Research ArticleOCEANOGRAPHY

Warming of the interior Arctic Ocean linked to sea ice losses at the basin margins

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Science Advances  29 Aug 2018:
Vol. 4, no. 8, eaat6773
DOI: 10.1126/sciadv.aat6773

Figures

  • Fig. 1 Temperature and salinity in the BG.

    (A) Temperature and depth profiles in March 1992, 2008, and 2015 and (B) the same profiles on the temperature-salinity plane. The dashed-dotted black line indicates the freezing temperature at zero pressure, and the vertical dashed lines mark S = 31 and S = 33. (C) and (D) are the same, with the profiles being from September 1992, 2008, and 2015. Heat content (Q, J m−2) relative to the freezing temperature integrated between the isohalines S = 31 and S = 33 is shown in (A) and (C) for the profiles plotted. All profiles are in the vicinity of the diamond shown in the regional map (E), which was free of sea ice in September 2008 and 2015, and ice covered for the other profiles (contours indicate the monthly sea ice edge; 15% concentration); the cyan boundary delineates the BG region.

  • Fig. 2 Maps of heat content in the BG warm halocline.

    (A to E) Heat content (J m−2) relative to the freezing temperature integrated between the isohalines S = 31 and S = 33 for all data (including all seasons) in the periods (A) 1987–2001, (B) 2002–2005, (C) 2006–2009, (D) 2010–2013, and (E) 2014–2017. The hatched region in (E) is the NCS region of strongest subduction (see text). The cyan boundary delineates the BG region considered in the time series calculations. The gray bathymetric contour marks the 100-m isobath, and black dots indicate temperature-salinity profile locations. Black contours on each panel indicate the monthly sea ice edge (15% concentration) for the month labeled.

  • Fig. 3 BG warm halocline time series.

    (A) Time series of total heat content (J) relative to the freezing temperature integrated between the isohalines S = 31 and S = 33 in the BG region delineated by the cyan line in Fig. 2. (B) Time series of average thickness (m) (left y axis) and layer-averaged temperature (°C) (right y axis) of the layer bounded by S = 31 and S = 33 over the BG region.

  • Fig. 4 Time series in the NCS.

    Time series of cumulative heat input (MJ m−2) for the months of July to September into the NCS (see Fig. 2E). Shading indicates 1 SD based on variance over the region. Fractional sea ice concentration (note inverted axis) and SST (°C) averaged over the same area for the same months are also shown.

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