Modeling the spreading of glacial meltwater from the Amundsen and Bellingshausen Seas

Abstract

It has been suggested that an increased melting of continental ice in the Amundsen Sea (AS) and Bellingshausen Sea (BS) is a likely source of the observed freshening of Ross Sea (RS) water. To test this hypothesis, we simulate the spreading of glacial meltwater using the Finite Element Sea Ice/Ice Shelf/Ocean Model. Based on the spatial distribution of simulated passive tracers, most of the basal meltwater from AS ice shelves flows toward the RS with more than half of the melt originating from the Getz Ice Shelf. Further, the model results show that a slight increase of the basal mass loss can substantially intensify the transport of meltwater into the RS due to a strengthening of the melt‐driven shelf circulation and the westward flowing coastal current. This supports the idea that the basal melting of AS and BS ice shelves is one of the main sources for the RS freshening.

Glacier change along West Antarctica's Marie Byrd Land Sector and links to inter-decadal atmosphere–ocean variability

“…This implies that the high volumes of meltwater originating from Getz Ice Shelf in recent years , even during steady-state conditions, may be sufficient to result in the enhanced modification of on-shelf CDW across this region of the MBLS. Hypothesized to become exacerbated by future increases in dynamic basal melting of Amundsen Sea ice shelves (Nakayama et al, 2014), this process may continue to limit CDW access to the sub-shelf cavity in the coming decades, and partly explain our observations of nearnegligible GL retreat and thinning rates between 2003 and 2015.…”

“…Finally, we acknowledge that the large meltwater fluxes originating from the Amundsen Sea Sector Rignot et al, 2013;Depoorter et al, 2013) may also play an important role in moderating ice-ocean interactions west of 135 • W. A recent modelling study suggests that up to one third of the total meltwater derived from the Amundsen Sea Sector is transported towards the Ross Sea (Nakayama et al, 2014). Within this trend, up to 50 % of the total meltwater content delivered to the Ross Sea originates from Getz Ice Shelf via a pronounced easterly coastal current, and Ross-Sea-bound meltwater-transportation pathways flood the entire width of the continental shelf west of 135 • W (Nakayama et al, 2014;their Figs.…”

“…Relative to panel (a), the strong easterly coastal current, comprising fresh Antarctic surface water (including Ross Sea-bound melt waters from Getz Ice Shelf and the wider Amundsen Sea Sector), acts to freshen the continental shelf water column (cf. Nakayama et al, 2014), resulting in buffered modified CDW access to the subice shelf cavity. G and I b refer to the true grounding line and the ice-sheet-shelf margin inflexion point, respectively.…”

“…Within this trend, up to 50 % of the total meltwater content delivered to the Ross Sea originates from Getz Ice Shelf via a pronounced easterly coastal current, and Ross-Sea-bound meltwater-transportation pathways flood the entire width of the continental shelf west of 135 • W (Nakayama et al, 2014;their Figs. 2b and 3c).…”

Meteorology and oceanography of the Atlantic sector of the Southern Ocean—a review of German achievements from the last decade

“…Part of the meltwater injected into Amundsen Sea is advected northward and into the ACC (Kusahara and Hasumi 2014) while the other part is transported with the coastal current into the Ross Sea. Here, according to a numerical study (Nakayama et al 2014), the meltwater is likely to be responsible for the observed longterm decrease of shelf water salinity (Jacobs et al 2002). The freshening in the Ross Sea, in turn, is suggested to have caused the decline in the salinity of the AABW in the Australian Antarctic Basin (Rintoul 2007).…”