Articles | Volume 8, issue 2
Research article
20 Apr 2017
Research article |  | 20 Apr 2017

Two-dimensional prognostic experiments for fast-flowing ice streams from the Academy of Sciences Ice Cap

Yuri V. Konovalov and Oleg V. Nagornov

Abstract. Prognostic experiments for fast-flowing ice streams on the southern side of the Academy of Sciences Ice Cap on Komsomolets Island, Severnaya Zemlya archipelago, were undertaken in this study. The experiments were based on inversions of basal friction coefficients using a two-dimensional flow-line thermocoupled model and Tikhonov's regularization method. The modeled ice temperature distributions in the cross sections were obtained using ice surface temperature histories that were inverted previously from borehole temperature profiles derived at the summit of the Academy of Sciences Ice Cap and the elevational gradient of ice surface temperature changes (about 6.5 °C km−1). Input data included interferometric synthetic aperture radar (InSAR) ice surface velocities, ice surface elevations, and ice thicknesses obtained from airborne measurements, while the surface mass balance was adopted from previous investigations for the implementation of both the forward and inverse problems. The prognostic experiments revealed that both ice mass and ice stream extent declined for the reference time-independent surface mass balance. Specifically, the grounding line retreated: (a) along the B–B′ flow line from  ∼  40 to  ∼  30 km (the distance from the summit), (b) along the C–C′ flow line from  ∼  43 to  ∼  37 km, and (c) along the D–D′ flow line from  ∼  41 to  ∼  32 km, when considering a time period of 500 years and assuming a time-independent surface mass balance. Ice flow velocities in the ice streams decreased with time and this trend resulted in the overall decline of the outgoing ice flux. Generally, the modeled glacial evolution was in agreement with observations of deglaciation of the Severnaya Zemlya archipelago.

Short summary
The prognostic experiments conducted with the reference mass balance show that the grounding line would retreat by about 10 km in the three ice streams over a time period of 500 years. In the experiments, the ice flow velocities in the ice streams decreased with time. These trends in the ice flow velocities diminished the overall ice flux. The modeled evolution of the ice streams is in agreement with observations of ice mass loss in Severnaya Zemlya archipelago (Moholdt et al., 2012).
Final-revised paper