Estimation of Sea Ice Production in the North Water Polynya Based on Ice Arch Duration in Winter During 2006–2019

Abstract

Polynyas are mesoscale oceanic phenomena observed in polar regions during the sea ice freezing season. A polynya is an area composed of open water and thin ice, even when air temperature is well below freezing (Morales Maqueda et al., 2004). Formation of polynyas is driven by one or both of the following two mechanisms. The first mechanism, which is called the latent heat mechanism, is wind-driven, triggered by persistent strong wind that removes the ice as soon as it forms, leaving the ocean surface exposed to the freezing temperature. This can be widely found in the Antarctic sea ice region. The second mechanism, which is called the sensible heat mechanism, is driven by the upwelling of warm water that accelerates the melting of the existing ice and delays the formation of new ice (Morales Maqueda et al., 2004). Polynyas affect the physical, biological, and chemical processes operating at the atmosphere-ocean interface at local and regional scales (

Evolving relationship of Nares Strait ice arches on sea ice along the Strait and the North Water, the Arctic’s most productive polynya

“…Over the NOW, the changes are more nuanced with reduced ice cover present for both categories but with ice concentrations in the no southern arch category higher by 10–20%. This suggests that contrary to previous work 14 – 17 , a southern arch is not necessary for the existence of the NOW. Given the observed reduction in the stability and duration of the Nares Strait ice arches 8 , 15 , 37 , the absence of a southern arch case may become the status quo moving forward.…”

“…The presence of either type of arch leads to a cessation of the export of Arctic sea ice down the Strait 8 , 13 . In addition, it has been argued that the presence of a southern arch, by restricting the southward movement of sea ice thereby allowing the northerly winds along the strait to sweep any remaining ice out of the region, is necessary for the existence of the NOW 14 – 17 . There is evidence that the stability of the arches is weakening 8 and there is concern that this may impact the existence of the NOW as a unique recurring polynya with its high level productivity, its complex ecosystem and its use as a traditional food source for nearby Inuit communities 1 , 14 .…”

“…1 ). It has been argued that the presence of a southern ice arch, by limiting the southward transport of sea ice, is required for the existence of the NOW 14 – 17 . High winds that arise due to flow distortion associated with the narrowness of Smith Sound also contribute to the presence of open water by sweeping any sea ice downstream 16 , 18 , 19 .…”

Marine diatoms record Late Holocene regime shifts in the Pikialasorsuaq ecosystem

“…However, it is worth noting that the water mass assembly and nutrient content entering Nares Strait from the Lincoln Sea vary under different atmospheric forcing patterns (i.e., Arctic Oscillation modes), with increased contribution of the fresher and nutrient‐depleted (nitrate concentrations below 1 μM during winter; Brown et al, 2020) surface waters of the Canada basin during positive phases of the Arctic Oscillation and increased contribution of the comparatively nutrient‐rich waters (nitrate concentrations up to 3.5 μmol kg −1 ) of the Siberian shelves during neutral/negative phases of the Arctic Oscillation (Burgers et al, 2023). Pacific‐derived Arctic waters that are modified by meltwater input during their transit through the Canadian Arctic Archipelago also enter the NOW from the west through the shallower Lancaster (sill depth 125 m) and Jones (sill depth 190 m) sounds (Lehmann et al, 2022; Ren et al, 2022).…”

“…By contrast, when the ice arch does not form, such as during the 2006/2007 winter, ice is advected year‐round through Nares Strait from north to south (Münchow et al, 2007) and the polynya fails to form until late May. The NOW is thus tightly influenced by changes in atmospheric temperature and circulation, which impact sea‐ice dynamics and ocean circulation (e.g., Ren et al, 2022) and can push the ecosystem into different functioning modes. Understanding the evolution of the NOW through the Late Holocene can thus provide context to assess the future trajectory of this ecosystem.…”