Seasonal evolution of an ice‐shelf influenced fast‐ice regime, derived from an autonomous thermistor chain

Ice shelves strongly interact with coastal Antarctic sea ice and the associated ecosystem by creating conditions favorable to the formation of a sub-ice platelet layer. The close investigation of this phenomenon and its seasonal evolution remains a challenge due to logistical constraints and a lack of suitable methodology. In this study, we characterize the seasonal cycle of Antarctic fast ice adjacent to the Ekstrom Ice Shelf in the eastern Weddell Sea. We used a thermistor chain with the additional ability to record the temperature response induced by cyclic heating of resistors embedded in the chain. Vertical sea-ice temperature and heating profiles obtained daily between November 2012 and February 2014 were analyzed to determine sea-ice and snow evolution, and to calculate the basal energy budget. The residual heat flux translated into an ice-volume fraction in the platelet layer of 0.18 ± 0.09, which we reproduced by a independent model simulation and agrees with earlier results. Manual drillings revealed an average annual platelet-layer thickness increase of at least 4 m, and an annual maximum thickness of 10 m beneath second-year sea ice. The oceanic contribution dominated the total sea-ice production during the study, effectively accounting for up to 70% of second-year sea-ice growth. In summer, an oceanic heat flux of 21 W m−2 led to a partial thinning of the platelet layer. Our results further show that the active heating method, in contrast to the acoustic sounding approach, is well suited to derive the fast-ice mass balance in regions influenced by ocean/ice-shelf interaction, as it allows subdiurnal monitoring of the platelet-layer thickness.

[1]  D. Perovich,et al.  Temporal evolution of Arctic sea-ice temperature , 2001, Annals of Glaciology.

[2]  Hajo Eicken,et al.  Development and properties of sea ice in the coastal regime of the southeastern Weddell Sea , 1989 .

[3]  Keran Claffey,et al.  Ice mass-balance buoys: a tool for measuring and attributing changes in the thickness of the Arctic sea-ice cover , 2006, Annals of Glaciology.

[4]  Y. Yen.  Review of Thermal Properties of Snow, Ice and Sea Ice, , 1981 .

[5]  R. Bintanja,et al.  The effect of increased fresh water from Antarctic ice shelves on future trends in Antarctic sea ice , 2015, Annals of Glaciology.

[6]  T. Fichefet,et al.  Antarctic ice‐sheet melting provides negative feedbacks on future climate warming , 2008 .

[7]  Shotaro Uto,et al.  Characteristics of Sea-ice thickness and Snow-depth distributions of the Summer landfast ice in Lützow-Holm Bay, East Antarctica , 2006, Annals of Glaciology.

[8]  M. Paget,et al.  Effects of regional fast-ice and iceberg distributions on the behaviour of the Mertz Glacier polynya, East Antarctica , 2001, Annals of Glaciology.

[9]  J. Kipfstuhl.  Zur Entstehung von Unterwassereis und das Wachstum und die Energiebilanz des Meereises in der Atka Bucht, Antarktis = On the formation of underwater ice and the growth and energy budget of the sea ice in Atka Bay, Antarctica , 1991 .

[10]  Bert Wouters,et al.  Important role for ocean warming and increased ice-shelf melt in Antarctic sea-ice expansion , 2013 .

[11]  D. Qin,et al.  Structure, salinity and isotopic composition of multi-year landfast sea ice in Nella Fjord, Antarctica , 2007 .

[12]  S. Stammerjohn,et al.  Trends in Antarctic annual sea ice retreat and advance and their relation to El Niño–Southern Oscillation and Southern Annular Mode variability , 2008 .

[13]  H. Hellmer,et al.  Antarctic Ice Sheet melting in the southeast Pacific , 1996 .

[14]  Terhikki Manninen,et al.  The brine and gas content of sea ice with attention to low salinities and high temperatures , 1988 .

[15]  P. Langhorne,et al.  Observation and modeling of platelet ice fabric in McMurdo Sound, Antarctica , 2010 .

[16]  M. Jeffries,et al.  Structural characteristics of congelation and platelet ice and their role in the development of antarctic land-fast sea ice , 1993, Journal of Glaciology.

[17]  Jinlun Zhang,et al.  Increasing Antarctic Sea Ice under Warming Atmospheric and Oceanic Conditions , 2007 .

[18]  P. Langhorne,et al.  Sea ice growth rates near ice shelves , 2012 .

[19]  S. Gerland,et al.  An Antarctic monitoring initiative for fast ice and comparison with the Arctic , 2011 .

[20]  J. Tison,et al.  Linking Landfast Sea Ice Variability to Marine Ice Accretion at Hells Gate Ice Shelf, Ross Sea , 2013 .

[21]  N. Welschmeyer.  Fluorometric analysis of chlorophyll a in the presence of chlorophyll b and pheopigments , 1994 .

[22]  Lars Kindermann,et al.  Real-Time Underwater SoundsFrom the Southern Ocean , 2006 .

[23]  Matthew Sturm,et al.  Thermal conductivity measurements of depth hoar , 1992 .

[24]  E. Gerber,et al.  Impacts of the north and tropical Atlantic Ocean on the Antarctic Peninsula and sea ice , 2014, Nature.

[25]  Ron Kwok,et al.  Wind-driven trends in Antarctic sea-ice drift , 2012 .

[26]  K. Ohshima,et al.  Current variability under landfast sea ice in Lützow‐Holm Bay, Antarctica , 2000 .

[27]  Marcel Nicolaus,et al.  The impact of early-summer snow properties on Antarctic landfast sea-ice X-band backscatter , 2015, Annals of Glaciology.

[28]  A. E. Perry,et al.  Hot-Wire Anemometry , 1982 .

[29]  J. Fyfe,et al.  The influence of recent Antarctic ice sheet retreat on simulated sea ice area trends , 2013 .

[30]  Rüdiger Gerdes,et al.  Towards an estimation of sub-sea-ice platelet-layer volume with multi-frequency electromagnetic induction sounding , 2015, Annals of Glaciology.

[31]  N. Untersteiner,et al.  On the mass and heat budget of arctic sea ice , 1961 .

[32]  J. Eastman,et al.  The role of notothenioid fish in the food web of the Ross Sea shelf waters: a review , 2004, Polar Biology.

[33]  P. Langhorne,et al.  Evolution of a supercooled Ice Shelf Water plume with an actively growing subice platelet matrix , 2014 .

[34]  Donald J. Cavalieri,et al.  Antarctic sea ice variability and trends, 1979-2010 , 2012 .

[35]  D. H. Robinson,et al.  A high resolution study of the platelet ice ecosystem in McMurdo Sound, Antarctica photosynthetic and bio-optical characteristics of a dense microalgal bloom , 1993 .

[36]  Chris Petrich,et al.  Modelling the interrelationships between permeability, effective porosity and total porosity in sea ice , 2006 .

[37]  P. Langhorne,et al.  Growth of first-year landfast Antarctic sea ice determined from winter temperature measurements , 2006, Annals of Glaciology.

[38]  P. Langhorne,et al.  Platelet ice and the land-fast sea ice of McMurdo Sound, Antarctica , 2001, Annals of Glaciology.

[39]  Martin Schneebeli,et al.  Thermal conductivity of snow measured by three independent methods and anisotropy considerations , 2013 .

[40]  P. Heil,et al.  Seasonal and interannual variations of the oceanic heat flux under a landfast Antarctic sea ice cover , 1996 .

[41]  M. Vacchi,et al.  The Coastal Fish Fauna of Terra Nova Bay, Ross Sea, Antarctica , 2000 .

[42]  Hajo Eicken,et al.  Thermal conductivity of landfast Antarctic and Arctic sea ice , 2007 .

[43]  K. Ohshima,et al.  Physical, structural, and isotopic characteristics and growth processes of fast sea ice in Lützow‐Holm Bay, Antarctica , 1997 .

[44]  E. Lewis,et al.  Ice pumps and their rates , 1986 .

[45]  M. Labarbera,et al.  An inexpensive thermistor flowmeter for aquatic biology1 , 1976 .

[46]  A. Semtner.  A MODEL FOR THE THERMODYNAMIC GROWTH OF SEA ICE IN NUMERICAL INVESTIGATIONS OF CLIMATE , 1975 .

[47]  P. Langhorne,et al.  The seasonal appearance of ice shelf water in coastal Antarctica and its effect on sea ice growth , 2011 .

[48]  Garry Timco,et al.  A review of sea ice density , 1996 .

[49]  H. Hellmer,et al.  The occurrence of ice platelets at 250 m depth near the Filchner Ice Shelf and its significance for sea ice biology , 1986 .

[50]  L. Fuiman,et al.  Hunting behavior of a marine mammal beneath the antarctic fast Ice , 1999, Science.

[51]  Gert König-Langlo,et al.  The Meteorological Observatory at Neumayer Stations (GvN and NM-II) Antarctica , 2007 .

[52]  Judith A. Curry,et al.  Interpretation of recent Antarctic sea ice variability , 2004 .

[53]  P. Langhorne,et al.  Signatures of supercooling: McMurdo Sound platelet ice , 2012, Journal of Glaciology.

[54]  J. Curry,et al.  Accelerated warming of the Southern Ocean and its impacts on the hydrological cycle and sea ice , 2010, Proceedings of the National Academy of Sciences.

[55]  G. König‐Langlo,et al.  Climatology of the three coastal Antarctic stations Dumont D'urville, Neumayer and Halley , 1998 .

[56]  H. Goosse,et al.  An analysis of the atmospheric processes driving the large-scale winter sea ice variability in the Southern Ocean , 2008 .

[57]  Bin Cheng,et al.  Annual cycle of landfast sea ice in Prydz Bay, east Antarctica , 2010 .

[58]  William H. Lipscomb,et al.  An energy-conserving thermodynamic model of sea ice , 1999 .

[59]  S. Hendricks,et al.  Changes in Arctic sea ice result in increasing light transmittance and absorption , 2012 .

[60]  M. Maqueda,et al.  Modelling the influence of snow accumulation and snow-ice formation on the seasonal cycle of the Antarctic sea-ice cover , 1999 .

[61]  Gerhard Dieckmann,et al.  Seasonal development of algal biomass in snow-covered fast ice and the underlying platelet layer in Atka Bay, Antarctica , 1999 .

[62]  M. Vacchi,et al.  Early life stages in the life cycle of Antarctic silverfish, Pleuragramma antarcticum in Terra Nova Bay, Ross Sea , 2004, Antarctic Science.

[63]  D. Thompson,et al.  Seasonal Relationships between Large-Scale Climate Variability and Antarctic Sea Ice Concentration , 2012 .

[64]  S. Nghiem,et al.  Seasonal evolution and interannual variability of the local solar energy absorbed by the Arctic sea ice–ocean system , 2007 .

[65]  J. Lilly,et al.  Two years of oceanic observations below the Fimbul Ice Shelf, Antarctica , 2012 .

[66]  E. Fahrbach,et al.  Flow of bottom water in the northwestern Weddell Sea , 2001 .

[67]  Gerhard Dieckmann,et al.  Biogeochemistry of antarctic sea ice : a case study on platelet ice layers at Drescher Inlet, Weddell Sea , 1999 .

[68]  P. Heil.  Atmospheric conditions and fast ice at Davis, East Antarctica: A case study , 2006 .

[69]  N. Untersteiner,et al.  Using sea ice to measure vertical heat flux in the ocean , 1982 .

[70]  Gerhard Dieckmann,et al.  Vertical zonation and community transition of sea-ice diatoms in fast ice and platelet layer, Weddell Sea, Antarctica , 2001, Annals of Glaciology.

[71]  A. Fraser,et al.  East Antarctic Landfast Sea Ice Distribution and Variability, 2000–08 , 2012 .

[72]  Ted Maksym,et al.  A Novel and Low-Cost Sea Ice Mass Balance Buoy , 2013 .

[73]  Bin Cheng,et al.  Multiyear sea ice thermal regimes and oceanic heat flux derived from an ice mass balance buoy in the Arctic Ocean , 2014 .

[74]  G. Leonard,et al.  Anchor ice in polar oceans , 2013 .

[75]  S. Willmes,et al.  Ice platelets below Weddell Sea landfast sea ice , 2015, Annals of Glaciology.