Direct Measurements of Momentum and Sensible Heat Fluxes at the Tower in the Open Sea

[摘要] The results of fluctuation measurements of wind velocity and air temperature above the ocean surface at the marine observation tower are presented. And vertical fluxes of momentum and sensible heat obtained from the eddy correlation method are shown with various statistical quantities of turbulence.Intensities of turbulence are estimated to the values of σu/u=0.089, σv/u=0.060, σw/u=0.044 respectively at about 6.4m high for neutral conditions of atmosphere. The drag co-efficient CD of momentum transfer is approximated by the expression 103CD=0.36+0.118u10 for 34m/s and this coefficient is scattered in weak winds.Spectra and cospectra of turbulence are analyzed and these curves are classified into a few types according to the stability parameter z/L. In addition, it is shown from the simultaneous measurement of wind velocity and sea surface displacement that the coherence between wind and wave is too small to be recognized in moderate winds at the level of 6m height.

[学科分类] 大气科学