This paper discusses strategies to improve the GRACE gravity field monthly solutions computed at the Astronomical Institute of the University of Bern. We updated the input observations and background models, as well as improving processing strategies in terms of instrument data screening and instrument parameterization.

Earth's gravity field provides invaluable insights into the state and changing nature of our planet. GOCO06s combines over 1 billion measurements from 19 satellites to produce a global gravity field model. The combination of different observation principles allows us to exploit the strengths of each satellite mission and provide a high-quality data set for Earth and climate sciences.

Correctly determining the orbit of Earth-orbiting satellites requires to account multiple background effects which appear in the system Earth. Usually, these effects are introduced by various complex force models, which are not always easy to handle. We publish and validate a data set of commonly used models to make it easier to track down potential issues when applying such background forces in orbit and gravity field determination.

We compute gravity field solutions from kinematic orbit positions of GRACE. These positions are derived from GPS based observations, and hence, they are contaminated by measurement noise. We present three methods of dealing with the noise in the data to obtain not only high-quality gravity field solutions but also an accurate quality information of the gravity fields.

Although not the primary mission of the Swarm three-satellite constellation, the sensors on these satellites are accurate enough to measure the melting and accumulation of Earth’s ice reservoirs, precipitation cycles, floods, and droughts, amongst others. Swarm sees these changes well compared to the dedicated GRACE satellites at spatial scales of roughly 1500 km. Swarm confirms most GRACE observations, such as the large ice melting in Greenland and the wet and dry seasons in the Amazon.