Deterioration of perennial sea ice in the Beaufort Gyre from 2003 to 2012 and its impact on the oceanic freshwater cycle

Time series of ice draft from 2003 to 2012 from moored sonar data are used to investigate variability and describe the reduction of the perennial sea ice cover in the Beaufort Gyre (BG), culminating in the extreme minimum in 2012. Negative trends in median ice drafts and most ice fractions are observed, while open water and thinnest ice fractions (<0.3 m) have increased, attesting to the ablation or removal of the older sea ice from the BG over the 9 year period. Monthly anomalies indicate a shift occurred toward thinner ice after 2007, in which the thicker ice evident at the northern stations was reduced. Differences in the ice characteristics between all of the stations also diminished, so that the ice cover throughout the region became statistically homogenous. The moored data are used in a relationship with satellite radiometer data to estimate ice volume changes throughout the BG. Summer solid fresh water content decreased drastically in consecutive years from 730 km3 in 2006 to 570 km3 in 2007, and to 240 km3 in 2008. After a short rebound, solid fresh water fell below 220 km3 in 2012. Meanwhile, hydrographic data indicate that liquid fresh water in the BG in summer increased 5410 km3 from 2003 to 2010 and decreased at least 210 km3 by 2012. The reduction of both solid and liquid fresh water components indicates a net export of approximately 320 km3 of fresh water from the region occurred between 2010 and 2012, suggesting that the anticyclonic atmosphere-ocean circulation has weakened.

[1]  E. Hansen,et al.  Thinning of Arctic sea ice observed in Fram Strait: 1990–2011 , 2013 .

[2]  D. Cavalieri,et al.  Arctic Sea Ice Variability and Trends, 1979-2006 , 2013 .

[3]  J. Comiso,et al.  On the 2012 record low Arctic sea ice cover: Combined impact of preconditioning and an August storm , 2013 .

[4]  Malcolm Davidson,et al.  CryoSat‐2 estimates of Arctic sea ice thickness and volume , 2013 .

[5]  Stanford B. Hooker,et al.  Pan-Arctic distributions of continental runoff in the Arctic Ocean , 2013, Scientific Reports.

[6]  Jessica Blunden,et al.  State of the Climate in 2011 , 2012 .

[7]  Duncan J. Wingham,et al.  Western Arctic Ocean freshwater storage increased by wind-driven spin-up of the Beaufort Gyre , 2012 .

[8]  Ron Kwok,et al.  Arctic sea ice freeboard from IceBridge acquisitions in 2009: Estimates and comparisons with ICESat , 2012 .

[9]  Ron Kwok,et al.  Changing Arctic Ocean freshwater pathways , 2012, Nature.

[10]  J. Kay,et al.  The Arctic’s rapidly shrinking sea ice cover: a research synthesis , 2012, Climatic Change.

[11]  J. Toole,et al.  The Ice-Tethered Profiler : Argo of the Arctic , 2011 .

[12]  P. Wadhams,et al.  Arctic sea ice thickness characteristics in winter 2004 and 2007 from submarine sonar transects , 2011 .

[13]  R. Kwok,et al.  The thinning of Arctic sea ice , 2011 .

[14]  E. Carmack,et al.  Deepening of the nutricline and chlorophyll maximum in the Canada Basin interior, 2003–2009 , 2010 .

[15]  R. Kwok,et al.  Contribution of melt in the Beaufort Sea to the decline in Arctic multiyear sea ice coverage: 1993–2009 , 2010 .

[16]  Judith Lawton,et al.  Writing up or writing down , 2010 .

[17]  François Massonnet,et al.  Importance of physics, resolution and forcing in hindcast simulations of Arctic and Antarctic sea ice variability and trends , 2010 .

[18]  R. Galley,et al.  Perennial pack ice in the southern Beaufort Sea was not as it appeared in the summer of 2009 , 2009 .

[19]  Ron Kwok,et al.  Thinning and volume loss of the Arctic Ocean sea ice cover: 2003–2008 , 2009 .

[20]  R. Kwok.  Outflow of Arctic Ocean Sea Ice into the Greenland and Barents Seas: 1979-2007 , 2009 .

[21]  Seymour W. Laxon,et al.  Five years of Arctic sea ice freeboard measurements from the Ice, Cloud and land Elevation Satellite , 2009 .

[22]  E. Carmack,et al.  Surface freshening of the Canada Basin, 2003–2007: River runoff versus sea ice meltwater , 2009 .

[23]  E. Carmack,et al.  Beaufort Gyre freshwater reservoir: State and variability from observations , 2009 .

[24]  Seymour W. Laxon,et al.  Circumpolar thinning of Arctic sea ice following the 2007 record ice extent minimum , 2008 .

[25]  J. Toole,et al.  Automated Ice-Tethered Profilers for Seawater Observations under Pack Ice in All Seasons , 2008 .

[26]  Donald K. Perovich,et al.  Sunlight, water, and ice: Extreme Arctic sea ice melt during the summer of 2007 , 2008 .

[27]  R. Galley,et al.  Spatial and temporal variability of sea ice in the southern Beaufort Sea and Amundsen Gulf: 1980–2004 , 2008 .

[28]  Josefino C. Comiso,et al.  Accelerated decline in the Arctic sea ice cover , 2008 .

[29]  M. Vellinga,et al.  The Changing View on How Freshwater Impacts the Atlantic Meridional Overturning Circulation , 2008 .

[30]  E. Carmack,et al.  Freshwater budget of the Canada Basin, Arctic Ocean, from salinity, δ18O, and nutrients , 2008 .

[31]  E. Carmack,et al.  Freshwater Storage in the Northern Ocean and the Special Role of the Beaufort Gyre , 2008 .

[32]  Muyin Wang,et al.  The recent Arctic warm period , 2007 .

[33]  Ron Kwok,et al.  Ice, Cloud, and land Elevation Satellite (ICESat) over Arctic sea ice: Retrieval of freeboard , 2007 .

[34]  Naohiko Hirasawa,et al.  Estimation of Thin Ice Thickness and Detection of Fast Ice from SSM/I Data in the Antarctic Ocean , 2007 .

[35]  S. Uto,et al.  Standardization of electromagnetic–induction measurements of Sea-ice thickness in polar and Subpolar Seas , 2006, Annals of Glaciology.

[36]  Josefino C. Comiso,et al.  Abrupt decline in the Arctic winter sea ice cover , 2006 .

[37]  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.

[38]  H. Melling,et al.  Trends in the draft and extent of seasonal pack ice, Canadian Beaufort Sea , 2005 .

[39]  Ron Lindsay,et al.  The thinning of Arctic sea ice, 1988-2003 : Have we passed a tipping point? , 2005 .

[40]  Ron Kwok,et al.  Estimation of the thin ice thickness and heat flux for the Chukchi Sea Alaskan coast polynya from Special Sensor Microwave/Imager data, 1990–2001 , 2004 .

[41]  J. Vrbancich,et al.  A comparison of the inductive-limit footprints of airborne electromagnetic configurations , 2004 .

[42]  D. Barber,et al.  Meteorological forcing of sea ice concentrations in the southern Beaufort Sea over the period 1979 to 2000 , 2004 .

[43]  Mark A. Johnson,et al.  Arctic decadal variability: An auto‐oscillatory system of heat and fresh water exchange , 2004 .

[44]  Neil Peacock,et al.  High interannual variability of sea ice thickness in the Arctic region , 2003, Nature.

[45]  J. Vrbancich,et al.  Shipborne electromagnetic measurements of Antarctic sea‐ice thickness , 2003 .

[46]  Kay I. Ohshima,et al.  Variability of sea‐ice draft off Hokkaido in the Sea of Okhotsk revealed by a moored ice‐profiling sonar in winter of 1999 , 2003 .

[47]  A. Proshutinsky,et al.  The role of the Beaufort Gyre in Arctic climate variability: Seasonal to decadal climate scales , 2002 .

[48]  Shotaro Uto,et al.  Sea ice thickness estimated from passive microwave radiometers , 2002 .

[49]  N. Kimura,et al.  Processes controlling the advance and retreat of sea ice in the Sea of Okhotsk , 1999 .

[50]  Seelye Martin,et al.  The production of ice and dense shelf water in the Okhotsk Sea polynyas , 1998 .

[51]  Douglas M. Smith,et al.  Observation of perennial Arctic sea ice melt and freeze-up using passive microwave data , 1998 .

[52]  V. Strass,et al.  Measuring sea ice draft and coverage with moored upward looking sonars , 1998 .

[53]  Marvin L. Johnson,et al.  Two circulation regimes of the wind-driven Arctic Ocean , 1997 .

[54]  A. Kovacs.  Sea ice. Part 1, Bulk salinity versus ice floe thickness , 1996 .

[55]  Humfrey Melling,et al.  Development of seasonal pack ice in the Beaufort Sea during the winter of 1991–1992: A view from below , 1996 .

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

[57]  H. Melling,et al.  The underside topography of sea ice over the continental shelf of the Beaufort Sea in the winter of 1990 , 1995 .

[58]  Humfrey Melling,et al.  Measurements of the Underside Topography of Sea Ice by Moored Subsea Sonar , 1995 .

[59]  Donald J. Cavalieri,et al.  A microwave technique for mapping thin sea ice , 1994 .

[60]  Richard K. Moore,et al.  Radar remote sensing and surface scattering and emission theory , 1986 .

[61]  W. Campbell,et al.  Determination of sea ice parameters with the NIMBUS 7 SMMR , 1984 .

[62]  Richard K. Moore,et al.  Microwave Remote Sensing, Active and Passive , 1982 .

[63]  P. Wadhams,et al.  An Analysis Of Ice Profiles Obtained By Submarine Sonar In The Beaufort Sea , 1980, Journal of Glaciology.

[64]  J. Jacobs,et al.  WMO Sea-Ice Nomenclature , 1972 .