A5065955433- Arctic and Antarctic ice dynamics
- Oceanographic and Atmospheric Processes
- Icing and De-icing Technologies
- Methane Hydrates and Related Phenomena
- Ocean Waves and Remote Sensing
- Cryospheric studies and observations
- Climate change and permafrost
- Marine animal studies overview
- Geological Studies and Exploration
- Coastal and Marine Dynamics
- Scientific Research and Discoveries
- Marine and environmental studies
- Underwater Acoustics Research
- Climate variability and models
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Cephalopods and Marine Biology
- Environmental Monitoring and Data Management
- earthquake and tectonic studies
- Aerospace Engineering and Energy Systems
- Seismic Waves and Analysis
- Meteorological Phenomena and Simulations
- Tropical and Extratropical Cyclones Research
- Aquatic and Environmental Studies
Polar Scientific
2016-2022
University of Washington Applied Physics Laboratory
2022
Laboratoire d’Océanographie de Villefranche
2013-2015
Sorbonne Université
2011-2015
Université Paris Cité
2011
University of Cambridge
2003-2010
Centre National de la Recherche Scientifique
2009
Scottish Association For Marine Science
2003-2006
Scientific Committee on Antarctic Research
2003
Abstract Analysis of field measurements ocean surface wave activity in the marginal ice zone, from campaigns Arctic and Antarctic over a range different conditions, shows attenuation rate with respect to distance has power law dependence on frequency order between two four. With this backdrop, attenuation‐frequency dependencies given by three dispersion relation models are obtained under assumptions weak attenuation, negligible deviation number open water number, thin ice. It is found that...
Abstract A large collaborative program has studied the coupled air‐ice‐ocean‐wave processes occurring in Arctic during autumn ice advance. The included a field campaign western of 2015, with situ data collection and both aerial satellite remote sensing. Many analyses have focused on using improving forecast models. Summarizing synthesizing results from series separate papers, overall view is an shifting to more seasonal system. dramatic increase open water extent duration means that surface...
Abstract Arctic sea ice has displayed significant thinning as well an increase in drift speed recent years. Taken together this suggests associated rise deformation rate. A winter and spring expedition to the covered region north of Svalbard–the Norwegian young ICE2015 (N‐ICE2015)—gave opportunity deploy extensive buoy arrays monitor first‐year second‐year now common majority Basin. During 5 month long expedition, cover underwent several strong events, including a powerful storm early...
A model for wind-generated surface gravity waves, WAVEWATCH III®, is used to analyze and interpret buoy measurements of wave spectra. The applied a hindcast event in sea ice the western Arctic, 11–14 October 2015, which extensive ship-borne were made during research cruise. model, uses viscoelastic parameterization represent impact on found have good skill—after calibration effective viscosity—for prediction total energy, but over-predicts dissipation high frequency energy by ice. This...
The sea state of the Beaufort and Chukchi seas is controlled by wind forcing amount ice-free water available to generate surface waves. Clear trends in annual duration open season extent seasonal ice minimum suggest that should be increasing, independent changes forcing. Wave model hindcasts from four selected years spanning recent conditions are consistent with this expectation. In particular, larger waves more common less summer and/or a longer season, peak wave periods generally longer....
Abstract Wave attenuation coefficients ( α , m −1 ) were calculated from in situ data transmitted by custom wave buoys deployed into the advancing pancake ice region of Weddell Sea. Data cover a 12 day period as buoy array was first compressed and then dilated under influence passing low‐pressure system. Attenuation found to vary over more than 2 orders magnitude be far higher that observed broken‐floe marginal zones. A clear linear relation between thickness demonstrated, using novel...
Abstract This paper presents a wave‐in‐ice model calibration study. Data used were collected in the thin ice of advancing autumn marginal zone western Arctic Ocean 2015, where pancake was found to be prevalent. Multiple buoys deployed seven wave experiments; data from four these experiments are present Wave attenuation coefficients calculated utilizing energy decay between two measuring simultaneously within covered region. Wavenumbers measured one experiments. Forcing parameters obtained...
The Arctic is undergoing significant environmental changes due to climate warming. most evident signal of this warming the shrinking and thinning ice cover Ocean. If continues, as global models predict, Ocean will change from a perennially ice‐covered seasonally ice‐free ocean. Estimates when occur vary 2030s end century. One reason for huge uncertainty lack systematic observations describing state, variability, in
Abstract The poorly understood attenuation of surface waves in sea ice is generally attributed to the combination scattering and dissipation. Scattering dissipation have very different effects on directional temporal distribution wave energy, making it possible better understand their relative importance by analysis swell spreading arrival times. Here we compare results a spectral model—using adjustable formulations—with measurements far inside pack. In this case, plays negligible role long...
The generation and evolution of ocean waves by wind is one the most complex phenomena in geophysics, great practical significance. Predictive capabilities respective wave models, however, are impaired lack field situ observations, particularly extreme Metocean conditions. paper outlines highlights important gaps understanding processes suggests a major observational program Southern Ocean. This large, but poorly investigated part World Ocean home to weather around year. network would include...
Abstract This paper investigates the attenuation and directional spreading of large amplitude waves traveling through pancake ice. Directional spectral density is analyzed from in situ wave buoy data collected during a 3‐day storm event October 2015 Beaufort Sea. Two proxy metrics for obtained energy spectra, namely, significant height, are used to track as they propagate along transects array buoys predominantly ice field. types analysis compared, exhibiting differences directionality...
Abstract This study presents Arctic sea ice drift fields measured by shipboard marine X‐band radar (MR). The measurements are based on the maximum cross correlation between two sequential MR backscatter images separated ∼1 min in time, a method that is commonly used to estimate from satellite products. advantage of close temporal proximity readily available. A typical antenna rotation period ∼1–2 s, whereas revisit times can be order days. technique applied ∼4 weeks taken R/V Sikuliaq...
Abstract A storm with significant wave heights exceeding 4 m occurred in the Beaufort Sea on 11–13 October 2015. The waves and ice were captured 12 by Synthetic Aperture Radar (SAR) board Sentinel‐1A, Interferometric Wide swath images covering 400 × 1,100 km at 10 resolution. This data set allows estimation of spectra across marginal zone (MIZ) every 5 km, over sea ice. Since attenuates wavelengths shorter than 50 a few kilometers, longer are clearly imaged SAR Obtaining from image requires...
Abstract Wave attenuation from two field experiments in the ice‐covered Southern Ocean is examined. Instead of monotonically increasing with shorter waves, measured apparent rate peaks at an intermediate wave period. This “rollover” phenomenon has been postulated as result wind input and nonlinear energy transfer between frequencies. Using WAVEWATCH III ® , we first validate model results available buoy data, then use data to analyze attenuation. With choice source parameterizations used...
In April 2007 the first three‐dimensional digital terrain mapping of underside sea ice to be done from an ice‐launched autonomous underwater vehicle (AUV) was carried out at camp in Beaufort Sea using Gavia vehicle, which could launched and recovered through 3 × 1 m holes. equipped with a GeoSwath 500 kHz interferometric sonar system, yielded swaths typical width 80 m. The imagery showed morphological distinctions between first‐year (FY) multi‐year (MY) undersides, contrast shapes FY MY...
Abstract Many processes that affect ocean surface gravity waves in sea ice give rise to attenuation rates vary with both wave frequency and amplitude. Here we particularly test the possible effects of basal friction, scattering by floes, dissipation layer due dislocations, breakup waves. The influence these is evaluated marginal zone Beaufort Sea, where extensive measurements were performed. data includes situ first kilometer‐scale map heights provided Sentinel‐1 SAR imagery on 12 October...
Abstract This study presents the most comprehensive set of in situ and remote sensing measurements wave number, hence dispersion relation, ice to date. A number surface‐following buoys were deployed sea from R/V Sikuliaq , which also hosted an X‐band marine radar, during ONR Arctic Sea State field experiment. The heave‐slope‐correlation method was used estimate root‐mean‐square buoys. highly sensitive noise, extensive quality control measures developed isolate real signals estimated number....
The ice formation resulting from two low temperature events at the Weddell Sea edge during April 2000 is presented. Pancake and frazil were sampled seven stations varying distances edge. cover was further characterized above, using helicopter aerial photography, below, a remotely operated vehicle. Previously undescribed two‐layer pancake types observed classified. A novel growth mechanism introduced to account for these, involving washing of over top surface its subsequent freezing. process...
Abstract Results of helicopter-borne electromagnetic measurements total (ice plus Snow) Sea-ice thickness performed in May 2004 and 2005 the Lincoln Sea adjacent Arctic Ocean up to 86˚N are presented. Thickness distributions South 84˚N dominated by multi-year ice with modal thicknesses 3.9 m 4.2 (mean 4.67 5.18 m, respectively). Modal mean Snow on amounted 0.18 0.30 2004, 0.28 0.35 2005. There also considerable amounts 0.9–2.2m thick first-year (modal thickness), mostly representing formed...
Abstract Atmospheric flow over Antarctic sea ice was simulated applying a polar version of the fifth-generation Pennsylvania State University–National Center for Research Mesoscale Model (Polar MM5). The simulation period in late autumn lasted 48 h, starting as northerly warm airflow Weddell Sea cover and turning to southwesterly cold-air outbreak. model results were validated against atmospheric pressure wind air temperature observations made by five buoys drifting with ice. Four different...
[1] Data are presented from a survey by airborne scanning laser profilometer and an AUV-mounted, upward looking swath sonar in the spring Beaufort Sea. The air-snow (surface elevation) water-ice (draft) surfaces were mapped at 1 × m resolution over 300 area. separated into level deformed ice fractions using surface roughness of data. relation (R = d/f) between draft, d, elevation, f, was then examined. Correlation top bottom essentially zero full resolution, requiring averaging patches least...