The IMBIE project began in 2011, and produced its first estimate of ice sheet mass balance in 2012 as a direct contribution to the fifth assessment report of the Intergovernmental Panel on Climate Change (Shepherd et al., 2012). IMBIE 2012 included an international team of 47 scientists based in 26 separate institutions, and was co-led by Andrew Shepherd and Erik Ivins. The team had expertise in the techniques of satellite altimetry, gravimetry, and the input-output method, glacial isostatic adjustment, surface mass balance modelling, glaciology, and ice sheet modelling. The IMBIE project completed a series of inter-comparison experiments both within and between the different geodetic techniques, using standard time periods, geographical regions, ancillary datasets, and geophysical corrections. Reconciled estimates of ice sheet mass balance were calculated as the linear average of the individual estimates, and these data were integrated to form a time series of cumulative mass change within each of the four ice sheet regions of Greenland, East Antarctica, West Antarctic and the Antarctic Peninsula. Over the course of the 19-year IMBIE survey (1992 – 2011), the average rates of mass balance of the Antarctic and Greenland Ice Sheets were estimated to be -71 ± 53 and -152 ± 49 Gt yr-1, respectively.
The geographical distribution and contacts of the IMBIE 2012 participants.
The methodological approach taken by IMBIE 2012.
The key findings of IMBIE 2012.