Dynamic change of Ice Flow Velocity in Holmes Glacier Since the 1970s

Abstract. The Holmes Glacier is a major outlet glacier in Wilkes Land, East Antarctica, a region experiencing accelerated ice mass loss. To study the historical dynamic changes of the Holmes Glacier in East Antarctica, this study utilized Landsat MSS imagery to reconstruct a high-resolution velocity map of the glacier dating back to the 1970s. Our results reveals that the Holmes Glacier has experienced a long-term acceleration trend on its ice shelf since the 1970s, a trend that corresponds with observed ice shelf thinning and basal melting. Concurrently, there was no significant acceleration near the grounding line of Holmes West, whereas Holmes East showed marked acceleration, reflecting different conditions of modified Circumpolar Deep Water (mCDW) intrusion at the grounding lines of the two ice streams. A calving event was identified in March 2021, which occurred significantly earlier than previous events in its historically stable cycle, possibly indicating the reduced stability of the Holmes Ice Shelf. The high-resolution historical velocity data provided by this study reveal that the Holmes Glacier has shown an overall trend of destabilization and mass loss during the observation period. The study concludes that the observed acceleration is primarily driven by the basal melting of the ice shelf, which is caused by the intrusion of warm ocean water and the subsequent thinning of the ice shelf, provide a new historical perspective on the dynamics of Holmes glacier.