Spectra and cospectra of turbulence over water

Miyake, M.; Stewart, R. W.; Burling, Robbins

doi:10.1002/qj.49709640714

Cited by 109 publications

(78 citation statements)

References 5 publications

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“…For visual purposes each spectrum has been averaged using equally spaced logarithmic bins. In general, there is good agreement with the universal spectral shape of Miyake et al [1970] (dashed line) for the u and w spectra. In the inertial subrange however, values are higher than those predicted by the universal shape.…”

Section: Strong Wind Eventssupporting

confidence: 61%

“…Miyake et al [1970] demonstrated this universality over the ocean using the standard deviation of the vertical velocity s w as the scaling variable for the velocity spectra and the friction velocity for the uw cospectrum. More recently, Drennan et al [1999] confirmed these findings for fetch-limited pure wind sea conditions and found a substantial departure from the universal curves in light winds with fast swell running in the same direction.…”

Section: Strong Wind Eventsmentioning

confidence: 94%

“…The expected roughness length for underdeveloped pure wind seas was computed from wind sea Figure 11. Spectra of (a) u, (b) w, and (c) cospectrum uw for wind-sea-dominated conditions plotted in the universal scaling of Miyake et al [1970]. Lines represent the mean value for wind-sea-dominated conditions (solid line), the universal spectral shape of Miyake et al [1970] (dashed line), and the inertial subrange slope (dotted line).…”

Section: Strong Wind Eventsmentioning

confidence: 99%

“…Spectra of (a) u, (b) w, and (c) cospectrum uw for wind-sea-dominated conditions plotted in the universal scaling of Miyake et al [1970]. Lines represent the mean value for wind-sea-dominated conditions (solid line), the universal spectral shape of Miyake et al [1970] (dashed line), and the inertial subrange slope (dotted line). observed parameters, using the Drennan et al [2003] relationship.…”

Section: Strong Wind Eventsmentioning

confidence: 99%

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Wind stress in the presence of swell under moderate to strong wind conditions

et al. 2009

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[1] Wind stress is a key parameter for oceanic and atmospheric modeling, forecasting, and hydrodynamic studies. It is generally accepted that wind stress depends on the sea state. In particular, it has been shown that the presence of swell can modify both magnitude and direction of the wind stress. The presence of swell enhances momentum flux when swell propagates opposite to the wind direction and reduces it when it travels along the wind direction. However, those conclusions are mainly based on data acquired in low wind speed conditions and it is not clear to what extent an effect of swell persists at higher winds. Here simultaneous measurements of wind stress and waves, carried out in an area characterized by the occurrence of strong offshore winds with counter long-period swell, are presented and analyzed. The observations indicate that swell causes substantial changes to the wind stress at all observed wind conditions, including wind speeds as high as 20 ms À1 . It is believed that in low wind conditions swell increases drag by directly interacting with the air flow, whereas at higher winds, swell reduces drag by modifying the wind-sea-associated roughness.Citation: García-Nava, H., F. J. Ocampo-Torres, P. Osuna, and M. A. Donelan (2009), Wind stress in the presence of swell under moderate to strong wind conditions,

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Section: Strong Wind Eventssupporting

confidence: 61%

Section: Strong Wind Eventsmentioning

confidence: 94%

Section: Strong Wind Eventsmentioning

confidence: 99%

Section: Strong Wind Eventsmentioning

confidence: 99%

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Wind stress in the presence of swell under moderate to strong wind conditions

et al. 2009

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“…(1972) and over the ocean by Pond, et al (1971), Miyake, et al (1970) and Leavitt (1975). The continuous curves are for Kaimal, et al (1972), who detected slightly different limit forms for neutral stability depending on whether z/L approached zero from positive or negative values in the u' and v' spectra but not for either the w' spectrum or the u' w' co-spectrum.…”

mentioning

confidence: 99%

The measurement of the synoptic scale wind over the ocean

Pierson¹

1983

J. Geophys. Res.

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Mesoscale and microscale features of the turbulent winds over the ocean are related to the synoptic xscale winds in terms of published spectral forms for the microscale, a mesoscale valley, and published values of u*, Var u′, Var v′, and z/L, as defined in the text and as obtained for moderate to gale force winds. The frequencies involved correspond to periods longer than 1 hour and extend to the microscale, which starts at a period near 2 min, or so, and continues to the Kolmogorov inertial range. Nondimensional spectra that span both the mesoscale and the microscale are derived as a function of u*,f/(=nz/ū), and z/L, where z is 10 m, L is the Monin‐Obukhov stability length, and ū is evaluated at 10 m. For the same ū, different values of z/L produce a range of values of u* which in turn result in variations of the eddy structure of the mesoscale and microscale spectra. Both conventional anemometer averages and remotely sensed winds contain a random component of the mesoscale wind in their values. These components are differences and not ‘errors’ when winds are compared, and quantitative values for these differences are given. Ways to improve the measurement of the synoptic scale wind by transient ships, data buoys, and scatterometers on future spacecraft are described. These ways are longer averaging times for ships and data buoys, depending on the synoptic conditions, and pooling spacecraft data to form superobservations. Design considerations for future remote sensing systems are given.

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The spatial‐temporal variability of air‐sea momentum fluxes observed at a tidal inlet

et al. 2015

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Coastal waters are an aerodynamically unique environment that has been little explored from an air-sea interaction point of view. Consequently, most studies must assume that open ocean-derived parameterizations of the air-sea momentum flux are representative of the nearshore wind forcing. Observations made at the New River Inlet in North Carolina, during the Riverine and Estuarine Transport experiment (RIVET), were used to evaluate the suitability of wind speed-dependent, wind stress parameterizations in coastal waters. As part of the field campaign, a small, agile research vessel was deployed to make high-resolution wind velocity measurements in and around the tidal inlet. The eddy covariance method was employed to recover direct estimates of the 10 m neutral atmospheric drag coefficient from the three-dimensional winds. Observations of wind stress angle, near-surface currents, and heat flux were used to analyze the cross-shore variability of wind stress steering off the mean wind azimuth. In general, for onshore winds above 5 m/s, the drag coefficient was observed to be two and a half times the predicted open ocean value. Significant wind stress steering is observed within 2 km of the inlet mouth, which is observed to be correlated with the horizontal current shear. Other mechanisms such as the reduction in wave celerity or depth-limited breaking could also play a role. It was determined that outside the influence of these typical coastal processes, the open ocean parameterizations generally represent the wind stress field. The nearshore stress variability has significant implications for observations and simulations of coastal transport, circulation, mixing, and general surf-zone dynamics.

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Spectra and cospectra of turbulence over water

Abstract: SUhfMARYComposite diagrams of spectra and cospectra were constructed from eight cases of velocity Component and temperature measurements made over the water by an acoustic anemometer. Their universal form is discussed.

Cited by 109 publications

References 5 publications

Wind stress in the presence of swell under moderate to strong wind conditions

Wind stress in the presence of swell under moderate to strong wind conditions

The measurement of the synoptic scale wind over the ocean

The spatial‐temporal variability of air‐sea momentum fluxes observed at a tidal inlet

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