ICE SHEET MASS BALANCE INTERCOMPARISON EXERCISE PHASE III (IMBIE-3)

IMBIE has led to improved confidence in the measurement of ice sheet mass balance and the associated global sea-level contribution. The improvements were achieved through combination of ice sheet imbalance estimates developed from the independent satellite techniques of altimetry, gravimetry and the input-output method. Going forwards, IMBIE provides a framework for assessing ice sheet mass balance, and has an explicit aim to widen participation to enable the entire scientific community to become involved. The previous two phases led to a reduction in ice sheet mass balance uncertainties and showed a 6-fold increase in the rate of mass loss during the satellite era. In addition to continuing this exercise, the new phase of IMBIE includes new objectives designed to provide more robust and regular estimates of ice sheet mass balance and their contribution to global mean sea level rise. These new objectives are to: