Updates to the global sea level budget: assessing trends and biases in ocean mass

Since 2002, the GRACE mission provides measurements of the time-variable ocean mass. The long-term upward trend in ocean mass can be attributed to glacier and ice sheet melting, while land water storage mainly causes inter annual to decadal variations related to ENSO and PDO large- scale climate variability. Due to GRACE's measurement system, estimating ocean mass requires a careful evaluation of averaging kernels and land-to-ocean leakage. Here, we provide an updated estimate of the global ocean mass changes with a particular focus on quantifying leakage errors and biases through 2016, using conventional spherical harmonic as well as newer mascon gravity solutions from GRACE. We evaluate our new ocean mass time series against the total sea level changes from altimetry and assess the role of upper and deep ocean steric changes from 2002 through 2016.