scholarly journals Growth of first-year landfast Antarctic sea ice determined from winter temperature measurements

2006 ◽  
Vol 44 ◽  
pp. 170-176 ◽  
Author(s):  
Craig R. Purdie ◽  
Patricia J. Langhorne ◽  
Greg H. Leonard ◽  
Tim G. Haskell
Keyword(s):  
Heat Flux ◽  
Sea Ice ◽  
Ice Cores ◽  
First Year ◽  
Conductive Heat ◽  
Ice Growth ◽  
Antarctic Sea Ice ◽  
Oceanic Heat Flux ◽  
Landfast Sea Ice ◽  
Platelet Ice

AbstractTemperature profiles of first-year landfast sea ice have been recorded continuously over the 2003 winter growth season at McMurdo Sound, Antarctica. The temperature gradients in the ice were used to calculate the growth rate due to conductive heat flux, which is shown to account for only part of the total ice growth. Remaining ice growth must be due to a negative oceanic heat flux. Significantly, this oceanic heat flux is shown to occur episodically, sometimes with sustained daily rates in excess of –30Wm–2. There is no direct correlation between oceanic heat flux and water temperature. Times of increased oceanic heat flux do coincide with the appearance of platelet ice in cores, and appear to account for the growth of 35% of the total platelet ice depth measured in ice cores.

scholarly journals Oceanic Heat Flux as a Component of the Heat Budget of Sea Ice

1985 ◽  
Vol 6 ◽  
pp. 171-173 ◽  
Author(s):  
M. P. Langleben
Keyword(s):  
Heat Flux ◽  
Sea Ice ◽  
Latent Heat ◽  
Heat Budget ◽  
Average Rate ◽  
Ice Cores ◽  
Ice Cover ◽  
Energy Balance Equation ◽  
Conductive Heat ◽  
Oceanic Heat Flux

Heat budget studies of the sea ice cover near Pond Inlet, NWT, were made using data obtained at two locations in Eclipse Sound, one about 0.5 km from shore and the other about 7.5 km from shore. The observations at intervals of one week included ice temperatures at 10 cm separation in vertical profile, salinities of adjacent 2.5 cm-thick slices from vertical ice cores, and ice thickness. The time series analysed extend from three to six months in the six data sets obtained for three winters of observations. Values of oceanic heat flux have been determined as residuals in the energy balance equation applied to the ice cover. The results show that in Eclipse Sound the oceanic heat flux is a significant component of the heat budget of the ice cover. Its value over the winter is typically about 6 W m-2about half as large as the average rate of release of the latent heat of freezing. There does not appear to be any systematic variation in value of the 4 week-average oceanic heat flux during the season. Nor is there any apparent correlation of oceanic heat flux with rate of release of latent heat (ie ice growth rate), or with the severity of the winter as measured by the magnitude of the conductive heat flux.

scholarly journals Oceanic Heat Flux as a Component of the Heat Budget of Sea Ice

1985 ◽  
Vol 6 ◽  
pp. 171-173
Author(s):  
M. P. Langleben
Keyword(s):  
Heat Flux ◽  
Sea Ice ◽  
Latent Heat ◽  
Heat Budget ◽  
Average Rate ◽  
Ice Cores ◽  
Ice Cover ◽  
Energy Balance Equation ◽  
Conductive Heat ◽  
Oceanic Heat Flux

Heat budget studies of the sea ice cover near Pond Inlet, NWT, were made using data obtained at two locations in Eclipse Sound, one about 0.5 km from shore and the other about 7.5 km from shore. The observations at intervals of one week included ice temperatures at 10 cm separation in vertical profile, salinities of adjacent 2.5 cm-thick slices from vertical ice cores, and ice thickness. The time series analysed extend from three to six months in the six data sets obtained for three winters of observations. Values of oceanic heat flux have been determined as residuals in the energy balance equation applied to the ice cover. The results show that in Eclipse Sound the oceanic heat flux is a significant component of the heat budget of the ice cover. Its value over the winter is typically about 6 W m-2 about half as large as the average rate of release of the latent heat of freezing. There does not appear to be any systematic variation in value of the 4 week-average oceanic heat flux during the season. Nor is there any apparent correlation of oceanic heat flux with rate of release of latent heat (ie ice growth rate), or with the severity of the winter as measured by the magnitude of the conductive heat flux.

scholarly journals An Isotopic Method of Estimating Conductive Heat Flux Through Antarctic First-Year Sea Ice

1990 ◽  
Vol 14 ◽  
pp. 270-272 ◽  
Author(s):  
R. Souchez ◽  
J. -L. Tison ◽  
J. Jouzel
Keyword(s):  
Heat Flux ◽  
Growth Rate ◽  
Sea Ice ◽  
Growth Period ◽  
Ice Cover ◽  
Rate Curve ◽  
First Year ◽  
Conductive Heat ◽  
Antarctic Sea Ice ◽  
Conductive Heat Flux

The deuterium concentration profile in a first-year Antarctic sea-ice cover is used to deduce a growth-rate curve, applying a previously published model. Time variations of the conductive heat flux throughout the growth period are then estimated from this growth-rate curve. Results indicate that the isotopic determination of sea ice growth rate can be considered as an alternate method for determining the conductive heat flux through a young sea-ice cover. However, there is need for a further test of the method by measuringin situtemperatures and growth rates during the formation of first-year sea ice, and by analyzing the isotopic composition of ice samples taken simultaneously along selected profiles during the growth period.

scholarly journals An Isotopic Method of Estimating Conductive Heat Flux Through Antarctic First-Year Sea Ice

1990 ◽  
Vol 14 ◽  
pp. 270-272
Author(s):  
R. Souchez ◽  
J. -L. Tison ◽  
J. Jouzel
Keyword(s):  
Heat Flux ◽  
Growth Rate ◽  
Sea Ice ◽  
Growth Period ◽  
Ice Cover ◽  
Rate Curve ◽  
First Year ◽  
Conductive Heat ◽  
Antarctic Sea Ice ◽  
Conductive Heat Flux

The deuterium concentration profile in a first-year Antarctic sea-ice cover is used to deduce a growth-rate curve, applying a previously published model. Time variations of the conductive heat flux throughout the growth period are then estimated from this growth-rate curve. Results indicate that the isotopic determination of sea ice growth rate can be considered as an alternate method for determining the conductive heat flux through a young sea-ice cover. However, there is need for a further test of the method by measuring in situ temperatures and growth rates during the formation of first-year sea ice, and by analyzing the isotopic composition of ice samples taken simultaneously along selected profiles during the growth period.

Seasonal evolution and salt/freshwater fluxes of first-year sea ice: Comparison between pack ice and landfast sea ice 

2021 ◽  
Author(s):  
Marc Oggier ◽  
Hajo Eicken ◽  
Robert Rember ◽  
Allison Fong ◽  
Dmitry V. Divine ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ice Cores ◽  
Upper Ocean ◽  
First Year ◽  
Ice Melt ◽  
Ice Surface ◽  
Freshwater Fluxes ◽  
Exchange Processes ◽  
Bulk Salinity ◽  
Landfast Sea Ice

<p>Sea ice affects the exchange of energy and matter between the atmosphere and the ocean from local to hemispheric scales. Salt fluxes across the ice-ocean interface that drive thermohaline mixing beneath growing sea ice are important elements of upper ocean nutrient and carbon exchange. Sea-ice melt releases freshwater into the upper ocean and results in formation of melt ponds that affect gas and energy transfer across the atmosphere-ice interface. The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) provided an opportunity to follow sea-ice evolution and exchange processes over a full seasonal cycle in a rapidly changing ice cover. To this end, approximately 25 sea-ice cores were collected at 2 distinct sites, representing first-year and multi-year ice, to monitor physical, biological and geochemical processes relevant to atmosphere-ice-ocean exchange processes. Here we compare the growth and decay of first-year ice in the Central Arctic during the winter 2019-2020 to that of landfast first-year ice at Utqiaġvik, Alaska, from 1998 to 2016. Ice stratigraphy was similar at both sites with about 15 cm of granular ice on top of columnar ice, with a comparable growth history with a similar maximum ice thickness of 1.6-1.7 m. We aggregated the sea-ice bulk salinity and temperature profiles using a degree-day approach, and examined brine and freshwater fluxes at lower and upper interfaces of the ice, respectively. Preliminary results show lower sea-ice bulk salinity during the growth season and greater desalination at the ice surface during the melt season at the MOSAiC floe in comparison to Utqiaġvik.</p>

scholarly journals Dissolved organic matter in Antarctic sea ice

2001 ◽  
Vol 33 ◽  
pp. 297-303 ◽  
Author(s):  
David N. Thomas ◽  
Gerhard Kattner ◽  
Ralph Engbrodt ◽  
Virginia Giannelli ◽  
Hilary Kennedy ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Sea Ice ◽  
Pore Space ◽  
Ice Cores ◽  
Weddell Sea ◽  
Poor Correlation ◽  
First Year ◽  
Mean Values ◽  
Antarctic Sea Ice

AbstractIt has been hypothesized that there are significant dissolved organic matter (DOM) pools in sea-ice systems, although measurements of DOM in sea ice have only rarely been made. The significance of DOM for ice-based productivity and carbon turnover therefore remains highly speculative. DOM within sea ice from the Amundsen and Bellingshausen Seas, Antarctica, in 1994 and the Weddell Sea, Antarctica, in 1992 and 1997 was investigated. Measurements were made on melted sea-ice sections in 1994 and 1997 and in sea-ice brines in 1992. Dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) concentrations in melted ice cores were up to 1.8 and 0.78 mM, respectively, or 30 and 8 times higher than those in surface water concentrations, respectively. However, when concentrations within the brine channel/pore space were calculated from estimated brine volumes, actual concentrations of DOC in brines were up to 23.3 mM and DON up to 2.2 mM, although mean values were 1.8 and 0.15 mM, respectively. There were higher concentrations of DOM in warm, porous summer second-year sea ice compared with colder autumn first-year ice, consistent with the different biological activity supported within the various ice types. However, in general there was poor correlation between DOC and DON with algal biomass and numbers of bacteria within the ice. The mean DOC/DON ratio was 11, although again values were highly variable, ranging from 3 to highly carbon-enriched samples of 95. Measurements made on a limited dataset showed that carbohydrates constitute on average 35% of the DOC pool, with highly variable contributions of 1−99%.

scholarly journals Seasonal changes of sea-ice characteristics off East Antarctica

1994 ◽  
Vol 20 ◽  
pp. 195-201 ◽  
Author(s):  
Ian Allison ◽  
Anthony Worby
Keyword(s):  
Sea Ice ◽  
Ice Cores ◽  
Open Water ◽  
Ice Formation ◽  
Ice Thickness ◽  
Spatial And Temporal Variability ◽  
Growth Season ◽  
Ice Growth ◽  
Antarctic Sea Ice ◽  
Ice Edge

Data on Antarctic sea‐ice characteristics, and their spatial and temporal variability, are presented from cruises between 1986 and 1993 for the region spanning 60°−150° E between October and May. In spring, the sea‐ice zone is a variable mixture of different thicknesses of ice plus open water and in some regions only 30−40% of the area is covered with ice >0.3 m thick. The thin‐ice and open‐water areas are important for air‐sea heat exchange. Crystallographic analyses of ice cores, supported by salinity and stable‐isotope measurements, show that approximately 50% of the ice mass is composed of small frazil crystals. These are formed by rapid ice growth in leads and polynyas and indicate the presence of open water throughout the growth season. The area‐averaged thickness of undeformed ice west of 120° E is typically less than 0.3 m and tends to‐increase with distance south of the ice edge. Ice growth by congelation freezing rarely exceeds 0.4 m, with increases in ice thickness beyond this mostly attributable to rafting and ridging. While most of the total area is thin ice or open water, in the central pack much of the total ice mass is contained in ridges. Taking account of the extent of ridging, the total area‐averaged ice thickness is estimated to be about 1m for the region 60°−90° E and 2 m for the region 120°−150° E. By December, new ice formation has ceased in all areas of the pack and only floes >0.3 m remain. In most regions these melt completely over the summer and the new season's ice formation starts in late February. By March, the thin ice has reached a thickness of 0.15 0.30 m, with nilas formation being an important mechanism for ice growth within the ice edge

scholarly journals Observations and modelling of first-year ice growth and simultaneous second-year ice ablation in the Prydz Bay, East Antarctica

2017 ◽  
Vol 58 (75pt1) ◽  
pp. 59-67 ◽  
Author(s):  
Jiechen Zhao ◽  
Bin Cheng ◽  
Qinghua Yang ◽  
Timo Vihma ◽  
Lin Zhang
Keyword(s):  
Heat Flux ◽  
Temperature Gradient ◽  
East Antarctica ◽  
Prydz Bay ◽  
Large Temperature ◽  
First Year ◽  
Conductive Heat ◽  
Oceanic Heat Flux ◽  
Conductive Heat Flux ◽  
Second Year

ABSTRACT The seasonal cycle of fast ice thickness in Prydz Bay, East Antarctica, was observed between March and December 2012. In March, we observed a 0.16 m thickness gain of 0.22 m-thick first-year ice (FYI), while 1.16 m-thick second-year ice (SYI) nearby simultaneously ablated by 0.59 m. A 1-D thermodynamic sea-ice model was applied to identify the factors that led to the simultaneous growth of FYI and melt of SYI. The different evolutions were explained by the difference in the conductive heat flux between the FYI and SYI. As the FYI was thin, there was a large temperature gradient between the ice base and the colder ice surface. This generated an upward conductive heat flux, which was larger than the heat flux from the ocean to the ice base, yielding basal growth of ice. In the case of the thicker SYI the temperature gradient and, hence, the conductive heat flux were smaller, and not sufficient to balance the oceanic heat flux at the ice base, yielding basal ablation. Penetration of solar radiation affected the conductive heat flux in both cases, and the model results were sensitive to the initial ice temperature profile and the uncertainty of the oceanic heat flux.

scholarly journals Measurements of turbulence transfer in the near-surface layer over the Antarctic sea-ice surface from April through November in 2016

2020 ◽  
Vol 61 (82) ◽  
pp. 12-23
Author(s):  
Changwei Liu ◽  
Zhiqiu Gao ◽  
Qinghua Yang ◽  
Bo Han ◽  
Hong Wang ◽  
...  
Keyword(s):  
Heat Flux ◽  
Sea Ice ◽  
Roughness Length ◽  
Sensible Heat Flux ◽  
Surface Energy Budget ◽  
The Arctic ◽  
Conductive Heat ◽  
Near Surface ◽  
Antarctic Sea Ice ◽  
The Antarctic

AbstractThe surface energy budget over the Antarctic sea ice from 8 April 2016 through 26 November 2016 are presented. From April to October, Sensible heat flux (SH) and subsurface conductive heat flux (G) were the heat source of surface while latent heat flux (LE) and net radiation flux (Rn) were the heat sink of surface. Our results showed larger downward SH (due to the warmer air in our site) and upward LE (due to the drier air and higher wind speed in our site) compared with SHEBA data. However, the values of SH in N-ICE2015 campaign, which located at a zone with stronger winds and more advection of heat in the Arctic, were comparable to our results under clear skies. The values of aerodynamic roughness length (z0m) and scalar roughness length for temperature (z0h), being 1.9 × 10−3 m and 3.7 × 10−5 m, were suggested in this study. It is found that snow melting might increase z0m. Our results also indicate that the value of log(z0h/z0m) was related to the stability of stratification. In addition, several representative parameterization schemes for z0h have been tested and a couple of schemes were found to make a better performance.

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