Stability dependence of fluxes and bulk transfer coefficients in a tropical boundary layer

Greenhut, Gary K.

doi:10.1007/bf00121670

Cited by 16 publications

(8 citation statements)

References 5 publications

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“…They found that bulk transfer coefficients increased with decreasing wind speed below about 4 m s -•. Similar results were obtained by Greenhut [ 1982] for the latent heat bulk transfer coefficient and the drag coefficient using data from aircraft flights over the equatorial eastern Pacific. Bradley Turbulence data were obtained using the Environmental Research Laboratory/National Oceanic and Atmospheric Administration gust probe system mounted on a WP-3D research aircraft [Greenhut and Gilmer, 1985].…”

Section: Introductionsupporting

confidence: 72%

Bulk transfer coefficients and dissipation‐derived fluxes in low wind speed conditions over the western equatorial Pacific Ocean

Greenhut¹,

Khalsa²

1995

J. Geophys. Res.

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Bulk transfer coefficients are derived using latent heat flux, stress magnitude, and mean quantity data obtained aboard a National Oceanic and Atmospheric Administration research aircraft flying over the far western equatorial Pacific Ocean. At wind speeds less than about 4 rn s -• the bulk transfer coefficients increase rapidly with decreasing wind speed. The validity of the inertial dissipation method for deriving turbulent fluxes in low wind speed conditions is tested using the aircraft data. At wind speeds below 4 rn s-• dissipation-derived fluxes tend to be smaller than the corresponding eddy correlation fluxes by about 10-20%.

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Section: Introductionsupporting

confidence: 72%

Bulk transfer coefficients and dissipation‐derived fluxes in low wind speed conditions over the western equatorial Pacific Ocean

Greenhut¹,

Khalsa²

1995

J. Geophys. Res.

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“…However, large variations in the values of CD were observed for the different data sets and this led to less reliable summarized data. Greenhut (1982) analyzed aircraft data for two separate regions over the eastern equatorial Pacific Ocean; he concluded that fairly good agreement with the theoretical prediction is found from CE data but too large a dependency for C, data on the unstable side. Hicks (1972) using Lake Michigan data found that the data coefficient decreased as stability increased.…”

Section: Bulk Transfer Coefficients As a Function Of The Stability Pamentioning

confidence: 94%

Stability dependence of the drag and bulk transfer coefficients over a coastal sea surface

Tsukamoto

Ohtaki

Iwatani

et al. 1991

Boundary-Layer Meteorol

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Bulk transfer coefficients were evaluated from eddy correlation flux measurements on a tixed pier during onshore winds. The mean values are C D = 1.69 x 10m3, CH = 2.58 x 1O-3 and CE = 1.51 X 10m3. The drag coefficient, C D, gradually increases with wind speed but C, and CE are independent of wind speed. According to theory and empirical formulas based on experimental results over flat grassland, the transfer coefficients should gradually increase with increasing instability. This is confirmed experimentally in the stable region in our case. However, the drag coefficient appears to decrease with increasing instability, which is against the theoretical result. A stability dependence is not clearly observed for Cn or C,.

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“…It was demonstrated in a number of field campaigns, including the Joint Air-Sea Interaction experiment (JASIN) in the North Sea in the summer of 1978 (e.g., Guymer et al 1983), the Equatorial Pacific Ocean Climate Studies (EPOCS) in the eastern equatorial Pacific in the winter of 1980 (e.g., Greenhut 1982), and the Frontal Air-Sea Interaction Experiment (FASINEX; e.g., Friehe et al 1991). The results show coupling mainly within the atmospheric boundary layer.…”

Section: Introductionmentioning

confidence: 99%

Ocean–Atmosphere Interaction over Agulhas Extension Meanders

2007

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Many years of high-resolution measurements by a number of space-based sensors and from Lagrangian drifters became available recently and are used to examine the persistent atmospheric imprints of the semipermanent meanders of the Agulhas Extension Current (AEC), where strong surface current and temperature gradients are found. The sea surface temperature (SST) measured by the Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) and the chlorophyll concentration measured by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) support the identification of the meanders and related ocean circulation by the drifters. The collocation of high and low magnitudes of equivalent neutral wind (ENW) measured by Quick Scatterometer (QuikSCAT), which is uniquely related to surface stress by definition, illustrates not only the stability dependence of turbulent mixing but also the unique stress measuring capability of the scatterometer. The observed rotation of ENW in opposition to the rotation of the surface current clearly demonstrates that the scatterometer measures stress rather than winds. The clear differences between the distributions of wind and stress and the possible inadequacy of turbulent parameterization affirm the need of surface stress vector measurements, which were not available before the scatterometers. The opposite sign of the stress vorticity to current vorticity implies that the atmosphere spins down the current rotation through momentum transport. Coincident high SST and ENW over the southern extension of the meander enhance evaporation and latent heat flux, which cools the ocean. The atmosphere is found to provide negative feedback to ocean current and temperature gradients. Distribution of ENW convergence implies ascending motion on the downwind side of local SST maxima and descending air on the upwind side and acceleration of surface wind stress over warm water (deceleration over cool water); the convection may escalate the contrast of ENW over warm and cool water set up by the dependence of turbulent mixing on stability; this relation exerts a positive feedback to the ENW-SST relation. The temperature sounding measured by the Atmospheric Infrared Sounder (AIRS) is consistent with the spatial coherence between the cloud-top temperature provided by the International Satellite Cloud Climatology Project (ISCCP) and SST. Thus ocean mesoscale SST anomalies associated with the persistent meanders may have a long-term effect well above the midlatitude atmospheric boundary layer, an observation not addressed in the past.

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Stability dependence of fluxes and bulk transfer coefficients in a tropical boundary layer

Cited by 16 publications

References 5 publications

Bulk transfer coefficients and dissipation‐derived fluxes in low wind speed conditions over the western equatorial Pacific Ocean

Bulk transfer coefficients and dissipation‐derived fluxes in low wind speed conditions over the western equatorial Pacific Ocean

Stability dependence of the drag and bulk transfer coefficients over a coastal sea surface

Ocean–Atmosphere Interaction over Agulhas Extension Meanders

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