arXiv subjects

W. Erick Rogers

Publications and source records attributed to W. Erick Rogers.

8 recordsLinked to original sources

arXiv2026

Ice-thickness based scaling of wave attenuation in sea ice: Application and assessment of wave spectra

This study discusses recent advances in modeling waves in sea ice in the U.S. Navy's regional modeling system. It is applied in the marginal seas of the eastern Arctic Ocean, including the Barents Sea, Kara Sea, parts of the Greenland Sea, Norwegian Sea, and waters north of Svalbard. The focus is to assess the skills of two formulations of wave attenuation by sea ice used operationally in WAVEWATCH III. Both are derived from large field datasets, one from the Arctic and the other from the Antarctic. The new model (IC4M9) describes wave attenuation depending on the ice thickness in association with the dependence on wave frequency, while the earlier default scheme (IC4M6) omits the dependence on ice thickness. The modeling results are evaluated against the satellite wave observations from SWIM/CFOSAT and the buoy measurements from the Svalbard Marginal Ice Zone 2024 Campaign (SvalMIZ-24). The comparisons with SWIM data validate the wave model skill in regions of open water or with light ice coverage. When evaluated against the SvalMIZ-24 data, the statistical performance of IC4M9 is substantially better than that of IC4M6, showing the influence of ice thickness on waves in the MIZ. Moreover, diagnosing systematic errors in the predictions by IC4M9, we find that the ice thickness field provided by the sea ice model CICE to the wave model is biased high in the MIZ, thus penalizing the performance of IC4M9 while not affecting the model IC4M6, which depends on frequency only.

physics.ao-ph↗

arXiv2026

Implications of Doppler shift for High Frequency Ocean Waves Measured Using Drifting Buoys

The advent of expendable wave buoys has greatly expanded the data available for evaluating and calibrating wave models. Ideally, the newer buoys now drifting around the world's oceans would be merged with conventional time series measurements from moored buoys to form a consistent dataset of in situ observations. However, a comparison across several buoy types (moored Datawell, moored NDBC, and two types of drifting buoys) suggests large differences in the high frequency portion of the observed wave energy spectra (0.2 to 0.6 Hz). When binned by wind speed, the moored Datawell buoys have higher energy in the high frequency tail vs. drifting buoys, by factor 1.2 to 1.6. The moored Datawell buoys also have far better agreement with high-frequency energy levels predicted by a numerical wave model. The key to the difference appears to be the reference frame of the observations. To test this hypothesis, the spectra are adjusted from the drifting reference frame to the fixed reference frame. The adjustment is a two-step process, in which the buoy-observed frequencies are first shifted to an intrinsic reference frame, providing wavenumber at each frequency, and then the drifter-observed spectrum is Doppler shifted to the fixed reference frame. Two methods for estimation of buoy drift are tested; one is based on wind speed, and one is based on buoy positions. With this adjustment, the observations from the drifting buoys become more consistent with the moored Datawell buoys, though discrepancies still exist with the moored NDBC buoys.

physics.ao-ph↗

arXiv2026

Buoy observation of high frequency ocean wave energy: accuracy, consistency, and concerns for predictive applications

Observational data from buoys are of primary importance during the development, calibration, and evaluation of ocean wave models, and these data are also used to make real-time corrections to operational models via data assimilation. By association, systematic inaccuracies in any buoy data are equally important, and thus when two buoy types provide systematically inconsistent information, this is a concern for anyone using an ocean wave model. This report is concerned with the accuracy of the high frequency portion of the ocean wave spectrum commonly observable by buoys, roughly 0.2 to 0.6 Hz. We evaluate four buoy types (two moored, two drifting) using two quantitative measures. The first involves comparing each type with a co-located ocean wave model. The second method involves evaluation of high frequency energy level as a function of wind speed. Both evaluation methods suggest that the Datawell Waverider (DWR) buoys have a strong tendency to report higher energy levels than the other three buoy types. We evaluate high frequency energy level using three different metrics (mean square slope, energy in a band of high frequencies, and spectral density at a single, specific band, 0.4 Hz), and the conclusions are found to be insensitive to the parameter used.

physics.ao-ph↗

arXiv2024

Utility of ocean wave parameters in ambient noise prediction

This study is concerned with prediction of the "wind noise" component of ambient noise (AN) in the ocean. It builds on the seminal paper by Felizardo and Melville (1995), in which the authors quantified the correlation between AN and individual wind/wave parameters. Acoustic data are obtained from hydrophones at six diverse locations, and wind/wave parameters are obtained from moored buoys and numerical models. We describe a procedure developed for this study which identifies correlation of AN with wave parameters, independent of their mutual correlation with wind speed. We then describe paired calibration/prediction experiments, whereby multiple wind/wave parameters are used simultaneously to estimate AN. We find that the improvement from inclusion of wave parameters is robust but marginal: typically RMSE is reduced by less than 0.3 dB and/or less than 12% of the original RMSE. We interpret the latter outcome as suggesting that wave breaking responds to changes in local winds quickly, relative to, for example, total wave energy, which develops more slowly. This outcome is consistent with prior knowledge of the physics of wave breaking, e.g. Babanin (2011). We discuss this in context of the time/space response of various wave parameters to wind forcing.

physics.ao-ph↗

arXiv2021

Incorporating dependence on ice thickness in empirical parameterizations of wave dissipation by sea ice

This study is part of an effort to improve the Navy's ability to forecast wind-generated ocean waves in ice-infested regions, and here we are attempting to further this goal by improving prediction of dissipation of wave energy by sea ice. Rogers et al. (2021) presented new estimates of frequency-dependent dissipation of wave energy by sea ice, based on model-data inversion, and studied the correlation with various other parameters, such as ice thickness and sea state variables. Here, we use that dataset to propose a new dissipation parameterization which explicitly incorporates the dependence on the ice thickness, in addition to the wave frequency. The goal is to determine whether a parameterization dependent on wave frequency and ice thickness can be more accurate than one dependent only on wave frequency. Due to the dominant impact of frequency and confounding difficulties of field measurements, this is not a foregone conclusion. A parameterization is developed using the non-dimensionalization approach proposed by Yu et al. (2019). We find that the non-dimensionalization does result in significant scale collapse of the data, and inclusion of ice thickness does improve accuracy, most evidenced by reduced scatter when applied to the same dataset. However, evaluations against independent datasets are mixed. Possible reasons for this are discussed.

physics.ao-ph↗

arXiv2020

Estimates of dissipation of wave energy by sea ice for a field experiment in the Southern Ocean, using model/data inversion

A model-data inversion is applied to a very large observational dataset collected in the Southern Ocean north of the Ross Sea during late autumn to early winter, producing estimates of the frequency-dependent rate of dissipation by sea ice. The modeling platform is WAVEWATCH III(R) which accounts for non-stationarity, advection, wave generation, and other relevant processes. The resulting 9477 dissipation profiles are co-located with other variables such as ice thickness to quantify correlations which might be exploited in later studies to improve predictions. Mean dissipation profiles from the inversion are fitted to simple binomials. Variability about the mean profile is not small, but the binomials show remarkable qualitative similarity to prior observation-based estimates of dissipation, and the power dependence is consistent with at least three theoretical models, one of which assumes that dissipation is dominated by turbulence generated by shear at the ice-water interface.

physics.ao-ph↗

arXiv2019

Progress during the NOPP Wave Model Improvement Program

This paper reviews the research activities that were carried out under the auspices of the National Ocean Partnership Program (NOPP) to advance research in wind wave modeling and transfer maturing technologies into operational community models. Primary focus of research activities that were funded under this program was to improve the source terms associated with deep water wind waves with a secondary focus on shallow water processes. While the focus has been on developing capabilities for stochastic phase averaged models, some of the research work reported here also touches on phase resolved models as well as updates that are needed to the classical stochastic equations to be applicable in shallow water conditions. The primary focus is on the development of new source terms to account for wave generation, dissipation and nonlinear wave-wave interactions. A direct result of this program has been the development of new physics packages in operational wave models that have improved forecast skill from 30 to 50 percent. Since this is an overview paper summarizing all the activities that were undertaken under this program, only the major results are presented here. The readers are directed to other publications for more details. The paper ends with a discussion of the remaining major challenges in wind wave modeling, from the larger open ocean scales to the smaller coastal domains.

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arXiv2019

Bimodal directional propagation of wind-generated ocean surface waves

Over the years, the directional distribution functions of wind-generated wave field have been assumed to be unimodal. While details of various functional forms differ, these directional models suggest that waves of all spectral components propagate primarily in the wind direction. The beamwidth of the directional distribution is narrowest near the spectral peak frequency, and increases toward both higher and lower frequencies. Recent advances in global positioning, laser ranging and computer technologies have made it possible to acquire high-resolution 3D topography of ocean surface waves. Directional spectral analysis of the ocean surface topography clearly shows that in a young wave field, two dominant wave systems travel at oblique angles to the wind and the ocean surface display a crosshatched pattern. One possible mechanism generating this bimodal directional wave field is resonant propagation as suggested by Phillips resonance theory of wind wave generation. For a more mature wave field, wave components shorter than the peak wavelength also show bimodal directional distributions symmetric to the dominant wave direction. The latter bimodal directionality is produced by Hasselmann nonlinear wave-wave interaction mechanism. The implications of these directional observations on remote sensing (directional characteristics of ocean surface roughness) and air-sea interaction studies (directional properties of mass, momentum and energy transfers) are significant.

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