Recent Changes of the Earth’s land ice from GRACE: methods, signals and errors (Invited)

Recent changes in the cryosphere highlight the importance of methods for directly observing the complex spatial and temporal variation of the ice sheets and glacier systems. The NASA/DLR Gravity Recovery and Climate Experiment (GRACE) mission has been acquiring ultra-precise inter-satellite K-band range and range-rate (KBRR) measurements providing new observations of the complex evolution of the Earth’s land ice. The fidelity of the ice mass flux solutions depends on many factors including solution method, parameterization and processing of the GRACE level 1B data including forward modeling of various non-ice mass signals (e.g. hydrology, oceans, atmosphere). In this talk we present the latest GRACE derived ice mass solutions for the Gulf of Alaska glaciers, Greenland and Antarctica. We compare solutions derived from various techniques including those that estimate the mass flux directly from the GRACE observations (regional high-resolution mascon and global mascon solutions), as well as regional averaging kernel techniques applied to spherical harmonic solutions estimated from the GRACE data. We also explore the impact of forward modeling and parameterization on the final solutions. Solution results as well as errors and limitations will be discussed.