Fram Strait sea ice export affected by thinning: comparing high-resolution simulations and observations

Abstract

Variability and trends of Fram Strait sea ice area and volume exports are examined for the period of 1990-2010. Simulations from a high-resolution version of the MPIOM model (STORM project) reproduce area and volume export well when compared with NSIDC and ICESat satellite data and in-situ ice thickness observations. The fluxes derived from ice thickness and drift satellite products vary considerably, indicating a high uncertainty in these estimates which we mostly assign to the drift observations. The model captures the observed average seasonal cycles and interannual variability of ice export. The simulated mean annual sea ice area export is 860 × 10 3 km 2 a − 1 (1990-2010), and the correlation with the NSIDC-based area fluxes is r = 0.67. The simulated mean annual volume export is 3.3 × 10 3 km 3 a − 1 (1990-2010), close to the ICESat/ULS values, with a correlation of r = 0.58. The simulated monthly area export has a significant positive trend of + 10% per decade, explained by wind forcing. The major contribution to the robust trend in area export between June and September. Fram Strait ice volume export variability is mainly controlled by ice drift with a dominant role of the Transpolar Drift and, to a lesser extent thickness variability. The area export increase reflects increasing ice-drift speed, but is balanced with a reduced thickness over time when it comes to volume export, giving no significant trend in volume export. The spatial variability of ice drift indicates that the export influences a large area upstream in the Trans-Polar Drift stream, and that high volume export events lead to a thinner thickness there. The central Arctic is well connected drift-wise to the Fram Strait via the Transpolar Drift while for thickness, the region north of Greenland is dominated and controlled by the Fram Strait ice export.

Methane cycling within sea ice: results from drifting ice during late spring, north of Svalbard

“…The vertical distribution of impermeable and permeable layers during ongoing ice melt is associated with different methane pathways (Zhou et al, 2014). As the melting front advances vertically trough the ice, the brine networks within the sea ice expand, transporting the methane dissolved in the brine downwards.…”

“…Hence, in these shallow shelf seas, methane released from the sediment may be entrapped in sea ice during ice formation (Damm et al, 2015). Methane uptake in sea ice happens in different ways: as dissolved gas in the brine or as microbubbles directly in the ice matrix (Zhou et al, 2014). After its formation on the Siberian shelves, sea ice loaded with methane is transported by the wind away from the source area and towards Fram Strait by the Transpo-lar Drift (TPD; Damm et al, 2018;Krumpen et al, 2019).…”

Biomarker Distributions in (Sub)‐Arctic Surface Sediments and Their Potential for Sea Ice Reconstructions

“…The majority of Arctic sea ice export (860 × 10 3 km 2 /a; Zamani et al, 2019) occurs via western Fram Strait by the East Greenland Current (EGC), which flows south along the East Greenland coast and carries large amounts of Arctic water masses and sea ice into the North Atlantic (Figure 1; Aagaard & Coachman, 1968a, 1968b). Sea ice formation starts on the shallow shelves of the Arctic Ocean.…”

Arctic Sea Ice Decline Preconditions Events of Anomalously Low Sea Ice Volume Export Through Fram Strait in the Early 21st Century

“…Enhanced sea ice export through Fram Strait can facilitate the development of summer low sea ice extent in the Arctic (J. Wang et al., 2009; Williams et al., 2016) and reduce Arctic sea ice thickness, especially north of Greenland (Zamani et al., 2019). Furthermore, changes in Fram Strait sea ice volume export can influence the supply of ocean heat to the Arctic Atlantic Water layer by changing the ocean circulation in the Nordic Seas (Q. Wang et al., 2020).…”