contain the estimated (HIS) coefficients (Cnm, Snm) as well as the formal errors (SigCnm, SigSnm) of the different MAGIC scenarios. In order to compute the coefficient errors, the reference/true HIS coefficients contained in the folder HIS_reference_fields need to be subtracted from the estimated HIS coefficients.
The data sets provided here comprise the Level-2a simulated gravity field solutions of MAGIC scenarios and the related reference signal (based on Dobslaw et al. 2014; 2015) that were used for the above analyses.
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.