Variation of the Drag Coefficient with Wind and Wave State
Variation of the Drag Coefficient with Wind and Wave State

Author: Beverly J. Byars

Publisher:

Published: 1985

Total Pages: 122

ISBN-13:

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The dissipation method is used to obtain estimates for the friction velocity U sub *, as well as values for the neutral drag coefficient, CDN, for data collected from a coastal tower off San Diego, California. C sub DN is found to be independent of the ten-meter height windspeed, U sub 10, for velocities between 4-9 m/sec. Its value is estimated to be (0.94 + or - 0.4)1000 which compares well with values by Smith (1980) and Large and Pond (1981). Definite trends in C sub DN with fetch and sea state are also observed. Drag coefficient estimates are found to be higher for short fetch than for long fetch conditions. C sub DN is also seen to increase sharply just before frontal passages and during sea breeze conditions when the waves are actively growing. With the windspeed and wave field reaching equilibrium, C sub DN is found to decrease with time to a smaller and more constant value. (Author).

Large-Scale Oceanographic Experiments and Satellites
Large-Scale Oceanographic Experiments and Satellites

Author: C. Gautier

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 290

ISBN-13: 9400964218

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An Advanced Research Workshop (ARW) sponsored by NATO and the California Space Institute was held in Corsica (France) October 3 to 7, 1983 to discuss the role of satellite observations in the large-scal·eoceanographic experiments, especially those under discussion (e.g., the World Ocean Circulation Experiment, WOCE, and the Tropical Ocean and Global Atmosphere, TOGA). This volume is based on papers presented during that meeting, summaries of the discussions of the working groups and recommended necessary tasks to be accompl ished in preparation for WOCE and TOGA. The participants of the meeting decided that, although the collection of issues discussed in the meeting was undoubtedly incomplete, the summaries of the discussions and recommended tasks warranted being conveyed to the organizers and sponsors of WOCE and TOGA. Although not discussed at the workshop, it was recognized that an important role of satellites is as data collection and location systems. Some of the common conclusions of the different working groups discussions are that: 1) Studies are needed of the sensitivity of the ocean response to errors in surface parameters (wind stress, heat flux, SST etc.) in a variety of physical models. These should be one of the basis for determining the accuracy requirements in WOCE and TOGA.

Air-Sea Exchange: Physics, Chemistry and Dynamics
Air-Sea Exchange: Physics, Chemistry and Dynamics

Author: G.L. Geernaert

Publisher: Springer Science & Business Media

Published: 2013-04-17

Total Pages: 573

ISBN-13: 9401592918

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During the 1980's a wealth of information was reported from field and laboratory experiments in order to validate andlor modify various aspects of the surface layer Monin-Obukhov (M-O) similarity theory for use over the sea, and to introduce and test new concepts related to high resolution flux magnitudes and variabilities. For example, data from various field experiments conducted on the North Sea, Lake Ontario, and the Atlantic experiments, among others, yielded information on the dependence of the flux coefficients on wave state. In all field projects, the usual criteria for satisfying M-O similarity were applied. The assumptions of stationarity and homogeneity was assumed to be relevant over both small and large scales. In addition, the properties of the outer layer were assumed to be "correlated" with properties of the surface layer. These assumptions generally required that data were averaged for spatial footprints representing scales greater than 25 km (or typically 30 minutes or longer for typical windspeeds). While more and more data became available over the years, and the technology applied was more reliable, robust, and durable, the flux coefficients and other turbulent parameters still exhibited significant unexplained scatter. Since the scatter did not show sufficient reduction over the years to meet customer needs, in spite of improved technology and heavy financial investments, one could only conclude that perhaps the use of similarity theory contained too many simplifications when applied to environments which were more complicated than previously thought.