ACCESS NUMBER: TO-15174

STUDY TITLE: Beaufort and Chukchi Sea Seasonal Variability for Two Arctic Climate States 

REPORT TITLE: Beaufort and Chukchi Sea Seasonal Variability for Two Arctic Climate States 

CONTRACT NUMBER: 1435-01-98-CA 30909; TASK ORDER (TO): 15174 

SPONSORING OCS REGION: Alaska 

APPLICABLE PLANNING AREA: Beaufort and Chukchi seas 

FISCAL YEAR OF PROJECT FUNDING: 1999 

COMPLETION DATE OF REPORT: May 2003 

COST: FY 1999: $281,918; CUMULATIVE PROJECT COST: $281,918 

PROJECT MANAGER: Andrey Y. Proshutinsky 

AFFILIATION: Woods Hole Oceanographic Institution 

ADDRESS: Physical Oceanography Department, MS #29, Woods Hole Oceanographic 

Institution, Woods Hole, MA 02543 

PRINCIPAL INVESTIGATORS*: Andrey Y. Proshutinsky, Mark A. Johnson 

KEY WORDS: Chukchi and Beaufort seas, ocean, atmosphere, sea ice 

BACKGROUND: 

Arctic navigation, oil and gas exploration, and arctic pollutant transport depend on arctic 

environmental conditions. Existing atlases, manuals, and reference books contain multi-year 

mean environmental variables and their multi-year mean seasonal variability; however, 

uncertainties result from the existing atlases because they do not take into account climate 

change and climate variability. The work was motivated by the recent finding of two regimes of 

arctic atmosphere–ice–ocean circulation described by Proshutinsky and Johnson in 1997. It was 

expected that seasonal variations in the ice concentration, ice thickness, and ice drift; ocean 

currents, ocean temperature, and salinity; atmospheric pressure, wind speed, cloudiness, and 

precipitation; river discharge; and permafrost temperatures are different for cyclonic and 

anticyclonic regimes. The major goal of this research was to document the atmospheric, ice, and 

oceanic signals showing seasonal variability of environmental parameters during cyclonic and 

anticyclonic climate regimes in the Beaufort and Chukchi seas. 

OBJECTIVES: 

The project goals were to: 1) do a quality control of the existing data and analyze temporal and 

spatial variability of the environmental fields at seasonal and interannual time scales, 2) average 

existing data for the periods of cyclonic and anticyclonic regimes of circulation, and 3) calculate 

differences between the anticyclonic and cyclonic regimes in the major parameters characterizing 

atmospheric, sea ice, and oceanic conditions. 

DESCRIPTION: 

We have documented the atmospheric, ice, and oceanic signals showing seasonal variability of 

environmental parameters during cyclonic and anticyclonic climate regimes in the Beaufort and 

Chukchi seas using environmental data from national and international data centers and results 

of numerical modeling experiments specially designed for these studies. 
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The annual variability of the Beaufort and Chukchi seas is characterized by a large seasonal 

cycle against a background of climatically significant interannual and decadal time-scale 

variations. One of the most significant of these interannual variations is wind-driven motion in the 

upper Beaufort Gyre which alternates between anticyclonic and cyclonic. This study has focused 

on differences in the seasonal cycle in years attributed to the cyclonic circulation regime (CCR 

years: 1953–1957, 1964–1971, 1980–1983, 1989–1997) and the anticyclonic circulation regime 

(ACCR years: 1946–1952, 1958–1963, 1972–1979, 1984–1988, and 1998-present), and the 

possible impact these seasonal anomalies have on fluctuations occurring over longer durations. 

Atmospheric, ice, and oceanic observational data and the results of numerical experiments with a 

coupled sea ice–ocean model provide evidence that during the ACCR the arctic atmospheric 

pressure is higher and wind speed is lower compared with the CCR. A mean arctic ACCR winter 

is colder than a mean CCR winter. When the CCR dominates, precipitation increases over the 

ocean and decreases over the land. During the CCR, summer wind divergence effectively 

produces numerous sea-ice openings. Repetition of this cyclonic process over several years 

results in overall thinner ice in the central Arctic, compared with that during the ACCR. Under the 

CCR, more ice-free summer areas lead to an accumulation of additional heat in the upper ocean, 

resulting in longer periods of ice melt, an increase in fresher water content, and thinner ice. In 

CCR years both dynamical and thermodynamical factors cause excess ice and freshwater 

transport from the Beaufort Sea through the Canadian Archipelago Straits. The freshwater 

storage within the Arctic Ocean results in a persistent salinity anomaly in the Beaufort Gyre. This 

negative salinity anomaly (reservoir of fresh water) drives the ocean’s thermohaline circulation 

anticyclonically and stabilizes the upper ocean circulation. We formulate a hypothesis explaining 

the existence and variability of the salinity anomaly in the Beaufort Gyre and its transport to the 

North Atlantic. This hypothesis is based on the assumption that the Arctic Ocean can accumulate 

a significant amount of fresh water during an anticyclonic wind-driven circulation regime and then 

can release it to the North Atlantic during another climate state when the cyclonic circulation 

regime dominates. The accumulation and release of fresh water and ice in the Beaufort Gyre 

plays a fundamental role in the interaction between the Arctic Basin and the Greenland–Iceland–

Norwegian (GIN) Sea. The accumulation and subsequent release of the stored fresh water are 

regulated by wind-driven and thermohaline forcing. 

SIGNIFICANT CONCLUSIONS: 

– In ACCR years both winter and summer ice drift is anticyclonic, whereas in CCR years summer 

ice drift is cyclonic. This is crucial for the distribution of summer leads and other openings in the 

ice cover. Both observations and modeling results demonstrate that about 50% of the summer 

ice-free area in the Arctic is due to leads in the pack ice; the rest is due to ice melt in the marginal 

ice zone. Satellite images and numerical experiments show numerous openings in the ice cover, 

reaching in CCR, up to 40–45% of the total area in the center of the cyclonic rotation to the north 

of the Laptev Sea. 

– Both winds and water density gradients maintain summer anticyclonic surface oceanic 

circulation during ACCR; in CCR these two factors act in opposition, resulting in weaker summer 

surface currents and ice drift than in summer of the ACCR year, even though winds are stronger 

in CCR than in ACCR. 

– The different sea ice distributions due to ACCR or CCR atmospheric forcing are essential to 

the continued development of ice and ocean responses that are observed over the longer term. 

Differences due to the seasonal cycle in ACCR and CCR years seem to accumulate, leading to 

significant interannual variations. For example, summer openings in the pack ice due to cyclonic 

winds during the CCR are replaced with first-year ice by the end of the following winter. 

Repetition of this process over several years of CCR leads to thinner ice in the central Arctic. 

– The simulations suggest that ice and freshwater export from the Arctic Ocean may be an 

effective regulator of stratification in the Greenland Sea. Our numerical experiments show that a 

CCR year is associated with significant freshening in the Greenland Sea and adjacent areas. The 

establishment of strong stratification in the GIN seas due to excess freshwater supply from the 

Arctic follows a cyclic pattern with periods coinciding with the change of the Arctic Ocean 
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circulation regimes. 

– The analysis of remotely-sensed fields indicates that anticyclonic and cyclonic modes differ 

substantially in their effects on total ice concentration, multi-year ice concentration, ice motion, 

deformation, and ice extent. These results have a variety of implications for regional and longterm ice prediction, assessment of the sea ice record as an indicator of climatic change, and 

estimation of the role of sea ice on climate variability under different atmospheric circulation 

regimes. 

– Interannual variations in the Beaufort Sea ice cover play a crucial role in climatic and 

socioeconomic conditions along the Alaskan North Slope. Utilizing atmospheric and sea ice data, 

a new long-range ice forecasting scheme was developed by Drobot and Maslanik in 2002. 

Continued analysis into the physical links between oceanic and atmospheric conditions could also 

lend greater confidence to the presented results, and the inclusion of more sample years should 

improve confidence in the this model. 

STUDY RESULTS: 

– The hypothesis concerning different seasonal variability of the major atmospheric, sea ice, and 

oceanic parameters in the cyclonic and anticyclonic arctic climate states is confirmed; 

– Seasonal variability of the atmospheric, sea ice, and oceanic parameters is described and 

presented in the report in figures and in the digital form on CD-ROM and is posted at the WHOI 

arctic group web site: http://www.whoi.edu/science/PO/arcticgroup/projects.html 

– The project presents a new hypothesis along with supporting evidence that the Beaufort Gyre 

plays a significant role in regulating Arctic climate variability. We propose and demonstrate that 

the Beaufort Gyre accumulates a significant amount of fresh water during one climate regime 

(anticyclonic) and releases this water to the North Atlantic during another climate regime 

(cyclonic). This hypothesis can explain the origin of the salinity anomaly periodically found in the 

North Atlantic as well as its role in the decadal variability in the Arctic region and also can explain 

a feedback of this mechanisms on the climatic conditions in the Beaufort and Chukchi seas. 

STUDY PRODUCTS: 

Publications 

Drobot, S.D. and J.A. Maslanik. 2002. A practical method for long-range forecasting in the 

Beaufort Sea. Geophys. Res. Lett. 29:10.1029/2001GL014173. 

Drobot, S.D., and J.A. Maslanik. Interannual variability in summer Beaufort Sea ice conditions: 

Relationship to spring and summer surface and atmospheric variability. J. Geophys. Res. (in 

review) 

Polyakov, I.V., A.Y. Proshutinsky and M. Johnson. 1999. Seasonal cycles in two regimes of 

Arctic climate. J. Geophys. Res. 104:25761–25788. 

Proshutinsky A. 2001. Arctic climate variability in the 20th century, p. 125–128. In Extended 

abstracts of the Second Wadati Conference, 7–9 March 2001, Tsukuba, Japan. 

Proshutinsky, A. 2001. Arctic climate variability in the 20th Century, p. 28–29. In Woods Hole 

Oceanographic Institution 2001 Annual Report. 

Proshutinsky, A. 2002. Investigation of sea level change in the Arctic Ocean, p. 52–53. In V. 

Rachold, J. Brown, and S. Solomon [eds.], Arctic Coastal Dynamics, Report of an International 

Workshop, Potsdam (Germany) 26–30 November 2001. Alfred Wegener Institute for Polar and 

Marine Research. 

Proshutinsky, A.Y., and R.H. Bourke. The role of the Beaufort Gyre in Arctic climate variability: 

Seasonal to decadal climate scales, Geophys. Res. Lett. (resubmitted) 

Proshutinsky, A.Y., R.H. Bourke and F.A. McLaughlin. 2002. The role of the Beaufort Gyre in 

Arctic climate variability: Seasonal to decadal climate scales. Geophys. Res. Lett. 29(23), 1110, 

doi:10.1029/2002GL015847. 

Proshutinsky, A.Y., and M. Johnson. 2001. Two regimes of the Arctic’s circulation from ocean 

models with ice and contaminants. Mar. Pollut. Bull. 43:61–70. 

Proshutinsky, A.Y., M.A. Johnson, J.A. Maslanik and T.O. Proshutinsky. 2000. Beaufort and 

Chukchi Sea seasonal variability for two arctic climate states, p. 59–68. In University of Alaska 
Coastal Marine Institute Annual Report No. 7. OCS Study MMS 2000-070, University of Alaska 

Fairbanks and USDOI, MMS, Alaska OCS Region. 

Proshutinsky, A.Y., J.A. Maslanik, M.A. Johnson and T.O. Proshutinsky. 2002. Beaufort and 

Chukchi Sea seasonal variability for two arctic climate states, p. 52–64. In University of Alaska 

Coastal Marine Institute Annual Report No. 8. OCS Study MMS 2002-001, University of Alaska 

Fairbanks and USDOI, MMS, Alaska OCS Region. 

Proshutinsky, A., M. Johnson and T. Proshutinsky. 2001. Understanding climatic controls on 

sea-ice transport pathways in the Arctic Ocean. Ann. Glaciol. 33:551–554. 

Proshutinsky, A.Y., M.A. Johnson, T.O. Proshutinsky and J.A. Maslanik. 2003. Beaufort and 

Chukchi Sea seasonal variability for two arctic climate states. Final Report. OCS Study MMS 

2003-024, University of Alaska Coastal Marine Institute, University of Alaska Fairbanks and 

USDOI, MMS, Alaska OCS Region, 197 p. 

Proshutinsky, A.Y., J.A. Maslanik, T.O. Proshutinsky and M.A. Johnson. Seasonal variability of 

the Beaufort and Chukchi Sea for two arctic climate states. (in preparation) 

Proshutinsky, A.Y., J.A. Maslanik and S. Solomon. Arctic storms in the Beaufort and Chukchi 

Seas from observations and model results. (in preparation) 

Proshutinsky, A., V. Pavlov and R.H. Bourke. 2001. Sea level rise in the Arctic Ocean, Geophys. 

Res. Lett. 28:2237–2240. 

Proshutinsky A.Y., I.V. Polyakov and M.A. Johnson. 1999. Climate states and variability of Arctic 

ice and water dynamics during 1946–1997, Polar Res. 18:135–142. 

Proshutinsky, A., and T. Proshutinsky. 1999. Arctic atmosphere and ocean oscillations. Arctic 

Oscillation Section A42C-01, Supplement to EOS, Transactions, AGU 80:F212. 

Presentations (A.Y. Proshutinsky except where noted) 

Seasonal Variability of the Beaufort and Chukchi Seas in two arctic climate states. University of 

Alaska Coastal Marine Institute Annual Research Review, 9 March 2000, Fairbanks, Alaska. 

Beaufort and Chukchi Seas seasonal variability for two arctic climate states. MMS seminar 

presentation, 1 June 2000, Anchorage. 

Arctic climate variability during 20th century. WOCE/CLIVAR Representativeness and Variability 

Workshop, 17–20 October 2000, Fukuoka, Japan. 

Arctic atmosphere and ocean oscillations. NOAA/IPRC/CLIVAR Decadal Climate Variability 

Meeting, 8–12 January 2001, Honolulu. 

Seasonal Variability of the Beaufort and Chukchi Seas in two arctic climate states. MMS, 

February 2001, Anchorage. 

Seasonal Variability of the Beaufort and Chukchi Seas in two arctic climate states. University of 

Alaska Coastal Marine Institute Annual Research Review, 23 February 2001, Fairbanks. 

Arctic climate variability during 20th century. The Second Wadati Conference on Global Change 

and the Polar Climate, 7–9 March 2001, Tsukuba, Japan. (organizer and chairman) 

The Bering and Barents Seas data bases. Trajectories of Marine Ecosystem Workshop, 7–9 April 

2001. Fairbanks. 

Arctic storms. Eighth MMS Information Transfer Meeting, 3–5 April 2001, Anchorage Alaska. 

Beaufort and Chukchi Sea seasonal variability for two arctic climate states. Eighth MMS 

Information Transfer Meeting, 3–5 April 2001, Anchorage. 

Investigation of the Beaufort Sea Seasonal Variability. NOAA Arctic Exploratory Expedition 

Planning Workshop, 25–26 July 2001, Washington, D.C. 

A.Y. Proshutinsky, R.H. Bourke and T. Proshutinsky. Variability of freshwater storage and 

thermohaline circulation of the Arctic Ocean. IAPSO Meeting, October 2001, Mar Del Plata, 

Argentina. 

Beaufort Gyre as a flywheel of the Arctic Ocean Circulation: Seasonal, interannual and decadal 

time scales. 22 March 2002, McGill University. 

Once again: Two circulation regimes of the Arctic Ocean circulation. Beaufort Gyre case study. 

Workshop on Measurement/Modelling of the Arctic Ocean Circulation, 17–20 June 2002, 

Lamont-Doherty Observatory. 

Sea ice assimilation in the storm surge models: A case study for the Arctic seas. NASA Sea Ice 

Data Assimilation Workshop, 23–24 July 2002, Annapolis, Maryland. 

*P.I.’s affiliation may be different than that listed for Project Manager(s). 
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Arctic subregion base map. 

0 E

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Beaufort and Chukchi Sea region (cross-hatched sector) where 

sea ice extent and sea ice area were calculated.