Regionalnaya model’ dinamiki l’da. Chast’ 1. Opisaniye modeli, postanovka chislennogo eksperimentov i sovremennaya dinamika potoka v oksrestnostiakh stantsii Konen (in Russian; Regional ice-dynamic model. Part 1. Model description, performance of numerical experiments, and present-day ice-flow dynamics around Kohnen station)

Considered in this study are methodological issues of a detailed reconstruction of the time-dependent ice flow in a limited area in Dronning Maud Land, Antarctica. The nested domain of 600×400 km is located around Kohnen Station, where the deep drilling has been completed. The key point of our approach to regional modeling consists in separation of the model macro- and regional scale ice dynamics. We couple a time-dependent 3-D comprehensive model of the whole Antarctic ice sheet employing Shallow Ice Approximation dynamics (Big Model, or BM) with a steady3state model of the incomplete second-order approximation (Small Model, or SM). All prognostic calculations take place within BM, which simulates evolution of the Antarctic ice sheet through eight glacial cycles. SM receives boundary conditions from BM at lateral boundaries through a transition zone to eliminate the effects of different spatial resolution (20 km in BM and 2.5 in SM), but there is no feedback between SM and BM. SM assimilates the up-to-date observational data on accumulation rate and bedrock topography. In the numerical experiments we reconstruct history of variations of the surface and bed topography, accumulation rate and 3-D velocity field in the nested domain. Model estimate of the surface velocity at Kohnen is close to the observational one.