Brine Convection, Temperature Fluctuations, and Permeability in Winter Antarctic Land‐Fast Sea Ice

Abstract

Vertical temperature strings are used in sea ice research to study heat flow, ice growth rate, and ocean‐ice‐atmosphere interaction. We demonstrate the feasibility of using temperature fluctuations as a proxy for fluid movement, a key process for supplying nutrients to Antarctic sea ice algal communities. Four strings were deployed in growing, land‐fast sea ice in McMurdo Sound, Antarctica. By smoothing temperature data with the robust LOESS method, we obtain temperature fluctuations that cannot be explained by insolation or atmospheric heat loss. Statistical distributions of these temperature fluctuations are investigated with sensitivities to the distance from the ice‐ocean interface, average ice temperature, and sea ice structure. Fluctuations are greatest close to the base (<50 mm) at temperatures >−3°C, and are discrete events with an average active period of 43% compared to 11% when the ice is colder (–3°C to −5°C). Assuming fluctuations occur when the Rayleigh number, derived from mushy layer theory, exceeds a critical value of 10 we approximate the harmonic mean permeability of this thick (>1 m) sea ice in terms of distance from the ice‐ocean interface. Near the base, we obtain values in the same range as those measured by others in Arctic spring and summer. The permeability between the ice‐ocean interface and 0.05 ± 0.04 m above it is of order 10−9 m2. Columnar and incorporated platelet ice permeability distributions in the bottom 0.1 m of winter Antarctic sea ice are statistically significantly different although their arithmetic means are indistinguishable.

Platelet ice, the Southern Ocean's hidden ice: a review

“…This is a subtle effect that is not clearly obvious in the C-shaped salinity profiles from single cores (Smith and others, 2012). Wongpan and others (2018a) showed that this is the result of the arithmetic mean permeability for columnar and incorporated platelet ice being indistinguishable beneath thick Antarctic landfast sea ice, implying that porosity is more important than crystal geometry. It should be noted that Wongpan and others (2018a) were only able to probe incorporated platelet ice which has a porosity similar to columnar sea ice.…”

“…Wongpan and others (2018a) showed that this is the result of the arithmetic mean permeability for columnar and incorporated platelet ice being indistinguishable beneath thick Antarctic landfast sea ice, implying that porosity is more important than crystal geometry. It should be noted that Wongpan and others (2018a) were only able to probe incorporated platelet ice which has a porosity similar to columnar sea ice. Less is known of the sub-ice platelet layer which has been measured to be isothermal.…”

An Overview on the Treatment and Management of the Desalination Brine Solution

“…This process can also provide the required nutrients for the plants. Different factors are affecting the selection of this option such as the existence and price of the land, expenses related to water dilution, cost of the irrigation equipment, infiltration rates, irrigation importance, salinity tolerance interval for desired vegetation, and groundwater quality regulations [53]. Based on the Food and Agriculture Organization (FAO) of the United Nations [54], the regulated concentration limits of Ca, Mg, and Na ions to irrigate the general crops are 400, 60, and 900 mg L −1 , respectively.…”

Strain response and energy dissipation of floating saline ice under cyclic compressive stress

“…7a, σ max and σ min represent the upper and the lower bounds of the cyclic compressive stress, respectively, and T denotes the period for one loading cycle. As indicated by Table 1, six periods ranging from 1 to 10 3 s were employed; these periods cover the main range of ocean wave periods, which usually vary from several seconds to tens of seconds (Reistad et al, 2011;Zijlema et al, 2012). In each dry test, only a fixed frequency was applied.…”

“…The latter point is important to address in experimentation and modeling. The temperature gradient is implicitly taken into account when performing in situ experiments on floating ice (Langhorne et al, 2015;Wongpan et al, 2018). The cost of in situ experimental campaigns, however, is high, and the experiments often require specially designed loading devices (Vincent and Dempsey, 1999;Dempsey et al, 1999Dempsey et al, , 2018Cole and Dempsey, 2004).…”