Article

Arctic Sea Ice Retreat in 2007 Follows Thinning Trend

Journal of Climate (Impact Factor: 4.44). 01/2009; 22(1). DOI: 10.1175/2008JCLI2521.1

ABSTRACT

The minimum of Arctic sea ice extent in the summer of 2007 was unprecedented in the historical record. A coupled ice–ocean model is used to determine the state of the ice and ocean over the past 29 yr to investigate the causes of this ice extent minimum within a historical perspective. It is found that even though the 2007 ice extent was strongly anomalous, the loss in total ice mass was not. Rather, the 2007 ice mass loss is largely consistent with a steady decrease in ice thickness that began in 1987. Since then, the simulated mean September ice thickness within the Arctic Ocean has declined from 3.7 to 2.6 m at a rate of 0.57 m decade 1 . Both the area coverage of thin ice at the beginning of the melt season and the total volume of ice lost in the summer have been steadily increasing. The combined impact of these two trends caused a large reduction in the September mean ice concentration in the Arctic Ocean. This created conditions during the summer of 2007 that allowed persistent winds to push the remaining ice from the Pacific side to the Atlantic side of the basin and more than usual into the Greenland Sea. This exposed large areas of open water, resulting in the record ice extent anomaly.

Download full-text

Full-text

Available from: Axel Schweiger, Jul 10, 2014
  • Source
    • "The factors influencing storage and release relate to the wind stress curl over the central Arctic (Proshutinsky et al. 2009) that in ice-covered seas is modified by sea ice. Changes in the spatial distribution of sea ice and wind stress curl contribute to a myriad of observed Arctic changes such as the shift in the boundary between Atlantic-and Pacific-derived waters (Morison et al. 1998); a shift in the position of the transpolar drift (Rigor et al. 2002); retreat and return of the cold halocline in the Eurasian basin (Alkire et al. 2007); reduced pack ice (Lindsay et al. 2009); changes in freshwater content (Polyakov et al. 2008; Rabe et al. 2014); increased runoff into the Eurasian sector (Peterson et al. 2002); and many more (White et al. 2007). Meanwhile, Arctic freshwater export impacts downstream deep-water formation zones in the Greenland and Labrador Seas. "

    Full-text · Dataset · Dec 2015
  • Source
    • "The factors influencing storage and release relate to the wind stress curl over the central Arctic (Proshutinsky et al. 2009) that in ice-covered seas is modified by sea ice. Changes in the spatial distribution of sea ice and wind-stress curl contribute to a myriad of observed Arctic changes such as the shift in the boundary between Atlantic-and Pacific-derived waters (Morison et al. 1998); a shift in the position of the trans-polar drift (Rigor et al. 2002); retreat and return of the cold halocline in the Eurasian Basin (Alkire et al. 2007); reduced pack ice (Lindsay et al. 2009); changes in freshwater content (Polyakov et al. 2008; Rabe et al. 2014); increased run-off into the Eurasian sector (Peterson et al. 2002); and many more (White et al. 2007). Meanwhile, Arctic freshwater export impacts downstream deep water formation zones in the Greenland and Labrador Seas. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Time series observations of velocity, salinity, pressure, and ice draft provide estimates of advective fluxes in Nares Strait from 2003 to 2009 at daily to interannual time scales. Velocity and salinity are integrated across the 36 km wide and 350 m deep channel for two distinct multi-year periods of sea ice cover. These observations indicate multi-year mean fluxes that range from 0.71±0.09 to 1.03±0.11 Sv (Sv=10 −6 m 3 s −1 =31,536 km 3 yr −1) for volume and from 32±5.7 to 54±9.3 mSv for oceanic freshwater relative to a salinity of 34.8 for the first 2003-06 and second 2007-09 periods, respectively. Advection of ice adds another 8±2 mSv or 260±70 km 3 per year to the freshwater export. Flux values are larger when the sea ice is mobile all year. About 75% of the oceanic volume and freshwater flux variability is correlated at daily to interannual time scales. Flux variability peaks at a 20-day time scale and correlates strongly with along-channel pressure gradients (r 2 = 0.68). The along-channel pressure gradient peaks in early spring when the sea ice is often motionless with higher sea level in the Arctic that drives the generally southward ocean circulation. Local winds contribute only when the sea ice is mobile when they explain 60% its variance (r 2 = 0.60). Observed annual to interannual change in the duration of motionless sea ice conditions impacts ocean stratification and freshwater flux while seasonal variations are small. [Accepted for publication, J.
    Full-text · Article · Aug 2015 · Journal of Physical Oceanography
  • Source
    • "The mean sea ice thickness of the Arctic has been decreasing since the 1980s (Lindsay and Zhang, 2005; Rigor et al., 2004), and the sea ice extent reached minimum values in 2007 and 2008 (Lindsay et al., 2009). "

    Full-text · Dataset · May 2014
Show more