A Method to Calculate Elevation-Change Rate of Jakobshavn Isbrae Using Operation IceBridge Airborne Topographic Mapper Data

To bridge the data gap between Ice, Cloud, and land Elevation Satellite (ICESat) and the delayed forthcoming ICESat-2, the National Aeronautics and Space Administration has launched the Operation IceBridge (OI) campaign in 2009, which has provided variable data set to reveal snow and ice changes in the Arctic and Antarctic. In this letter, we employ the Airborne Topographic Mapper (ATM) data from OI to detect a five-year (between 2010 and 2015) elevation-change rate of Jakobshavn Isbrae (JI), the largest and fastest flowing outlet glacier in Greenland. Grid elevation of OI ATM is calculated and a method to calculate elevation-change rate using these grid data is implemented. The comparison of repeat grid elevation indicates that our method can generate unbiased elevation data. The uncertainty of grid elevation data using our method is approximately 1.0 m (standard deviation). The five-year average elevation rate of JI over regions with ice velocity ≥300 m/a between 2010 and 2015 was about -5.0 m/a (root mean square uncertainty: 0.7 m/a), with a maximum thinning rate of -18.2 m/a near the terminus of the main trunk. Compared with the previously reported elevation-change rates from earlier periods, JI has now reached a new high thinning record.