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| Stopa, J. E.; Ardhuin, Fabrice; Thomson, Jim; Smith, Madison M.; Kohout, Alison; Doble, Martin; Wadhams, Peter. |
| A storm with significant wave heights exceeding 4 m occurred in the Beaufort Sea on 11 to 13 October, 2015. The waves and ice were captured on 12 October by the Synthetic Aperture Radar (SAR) on board Sentinel‐1A, with Interferometric Wide swath images covering 400 × 1100 km at 10 m resolution. This dataset allows the estimation of wave spectra across the marginal ice zone (MIZ) every 5 km, over 400 km of sea ice. Since ice attenuates waves with wavelengths shorter than 50 m in a few kilometers, the longer waves are clearly imaged by SAR in sea ice. Obtaining wave spectra from the image requires a careful estimation of the blurring effect produced by unresolved wavelengths in the azimuthal direction. Using in‐situ wave buoy measurements as reference, we... |
| Tipo: Text |
Palavras-chave: Wave-ice interaction; Arctic Ocean marginal ice zone; Sentinel-1A SAR; Arctic Sea State Boundary Layer Physics Program; Remote sensing; Wave attenuation. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00439/55084/56519.pdf |
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| Ardhuin, Fabrice; Stopa, Justin; Chapron, Bertrand; Collard, Fabrice; Smith, Madison; Thomson, Jim; Doble, Martin; Blomquist, Byron; Persson, Ola; Collins, Clarence O., Iii; Wadhams, Peter. |
| Measurements of wave heights in marginal ice zones are limited to very few in situ data. Here we revisit the linear and quasilinear theories of Synthetic Aperture Radar imaging of waves in the particular case of waves in sea ice. Instead of only working with spectra, we have developed an iterative nonlinear algorithm to estimate phase-resolved deterministic maps of wave-induced orbital velocities, from which elevation spectra can be derived. Application of this algorithm to Sentinel 1A wave mode images in the Southern Ocean shows that it produces reasonable results for swells in all directions except when they propagate at a few degrees off the range direction. The estimate of wave parameters is expected to work best when the shortest wave components,... |
| Tipo: Text |
Palavras-chave: SAR; Sentinel-1A; Ocean waves; Sea ice. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00361/47214/47451.pdf |
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| Thomson, Jim; Fan, Yalin; Stammerjohn, Sharon; Stopa, Justin; Erick Rogers, W.; Girard-ardhuin, Fanny; Ardhuin, Fabrice; Shen, Hayley; Perrie, Will; Shen, Hui; Ackley, Steve; Babanin, Alex; Liu, Qingxiang; Guest, Peter; Maksym, Ted; Wadhams, Peter; Fairall, Chris; Persson, Ola; Doble, Martin; Graber, Hans; Lund, Bjoern; Squire, Vernon; Gemmrich, Johannes; Lehner, Susanne; Holt, Benjamin; Meylan, Mike; 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.... |
| Tipo: Text |
Palavras-chave: Sea ice; Arctic Ocean; Ocean surface waves. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00345/45590/45202.pdf |
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| Thomson, Jim; Ackley, Stephen; Girard-ardhuin, Fanny; Ardhuin, Fabrice; Babanin, Alex; Boutin, Guillaume; Brozena, John; Cheng, Sukun; Collins, Clarence; Doble, Martin; Fairall, Chris; Guest, Peter; Gebhardt, Claus; Gemmrich, Johannes; Graber, Hans C.; Holt, Benjamin; Lehner, Susanne; Lund, Bjorn; Meylan, Michael H.; Maksym, Ted; Montiel, Fabien; Perrie, Will; Persson, Ola; Rainville, Luc; Rogers, W. Erick; Shen, Hui; Shen, Hayley; Squire, Vernon; Stammerjohn, Sharon; 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... |
| Tipo: Text |
Palavras-chave: Arctic; Waves; Autumn; Sea ice; Beaufort; Flux. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00437/54837/56313.pdf |
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| Itkin, Polona; Spreen, Gunnar; Cheng, Bin; Doble, Martin; Girard-ardhuin, Fanny; Haapala, Jari; Hughes, Nick; Kaleschke, Lars; Nicolaus, Marcel; Wilkinson, Jeremy. |
| Arctic sea ice has displayed significant thinning as well as an increase in drift speed in recent years. Taken together this suggests an associated rise in sea ice deformation rate. A winter and spring expedition to the sea ice covered region north of Svalbard–the Norwegian young sea ICE2015 expedition (N-ICE2015)—gave an opportunity to deploy extensive buoy arrays and to monitor the deformation of the first-year and second-year ice now common in the majority of the Arctic Basin. During the 5 month long expedition, the ice cover underwent several strong deformation events, including a powerful storm in early February that damaged the ice cover irreversibly. The values of total deformation measured during N-ICE2015 exceed previously measured values in the... |
| Tipo: Text |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00392/50365/51067.pdf |
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| Ardhuin, Fabrice; Sutherland, Peter; Doble, Martin; Wadhams, Peter. |
| The poorly understood attenuation of surface waves in sea ice is generally attributed to the combination of scattering and dissipation. Scattering and dissipation have very different effects on the directional and temporal distribution of wave energy, making it possible to better understand their relative importance by analysis of swell directional spreading and arrival times. Here we compare results of a spectral wave model – using adjustable scattering and dissipation attenuation formulations – with wave measurements far inside the ice pack. In this case, scattering plays a negligible role in the attenuation of long swells. Specifically, scattering-dominated attenuation would produce directional wave spectra much broader than the ones recorded, and swell... |
| Tipo: Text |
Palavras-chave: Ocean waves; Sea ice; Tara; DAMOCLES. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00333/44455/44127.pdf |
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| Ardhuin, Fabrice; Boutin, Guillaume; Stopa, Justin; Girard-ardhuin, Fanny; Melsheimer, Christian; Thomson, Jim; Kohout, Alison; Doble, Martin; Wadhams, Peter. |
| Many processes that affect ocean surface gravity waves in sea ice give rise to attenuation rates that vary with both wave frequency and amplitude. Here we particularly test the possible effects of basal friction, scattering by ice floes, and dissipation in the ice layer due to dislocations, and ice breakup by the waves. The possible influence of these processes is evaluated in the marginal ice zone of the Beaufort Sea, where extensive wave measurements were performed. The wave data includes in situ measurements and the first kilometer-scale map of wave heights provided by Sentinel-1 SAR imagery on 12 October 2015, up to 400 km into the ice. We find that viscous friction at the base of an ice layer gives a dissipation rate that may be too large near the ice... |
| Tipo: Text |
Palavras-chave: Wind-waves; Sea ice; WAVEWATCH III; SAR; Beaufort; Arctic. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00462/57372/59439.pdf |
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