The effect of ocean heat flux on seasonal ice growth in Young Sound (Northeast Greenland)

Abstract

The seasonal ice cover plays an important role in the climate system limiting the exchange of heat and momentum across the air‐water interface. Among other factors, sea ice is sensitive to the ocean heat flux. In this study, we use in situ oceanographic, sea ice, and meteorological data collected during winter 2013/2014 in Young Sound (YS) fjord in Northeast Greenland to estimate the ocean heat flux to the landfast ice cover. During the preceding ice‐free summer, incident solar radiation caused sea surface temperatures of up to 5–6°C. Subsequently, this heat was transferred down to the intermediate depths, but returned to the surface and retarded ice growth throughout winter. Two different approaches were used to estimate the ocean heat fluxes; (i) a residual method based on a 1‐D thermodynamic ice growth model and (ii) a bulk parameterization using friction velocities and available heat content of water beneath the ice. The average heat flux in the inner YS varied from 13 W m−2 in October–December to less than 2 W m−2 in January–May. An average heat flux of 9 W m−2 was calculated for the outer YS. Moreover, we show that the upward heat flux in the outer fjord is strongly modulated by surface outflow, which produced two maxima in heat flux (up to 18–24 W m−2) during 26 December to 27 January and from 11 February to 14 March. By May 2014, the upward ocean heat flux reduced the landfast ice thickness by 18% and 24% in the inner and outer YS, respectively.

The Inferred Formation of a Subice Platelet Layer Below the Multiyear Landfast Sea Ice in the Wandel Sea (NE Greenland) Induced by Meltwater Drainage

“…Despite the large number of these artificial returns, some consistent returns between 2.5 and 3.3 m were recorded between late June and mid-July, which correspond with our inferred depths of the platelet layer. Earlier studies using the same model of IMB and underwater sonar demonstrated good agreement between the sounder derived ice thickness and the ice thickness inferred from the temperature string (Kirillov et al, 2015). Therefore, we are confident in the returns other than the artificial returns at 3.8 m depth.…”

Wintertime water dynamics and moonlight disruption of the acoustic backscatter diurnal signal in an ice‐covered Northeast Greenland fjord

“…[], Basedow et al . [], and Marcus and Scheef []. The polynya‐enhanced cell circulation was accompanied by a relative increase in temperature of the subsurface layer (from an average of −1.76°C up to −1.70 f°C) that resulted in the upward heat flux to the ice‐water interface by up to 22–24 W/m 2 at the outer fjord (moorings m02 and m03 ) and up to 14.5 W/m 2 in the inner fjord (mooring m04 ) [ Kirillov et al ., ]. The relatively strong thermal gradient, observed by Dmitrenko et al .…”

“…In addition, an ice‐mass balance buoy (IMB) [ Babb et al ., ; Kirillov et al ., ] deployed at the m04 position in October 2013 provided data on ice thickness and snow depth every 30 min until the system was recovered in May 2014 (for more details see Kirillov et al . []).…”

Observations of flooding and snow‐ice formation in a thinner Arctic sea‐ice regime during the N‐ICE2015 campaign: Influence of basal ice melt and storms

“…Then, there is progressive freezing into snow‐ice as latent heat from solidifying ice is expelled from the flooded snow layer through conductive fluxes in the snow above and ice below (Figure d). Assuming that the mass fractions of snow and water in snow‐ice are 2/3 and 1/3, respectively [ Eicken et al ., ; Kirillov et al ., ], the thickness of slush that turns into snow‐ice at each time t can be estimated as where F s (t) and F i (t) are the conductive heat flux densities in the snow and in the ice at the flooded layer interface at time t, ρ is the ice density (taken as 900), and L the latent heat of fusion. These conductive flux densities (F = –k dT/dz) are calculated with k ≅ 0.3 W m −1 K −1 at the base of the snow [ Yen , ] and k in the ice as in section 2.3.2. The snow‐ice layer thickness H(t) is then estimated as with the time integration running from the time of the flooding t 0 until time t (Figure d).…”