Fram Strait sea ice export variability and September Arctic sea ice extent over the last 80 years

Abstract

Abstract.A new long-term data record of Fram Strait sea ice area export from 1935 to 2014 is developed using a combination of satellite radar images and station observations of surface pressure across Fram Strait. This data record shows that the long-term annual mean export is about 880 000 km 2 , representing 10 % of the sea-ice-covered area inside the basin. The time series has large interannual and multi-decadal variability but no long-term trend. However, during the last decades, the amount of ice exported has increased, with several years having annual ice exports that exceeded 1 million km 2 . This increase is a result of faster southward ice drift speeds due to stronger southward geostrophic winds, largely explained by increasing surface pressure over Greenland. Evaluating the trend onwards from 1979 reveals an increase in annual ice export of about +6 % per decade, with spring and summer showing larger changes in ice export (+11 % per decade) compared to autumn and winter (+2.6 % per decade). Increased ice export during winter will generally result in new ice growth and contributes to thinning inside the Arctic Basin. Increased ice export during summer or spring will, in contrast, contribute directly to open water further north and a reduced summer sea ice extent through the ice-albedo feedback. Relatively low spring and summer export from 1950 to 1970 is thus consistent with a higher mid-September sea ice extent for these years. Our results are not sensitive to long-term change in Fram Strait sea ice concentration. We find a general moderate influence between export anomalies and the following September sea ice extent, explaining 18 % of the variance between 1935 and 2014, but with higher values since 2004.

Satellite-derived sea-ice export and its impact on Arctic ice mass balance

“…The time series of winter ice volume export through the Fram Strait reveals a significant decrease of 500 km (Smedsrud et al, 2017) and thus, we also find a drop in ice thickness at the Fram Strait for 2012/2013, which is accompanied by a lower mean drift (Figure 4). In contrast, in winter season 2013/2014, which followed a cold Arctic summer with low melt rates (Tilling et al, 2015), ice thickness at the gate is increasing, accompanied by a higher mean drift (Figure 4).…”

“…A major difference 15 in the method is the choice of the position of the gate. Smedsrud et al (2017) placed the gate at 79…”

A 4.5 km resolution Arctic Ocean simulation with the global multi-resolution model FESOM 1.4

“…The two simulations produced very similar solid FW transports through the Fram Strait, well representing the observed value (Table 1). Although the sea ice area export through the Fram Strait has been increasing in recent decades due to increasing sea ice drift (e.g., Smedsrud et al, 2017), sea ice volume and thus solid FW export have been decreasing due to the thinning of Arctic sea ice. Compared to the estimate of the 1980-2000 period, the solid FW export flux decreased by 400 km 3 yr −1 in the 2000s (Haine et al, 2015).…”

Grand Challenges in Cryospheric Sciences: Toward Better Predictability of Glaciers, Snow and Sea Ice

“…There has been over 50% loss of sea-ice volume from the Arctic since 1979 (Schweiger et al, 2011;updated to 2015), which is primarily manifested as a loss of perennial ice area (Maslanik et al, 2011) through enhanced transpolar ice drift events (Nghiem et al, 2007), export to the Greenland-IcelandNorwegian Sea (Smedsrud et al, 2017), and increased melting within the Arctic (Kwok and Cunningham, 2010). The Antarctic has experienced a slight increase in sea-ice extent, but with large zonal variability, with increasing ice extent in the Ross Sea and decreasing extent in the Amundsen-Bellinghausen Sea (Turner et al, 2015).…”