Anticyclonic Eddies in the Alaskan Stream

Hiromichi Ueno Institute of Observational Research for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan

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Kanako Sato Institute of Observational Research for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan

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Howard J. Freeland Institute of Ocean Sciences, Fisheries and Oceans Canada, Sidney, British Columbia, Canada

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William R. Crawford Institute of Ocean Sciences, Fisheries and Oceans Canada, Sidney, British Columbia, Canada

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Hiroji Onishi Division of Marine Bioresource and Environmental Science, Graduate School of Fisheries Science, Hokkaido University, Hakodate, Japan

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Eitarou Oka Institute of Observational Research for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan
Ocean Research Institute, University of Tokyo, Tokyo, Japan

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Toshio Suga Institute of Observational Research for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan
Department of Geophysics, Graduate School of Science, Tohoku University, Sendai, Japan

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Abstract

Anticyclonic eddies propagating southwestward in the Alaskan Stream (AS) were investigated through analysis of altimetry data from satellite observations during 1992–2006 and hydrographic data from profiling float observations during 2001–06. Fifteen long-lived eddies were identified and categorized based on their area of first appearance. Three eddies were present at the beginning of the satellite observations; another three formed in the eastern Gulf of Alaska off Sitka, Alaska; and four were first detected at the head of the Gulf of Alaska near Yakutat, Alaska. The other five eddies formed along the AS between 157° and 169°W, and were named AS eddies. While the eddies that formed in the Gulf of Alaska mainly decayed before exiting the Gulf of Alaska, the AS eddies mostly crossed the 180° meridian and reached the western subarctic gyre. Four of five AS eddies formed under negative or weakly positive wind stress curls, which possibly caused AS separation from the coast. Comparison of eddy propagation speeds in the AS with the bottom slope showed that eddies propagated faster over steeper slopes, although eddy speeds were slower than those predicted by the topographic planetary wave dispersion relation. An AS eddy was observed by profiling floats in the western subarctic gyre after it detached from the AS. Intermediate-layer water near the eddy center had low potential vorticity compared with the surrounding water, suggesting that AS eddies provided the western subarctic gyre with water just south of the Aleutian Islands.

Corresponding author address: Hiromichi Ueno, Institute of Observational Research for Global Change, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan. Email: uenohiro@jamstec.go.jp

Abstract

Anticyclonic eddies propagating southwestward in the Alaskan Stream (AS) were investigated through analysis of altimetry data from satellite observations during 1992–2006 and hydrographic data from profiling float observations during 2001–06. Fifteen long-lived eddies were identified and categorized based on their area of first appearance. Three eddies were present at the beginning of the satellite observations; another three formed in the eastern Gulf of Alaska off Sitka, Alaska; and four were first detected at the head of the Gulf of Alaska near Yakutat, Alaska. The other five eddies formed along the AS between 157° and 169°W, and were named AS eddies. While the eddies that formed in the Gulf of Alaska mainly decayed before exiting the Gulf of Alaska, the AS eddies mostly crossed the 180° meridian and reached the western subarctic gyre. Four of five AS eddies formed under negative or weakly positive wind stress curls, which possibly caused AS separation from the coast. Comparison of eddy propagation speeds in the AS with the bottom slope showed that eddies propagated faster over steeper slopes, although eddy speeds were slower than those predicted by the topographic planetary wave dispersion relation. An AS eddy was observed by profiling floats in the western subarctic gyre after it detached from the AS. Intermediate-layer water near the eddy center had low potential vorticity compared with the surrounding water, suggesting that AS eddies provided the western subarctic gyre with water just south of the Aleutian Islands.

Corresponding author address: Hiromichi Ueno, Institute of Observational Research for Global Change, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan. Email: uenohiro@jamstec.go.jp

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  • Antonov, J. I., R. A. Locarnini, T. P. Boyer, A. V. Mishonov, and H. E. Garcia, 2006: Salinity. Vol. 2, World Ocean Atlas 2005, NOAA Atlas NESDIS 62, 182 pp.

    • Search Google Scholar
    • Export Citation
  • Argo Science Team, 2001: The global array of profiling floats. Observing the Oceans in the 21st Century, C. J. Koblinsky and N. R. Smith, Eds., GODAE Project Office, Bureau of Meteorology, 248–258.

  • AVISO, 2007: SSALTO/DUACS user handbook: (M)SLA and (M)ADT near-real time and delayed time products. Version 1, Revision 8, CLS, Ramonville St-Agne, France, 42 pp. [Available from CLS, 8-10 Rue Hermès, Parc Technologique du Canal, 31526 Ramonville St-Agne, France.].

  • Boyd, P. W., C. S. Wong, J. Merrill, F. Whitney, J. Snow, P. J. Harrison, and J. Gower, 1998: Atmospheric iron supply and enhanced vertical carbon flux in the NE subarctic Pacific: Is there a connection? Global Biogeochem. Cycles, 12 , 429441.

    • Search Google Scholar
    • Export Citation
  • Boyd, P. W., and Coauthors, 2004: The decline and fate of an iron-induced subarctic phytoplankton bloom. Nature, 428 , 549553.

  • Chelton, D. B., R. A. de Szoeke, M. G. Schlax, K. E. Naggar, and N. Siwertz, 1998: Geographical variability of first baroclinic Rossby radius of deformation. J. Phys. Oceanogr., 28 , 433460.

    • Search Google Scholar
    • Export Citation
  • Chelton, D. B., M. G. Schlax, R. M. Samelson, and R. A. de Szoeke, 2007: Global observations of large oceanic eddies. Geophys. Res. Lett., 34 , L15606. doi:10.1029/2007GL030812.

    • Search Google Scholar
    • Export Citation
  • Crawford, W. R., 2002: Physical characteristics of Haida eddies. J. Oceanogr., 58 , 703713.

  • Crawford, W. R., 2005: Heat and fresh water transport by eddies into the Gulf of Alaska. Deep-Sea Res. II, 52 , 893908.

  • Crawford, W. R., and F. Whitney, 1999: Mesoscale eddies aswirl with data in Gulf of Alaska ocean. Eos, Trans. Amer. Geophys. Union, 80 , 365370.

    • Search Google Scholar
    • Export Citation
  • Crawford, W. R., J. Y. Cherniawsky, and M. G. G. Foreman, 2000: Multi-year meanders and eddies in the Alaskan Stream as observed by TOPEX/Poseidon altimeter. Geophys. Res. Lett., 27 , 10251028.

    • Search Google Scholar
    • Export Citation
  • Crawford, W. R., P. J. Brickley, T. D. Peterson, and A. C. Thomas, 2005: Impact of Haida eddies on chlorophyll distribution in the eastern Gulf of Alaska. Deep-Sea Res. II, 52 , 975989.

    • Search Google Scholar
    • Export Citation
  • Crawford, W. R., P. J. Brickley, and A. C. Thomas, 2007: Mesoscale eddies dominate surface phytoplankton in northern Gulf of Alaska. Prog. Oceanogr., 75 , 287303.

    • Search Google Scholar
    • Export Citation
  • Di Lorenzo, E., M. G. G. Foreman, and W. R. Crawford, 2005: Modelling the generation of Haida eddies. Deep-Sea Res. II, 52 , 853873.

  • Ducet, N., P. Y. Le Traon, and G. Reverdin, 2000: Global high-resolution mapping of ocean circulation from TOPEX/Poseidon and ERS-1 and -2. J. Geophys. Res., 105 , (C8). 1947719498.

    • Search Google Scholar
    • Export Citation
  • Emery, W. J., W. G. Lee, and L. Magaard, 1984: Geographic and seasonal distribution of Brunt–Väisälä frequency and Rossby radii in the North Pacific and North Atlantic. J. Phys. Oceanogr., 14 , 294317.

    • Search Google Scholar
    • Export Citation
  • Favorite, F., 1974: Flow into the Bering Sea through Aleutian island passes. Oceanography of the Bering Sea with Emphasis on Renewable Resources, D. W. Hood and E. J. Kelley, Eds., Institute of Marine Science, University of Alaska—Fairbanks, 3–37.

    • Search Google Scholar
    • Export Citation
  • Freeland, H. J., P. B. Rhines, and T. Rossby, 1975: Statistical observations of the trajectories of neutrally buoyant floats in the North Atlantic. J. Mar. Res., 33 , 383404.

    • Search Google Scholar
    • Export Citation
  • Gower, J. F. R., 1989: Geosat altimeter observations of the distribution and movement of sea-surface height anomalies in the north-east Pacific. Proc. Oceans 89: The Global Ocean, Seattle, WA, IEEE, 977–981.

  • Harrison, P. J., P. W. Boyd, D. E. Varela, S. Takeda, A. Shiomoto, and T. Odate, 1999: Comparison of factors controlling phytoplankton productivity in the NE and NW subarctic Pacific gyres. Prog. Oceanogr., 43 , 205234.

    • Search Google Scholar
    • Export Citation
  • Henson, S. A., and A. C. Thomas, 2008: A census of oceanic anticyclonic eddies in the Gulf of Alaska. Deep-Sea Res. I, 55 , 163176.

  • Johnson, W. K., L. A. Miller, N. E. Sutherland, and C. S. Wong, 2005: Iron transport by mesoscale Haida eddies in the Gulf of Alaska. Deep-Sea Res. II, 52 , 933953.

    • Search Google Scholar
    • Export Citation
  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77 , 437471.

  • Killworth, P. D., D. B. Chelton, and R. A. de Szoeke, 1997: The speed of observed and theoretical long extratropical planetary waves. J. Phys. Oceanogr., 27 , 19461966.

    • Search Google Scholar
    • Export Citation
  • Kubokawa, A., 1991: On the behavior of outflows with low potential vorticity from a sea strait. Tellus, 43A , 168176.

  • Ladd, C., 2007: Interannual variability of the Gulf of Alaska eddy field. Geophys. Res. Lett., 34 , L11605. doi:10.1029/2007GL029478.

  • Ladd, C., G. L. Hunt Jr., C. W. Mordy, S. A. Salo, and P. J. Stabeno, 2005a: Marine environment of the eastern and central Aleutian Islands. Fish. Oceanogr., 14 , (S1). 2238.

    • Search Google Scholar
    • Export Citation
  • Ladd, C., N. B. Kachel, C. W. Mordy, and P. J. Stabeno, 2005b: Observations from a Yakutat eddy in the northern Gulf of Alaska. J. Geophys. Res., 110 , C03003. doi:10.1029/2004JC002710.

    • Search Google Scholar
    • Export Citation
  • Ladd, C., P. J. Stabeno, and E. D. Cokelet, 2005c: A note on cross-shelf exchange in the northern Gulf of Alaska. Deep-Sea Res. I, 52 , 667679.

    • Search Google Scholar
    • Export Citation
  • Ladd, C., C. W. Mordy, N. B. Kachel, and P. J. Stabeno, 2007: Northern Gulf of Alaska eddies and associated anomalies. Deep-Sea Res. I, 54 , 487509.

    • Search Google Scholar
    • Export Citation
  • LeBlond, P. H., and L. A. Mysak, 1978: Waves in the Ocean. Elsevier, 602 pp.

  • Le Traon, P. Y., Y. Faugere, F. Hernandez, J. Dorandeu, F. Mertz, and M. Ablain, 2003: Can we merge GEOSAT follow-on with TOPEX/Poseidon and ERS-2 for an improved description of the ocean circulation? J. Atmos. Oceanic Technol., 20 , 889895.

    • Search Google Scholar
    • Export Citation
  • Locarnini, R. A., A. V. Mishonov, J. I. Antonov, T. P. Boyer, and H. E. Garcia, 2006: Temperature. Vol. 1, World Ocean Atlas 2005, NOAA Atlas NESDIS 61, 182 pp.

    • Search Google Scholar
    • Export Citation
  • Macdonald, A. M., T. Suga, and R. G. Curry, 2001: An isopycnally averaged North Pacific climatology. J. Atmos. Oceanic Technol., 18 , 394420.

    • Search Google Scholar
    • Export Citation
  • Mackas, D. L., and M. Galbraith, 2002: Zooplankton community composition along the inner portion of Line P during the 1997–1998 El Niño event. Prog. Oceanogr., 54 , 423437.

    • Search Google Scholar
    • Export Citation
  • Martin, J. H., R. M. Gordon, S. Fitzwater, and W. W. Brokenow, 1989: Vertex: Phytoplankton/iron studies in the Gulf of Alaska. Deep-Sea Res., 30 , 649680.

    • Search Google Scholar
    • Export Citation
  • Musgrave, D. L., T. J. Weingartner, and T. C. Royer, 1992: Circulation and hydrography in the northwestern Gulf of Alaska. Deep-Sea Res., 39A , 14991519.

    • Search Google Scholar
    • Export Citation
  • National Geophysical Data Center, cited. 2006: 2-minute gridded global relief data (ETOPO2v2). [Available online at http://www.ngdc.noaa.gov/mgg/fliers/06mgg01.html.].

    • Search Google Scholar
    • Export Citation
  • Oka, E., L. D. Talley, and T. Suga, 2007: Temporal variability of winter mixed layer in the mid- to high-latitude North Pacific. J. Oceanogr., 63 , 293307.

    • Search Google Scholar
    • Export Citation
  • Okkonen, S. R., 1992: The shedding of an anticyclonic eddy from the Alaskan Stream as observed by the Geosat altimeter. Geophys. Res. Lett., 19 , 23972400.

    • Search Google Scholar
    • Export Citation
  • Okkonen, S. R., 1993: Observations of topographic planetary waves in the Bering Slope Current using the Geosat altimeter. J. Geophys. Res., 98 , (C12). 2260322613.

    • Search Google Scholar
    • Export Citation
  • Okkonen, S. R., 1996: The influence of an Alaskan Stream eddy on flow through Amchitka Pass. J. Geophys. Res., 101 , (C4). 88398851.

  • Okkonen, S. R., G. A. Jacobs, E. J. Metzger, H. E. Hurlburt, and J. F. Shriver, 2001: Mesoscale variability in the boundary currents of the Alaska Gyre. Cont. Shelf Res., 21 , 12191236.

    • Search Google Scholar
    • Export Citation
  • Okkonen, S. R., T. J. Weingartner, S. L. Danielson, D. L. Musgrave, and G. M. Schmidt, 2003: Satellite and hydrographic observations of eddy-induced shelf-slope exchange in the northwestern Gulf of Alaska. J. Geophys. Res., 108 , 3033. doi:10.1029/2002JC001342.

    • Search Google Scholar
    • Export Citation
  • Onishi, H., 2001: Spatial and temporal variability in a vertical section across the Alaskan Stream and subarctic current. J. Oceanogr., 57 , 7991.

    • Search Google Scholar
    • Export Citation
  • Onishi, H., and K. Ohtani, 1999: On seasonal and year-to-year variation in flow of the Alaskan Stream in the central North Pacific. J. Oceanogr., 55 , 597608.

    • Search Google Scholar
    • Export Citation
  • Pascual, A., Y. Faugere, G. Larnicol, and P. Y. Le Traon, 2006: Improved description of the ocean mesoscale variability by combining four satellite altimeters. Geophys. Res. Lett., 33 , L02611. doi:10.1029/2005GL024633.

    • Search Google Scholar
    • Export Citation
  • Reed, R. K., and J. D. Schumacher, 1986: Physical oceanography. The Gulf of Alaska: Physical Environment and Biological Resourses, D. W. Hood and S. T. Zimmerman, Eds., NOAA, 57–75.

    • Search Google Scholar
    • Export Citation
  • Reed, R. K., and P. J. Stabeno, 1997: Long-term measurements of flow near Aleutian Islands. J. Mar. Res., 55 , 565575.

  • Reed, R. K., J. D. Schumacher, and L. S. Incze, 1986: Water properties and circulation in Shelikof Strait, Alaska during 1985. NOAA Tech. Memo. ERL PMEL-68, 35 pp. [NTIS PB87-143053.].

    • Search Google Scholar
    • Export Citation
  • Reed, R. K., J. D. Schumacher, and L. S. Incze, 1987: Circulation in Shelikof Strait, Alaska. J. Phys. Oceanogr., 17 , 15461554.

  • Rogachev, K., N. Shlyk, and E. Carmack, 2007: The shedding of mesoscale anticyclonic eddies from the Alaskan Stream and westward transport of warm water. Deep-Sea Res. II, 54 , 26432656.

    • Search Google Scholar
    • Export Citation
  • Stabeno, P. J., and A. J. Hermann, 1996: An eddy circulation model for the western Gulf of Alaska shelf. 2. Comparison of results to oceanographic observations. J. Geophys. Res., 101 , (C1). 11511161.

    • Search Google Scholar
    • Export Citation
  • Stabeno, P. J., N. A. Bond, A. J. Hermann, N. B. Kachel, C. W. Mordy, and J. E. Overland, 2004: Meteorology and oceanography of the northern Gulf of Alaska. Cont. Shelf Res., 24 , 859897.

    • Search Google Scholar
    • Export Citation
  • Strub, P. T., and C. James, 2002: Altimeter-derived surface circulation in the large-scale NE Pacific gyres: Part 1. Seasonal variability. Prog. Oceanogr., 53 , 163183.

    • Search Google Scholar
    • Export Citation
  • Suga, T., K. Motoki, Y. Aoki, and A. M. Macdonald, 2004: The North Pacific climatology of winter mixed layer and mode waters. J. Phys. Oceanogr., 34 , 322.

    • Search Google Scholar
    • Export Citation
  • Tabata, S., 1982: The anticyclonic, baroclinic eddy off Sitka, Alaska, in the northeast Pacific Ocean. J. Phys. Oceanogr., 12 , 12601282.

    • Search Google Scholar
    • Export Citation
  • Thomson, R. E., 1972: On the Alaskan Stream. J. Phys. Oceanogr., 2 , 363371.

  • Ueno, H., and I. Yasuda, 2003: Intermediate water circulation in the North Pacific subarctic and northern subtropical regions. J. Geophys. Res., 108 , 3348. doi:10.1029/2002JC001372.

    • Search Google Scholar
    • Export Citation
  • Ueno, H., E. Oka, T. Suga, and H. Onishi, 2005: Seasonal and interannual variability of temperature inversions in the subarctic North Pacific. Geophys. Res. Lett., 32 , L20603. doi:10.1029/2005GL023948.

    • Search Google Scholar
    • Export Citation
  • Ueno, H., E. Oka, T. Suga, H. Onishi, and D. Roemmich, 2007: Formation and variation of temperature inversions in the eastern subarctic North Pacific. Geophys. Res. Lett., 34 , L05603. doi:10.1029/2006GL028715.

    • Search Google Scholar
    • Export Citation
  • Whitney, F., and M. Robert, 2002: Structure of Haida eddies and their transport of nutrient from coastal margins into the NE Pacific Ocean. J. Oceanogr., 58 , 715723.

    • Search Google Scholar
    • Export Citation
  • Wong, C. S., N. A. D. Waser, Y. Nojiri, F. A. Whitney, J. S. Page, and J. Zeng, 2002: Seasonal cycles of nutrients and dissolved inorganic carbon at high and mid latitudes in the North Pacific Ocean during the Skaugran cruises: Determination of new production and nutrient uptake ratios. Deep-Sea Res. II, 49 , 53175338.

    • Search Google Scholar
    • Export Citation
  • Yasuda, I., and Coauthors, 2000: Cold-core anticyclonic eddies south of the Bussol’ Strait in the northwestern subarctic Pacific. J. Phys. Oceanogr., 30 , 11371157.

    • Search Google Scholar
    • Export Citation
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