Stability Functions and Their Impacts on the Oceanic Boundary Layer Characteristics
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Ali Mohammadi , Saeed Farhadypoor , Ali Sheikhbahaei |
, ali.mohammadi4682@yahoo.com |
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Abstract: (8476 Views) |
The Bulk models were used for parameterization of the boundary layer in the weather forecasting
models. The accuracy of the bulk models in simulating the ocean boundary layer has been studied by many
researchers. Profile of wind in the boundary layer is roughly logarithmic and the stability functions make
the wind profile to deviate from the logarithmic profile. The stability functions have lots of effects on the
boundary layer characteristics such as monin, obukhov length. Their influences decrease with increasing
the wind speed (starting at approximately 30 ms-1). In this paper, ocean boundary layer equations are
solved for stable, unstable and neutral state conditions and the results were compared. Diagrams of friction
velocity and drag coefficient as the main features of the oceanic boundary layer were plotted. The results
showed that the drag coefficient is sensitive to the stability functions when wind speed is less than 30 ms-1.
Therefore, to achieve the required accuracy in meteorological models, the impact of the stability functions
should be considered for calculating the drag coefficient. The friction velocity of the natural and unstable
states is almost identical so we can ignore the effects of stability functions on the friction velocity during
unstable condition. Therefore, unstable friction velocity can be approximated by the neutral friction
velocity. |
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Keywords: Boundary layer, Bulk model, Stability functions, Drag coefficient, Friction velocity. |
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Full-Text [PDF 131 kb]
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Type of Study: Research/ Original/ Regular Article |
Received: 2014/12/27 | Revised: 2015/02/28 | Accepted: 2014/12/27 | ePublished: 2014/12/27
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