Persson Ola

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Persson
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Ola
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  • Article
    Overview of the Arctic Sea state and boundary layer physics program
    (American Geophysical Union, 2018-04-16) Thomson, Jim ; Ackley, Stephen ; Girard-Ardhuin, Fanny ; Ardhuin, Fabrice ; Babanin, Alexander ; Boutin, Guillaume ; Brozena, John ; Cheng, Sukun ; Collins, Clarence ; Doble, Martin ; Fairall, Christopher W. ; Guest, Peter ; Gebhardt, Claus ; Gemmrich, Johannes ; Graber, Hans C. ; Holt, Benjamin ; Lehner, Susanne ; Lund, Björn ; Meylan, Michael ; Maksym, Ted ; Montiel, Fabien ; Perrie, Will ; Persson, Ola ; Rainville, Luc ; Rogers, W. Erick ; Shen, Hui ; Shen, Hayley ; Squire, Vernon ; Stammerjohn, Sharon E. ; Stopa, Justin ; Smith, Madison M. ; Sutherland, Peter ; Wadhams, Peter
    A large collaborative program has studied the coupled air‐ice‐ocean‐wave processes occurring in the Arctic during the autumn ice advance. The program included a field campaign in the western Arctic during the autumn of 2015, with in situ data collection and both aerial and satellite remote sensing. Many of the analyses have focused on using and improving forecast models. Summarizing and synthesizing the results from a series of separate papers, the overall view is of an Arctic shifting to a more seasonal system. The dramatic increase in open water extent and duration in the autumn means that large surface waves and significant surface heat fluxes are now common. When refreezing finally does occur, it is a highly variable process in space and time. Wind and wave events drive episodic advances and retreats of the ice edge, with associated variations in sea ice formation types (e.g., pancakes, nilas). This variability becomes imprinted on the winter ice cover, which in turn affects the melt season the following year.
  • Article
    Emerging trends in the sea state of the Beaufort and Chukchi seas
    (Elsevier, 2016-07-06) Thomson, James M. ; Fan, Yalin ; Stammerjohn, Sharon E. ; Stopa, Justin ; Rogers, W. Erick ; Girard-Ardhuin, Fanny ; Ardhuin, Fabrice ; Shen, Hayley ; Perrie, Will ; Shen, Hui ; Ackley, Stephen ; Babanin, Alexander ; Liu, Qingxiang ; Guest, Peter ; Maksym, Ted ; Wadhams, Peter ; Fairall, Christopher W. ; Persson, Ola ; Doble, Martin J. ; Graber, Hans C. ; Lund, Bjoern ; Squire, Vernon ; Gemmrich, Johannes ; Lehner, Susanne ; Holt, Benjamin ; Meylan, Michael ; Brozena, John ; Bidlot, Jean-Raymond
    The sea state of the Beaufort and Chukchi seas is controlled by the wind forcing and the amount of ice-free water available to generate surface waves. Clear trends in the annual duration of the open water season and in the extent of the seasonal sea ice minimum suggest that the sea state should be increasing, independent of changes in the wind forcing. Wave model hindcasts from four selected years spanning recent conditions are consistent with this expectation. In particular, larger waves are more common in years with less summer sea ice and/or a longer open water season, and peak wave periods are generally longer. The increase in wave energy may affect both the coastal zones and the remaining summer ice pack, as well as delay the autumn ice-edge advance. However, trends in the amount of wave energy impinging on the ice-edge are inconclusive, and the associated processes, especially in the autumn period of new ice formation, have yet to be well-described by in situ observations. There is an implicit trend and evidence for increasing wave energy along the coast of northern Alaska, and this coastal signal is corroborated by satellite altimeter estimates of wave energy.
  • Article
    Toward quantifying the increasing role oceanic heat in sea ice loss in the new Arctic
    (American Meteorological Society, 2015-12) Carmack, Eddy C. ; Polyakov, Igor V. ; Padman, Laurie ; Fer, Ilker ; Hunke, Elizabeth C. ; Hutchings, Jennifer K. ; Jackson, Jennifer M. ; Kelley, Daniel E. ; Kwok, Ron ; Layton, Chantelle ; Melling, Humfrey ; Perovich, Donald K. ; Persson, Ola ; Ruddick, Barry R. ; Timmermans, Mary-Louise ; Toole, John M. ; Ross, Tetjana ; Vavrus, Steve ; Winsor, Peter
    The loss of Arctic sea ice has emerged as a leading signal of global warming. This, together with acknowledged impacts on other components of the Earth system, has led to the term “the new Arctic.” Global coupled climate models predict that ice loss will continue through the twenty-first century, with implications for governance, economics, security, and global weather. A wide range in model projections reflects the complex, highly coupled interactions between the polar atmosphere, ocean, and cryosphere, including teleconnections to lower latitudes. This paper summarizes our present understanding of how heat reaches the ice base from the original sources—inflows of Atlantic and Pacific Water, river discharge, and summer sensible heat and shortwave radiative fluxes at the ocean/ice surface—and speculates on how such processes may change in the new Arctic. The complexity of the coupled Arctic system, and the logistic and technological challenges of working in the Arctic Ocean, require a coordinated interdisciplinary and international program that will not only improve understanding of this critical component of global climate but will also provide opportunities to develop human resources with the skills required to tackle related problems in complex climate systems. We propose a research strategy with components that include 1) improved mapping of the upper- and middepth Arctic Ocean, 2) enhanced quantification of important process, 3) expanded long-term monitoring at key heat-flux locations, and 4) development of numerical capabilities that focus on parameterization of heat-flux mechanisms and their interactions.