Abstract:

The relatively warm Circumpolar Deep Water (CDW) has been intruding on the Amundsen Sea continental shelf in recent decades and melting the ice shelves from below, resulting in a continuous ice mass loss in the Amundsen Sea sector of the West Antarctic Ice Shelf. Analysis of the pathways and variations of the CDW intrusion onto the shelf is of great importance to understanding the phenomena of rapid ice shelf thinning and grounding line retreat in this sector. Based on GLORYS12V1 [Global Ocean (1/12)° Physical Reanalysis] data, we calculated the volume and heat transport in the western, central, and eastern channels. We analyzed the relationship between the variations in temperature and salinity of the CDW on the shelf and its flow field. Results showed that the CDW invaded the Dotson–Getz Trough from the western channel, while it invaded the Pine Island Trough from the central and eastern channels. The volume and heat transport of the CDW intruding on the shelf through the western channel showed a weak upward trend over time. The volume and heat transport of the CDW to the Pine Island Trough through the central channel was about twice as much as that through the eastern channel. The temperature of the CDW intrusion into these troughs was controlled by the temperature of the CDW, when it invaded the shelf, and by subsequent processes on the continental shelf.

Key words: Circumpolar Deep Water, Amundsen Sea shelf, flow field structure, volume transport, heat transport