We focus on the Arctic Ocean between Svalbard and Franz Joseph Land in order to elucidate the possible role of Atlantic water (AW) inflow in shaping ice conditions. Ice conditions substantially affect the temperature regime of the Spitsbergen archipelago, particularly in winter. We test the hypothesis that intensive vertical mixing at the upper AW boundary releases substantial heat upwards that eventually reaches the under-ice water layer, thinning the ice cover. We examine spatial and temporal variation of ice concentration against time series of wind, air temperature, and AW temperature. Analysis of 1979–2011 ice properties revealed a general tendency of decreasing ice concentration that commenced after the mid-1990s. AW temperature time series in Fram Strait feature a monotonic increase after the mid-1990s, consistent with shrinking ice cover. Ice thins due to increased sensible heat flux from AW; ice erosion from below allows wind and local currents to more effectively break ice. The winter spatial pattern of sea ice concentration is collocated with patterns of surface heat flux anomalies. Winter minimum sea ice thickness occurs in the ice pack interior above the AW path, clearly indicating AW influence on ice thickness. Our study indicates that in the AW inflow region heat flux from the ocean reduces the ice thickness. 1. Introduction Steady reduction of the Arctic sea ice cover throughout 1990s has accelerated in the 2000s [1, 2]. As demonstrated in the recent studies, causative mechanisms for the extreme ice area/volume decay include an anomalous atmospheric circulation which forced ice out of the Canadian Basin towards Fram Strait [3, 4], the influence of warm inflow through Bering/Fram straits [5, 6], and the melting effect of warmed surface water [7]. However, long-term preconditioning occurred during three decades of steady ice thinning [8, 9]. This was largely a result of the fact that the Arctic has warmed up about twice as fast as lower latitudes due to the so-called polar amplification [10–12]. Years of reduced ice growth in winter and enhanced ice melt in summer led to the dominance of first-year ice over multiyear ice after 2004 [13]. Under conditions of enhanced seasonality, the influence of ocean heat on Arctic ice cover is expected to grow. The retreating summer ice edge increases the size of the marginal ice zones (MIZs)—the transient areas between open water and totally ice-covered ocean. For the Spitsbergen region, this process is particularly important due to the existence of an extended open water area (a quasi-steady-state
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