Variable Basal Melt Rates of Antarctic Peninsula Ice Shelves, 1994–2016

We have constructed 23-year (1994–2016) time series of Antarctic Peninsula (AP) ice-shelf height change using data from four satellite radar altimeters (ERS-1, ERS-2, Envisat, and CryoSat-2). Combining these time series with output from atmospheric and firn models, we partitioned the total height-change signal into contributions from varying surface mass balance, firn state, ice dynamics, and basal mass balance. On the Bellingshausen coast of the AP, ice shelves lost 84 ± 34 Gt a−1 to basal melting, compared to contributions of 50 ± 7 Gt a−1 from surface mass balance and ice dynamics. Net basal melting on the Weddell coast was 51 ± 71 Gt a−1. Recent changes in ice-shelf height include increases over major AP ice shelves driven by changes in firn state. Basal melt rates near Bawden Ice Rise, a major pinning point of Larsen C Ice Shelf, showed large increases, potentially leading to substantial loss of buttressing if sustained.