Sea ice thickness is an important variable for sea ice monitoring and climate projections. Although observations of ice extent and concentration have been available since late 1978, the same is not true for ice thickness. Because of the high interannual variability of the ice pack, climate trends in thickness and volume can only be observed over long time series. The earliest measurements of sea ice thickness (as multi-year averages for ERS-1 and ERS-2) were published...