Restratification Structure and Processes in the Irminger Sea

Abstract

In the Atlantic upper ocean, warm and saline waters are transported northward in the AMOC's upper limb from the equator to high latitudes, where they are transformed into colder and denser waters. These dense waters can spread to the AMOC's lower limb in the deep ocean, where they remain isolated from the atmosphere for hundreds of years (England, 1995). Thus the AMOC has an important effect on the ocean's uptake and storage of heat and anthropogenic CO 2 from the atmosphere (Brown et al., 2021;Fröb et al., 2016). One of the processes that adds to the water mass transformation at high latitudes is deep convection. Deep convection can theoretically be described as a three-phase process (de

Delayed Recovery of the Irminger Interior From Cooling in 2015 Due To Widespread Buoyancy Loss and Suppressed Restratification

“…The restratification of the subsurface water column is shown to be due to eddy‐shedding from the IC along the Reykjanes Ridge, primarily as a result of baroclinic instabilities. This result is consistent with findings in the Labrador Sea (de Jong et al., 2016; Spall, 2004; Straneo, 2006a) and speculations about the Irminger Sea (Fan et al., 2013; Sterl & de Jong, 2022). The delayed recovery of the interior is a direct outcome of the changing horizontal density gradient that drives growth of baroclinic instabilities.…”

“…As such, it is expected that exchange with the eastern boundary dominates the convergence of buoyant water on the interior. This is consistent with idealized and observational studies in both the Labrador and Irminger Seas (Spall, 2004; Sterl & de Jong, 2022; Straneo, 2006b; Våge et al., 2011); with Fan et al. (2013) showing that the most buoyant eddies found in the Irminger interior are from the eastern boundary.…”

Cross‐Shelf Exchanges Between the East Greenland Shelf and Interior Seas

“…While recent observations suggested that overturning east of Greenland dominates the total overturning in the SPNA (Li et al., 2021; Lozier et al., 2019; Petit et al., 2020), studies of the impact of additional freshwater input on deep convection and deep water formation mostly focused on the Labrador sea so far (e.g., Pennelly et al., 2019; Yang et al., 2016). In summer, shallow freshwater layers are seen over the deep convection region in the Irminger Sea (Sterl & de Jong, 2022). In winter, this layer is mixed down the water column by convective mixing, which reaches down to 400 m even in weak winters (M. F. de Jong et al., 2012).…”

“…In winter, this layer is mixed down the water column by convective mixing, which reaches down to 400 m even in weak winters (M. F. de Jong et al., 2012). The re‐formation of a new freshwater layer over a few months in spring (Sterl & de Jong, 2022) suggests that it is fed by local sources. This restratification process in the Irminger Sea and the possibility of additional freshwater inhibiting convection in the Irminger and Nordic Seas, underline the need for a better understanding of freshwater pathways east of Greenland.…”

“…and deep water formation mostly focused on the Labrador sea so far (e.g., Pennelly et al, 2019;Yang et al, 2016). In summer, shallow freshwater layers are seen over the deep convection region in the Irminger Sea (Sterl & de Jong, 2022). In winter, this layer is mixed down the water column by convective mixing, which reaches down to 400 m even in weak winters (M. F. de Jong et al, 2012).…”