Estimation of wind stress and heat flux over the sea surface by the inertial-dissiption method

• Main Authors: LEE,WEN HORNG, 李文鴻
• Other Authors: TSENG,RUE SHAN
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/57902233521198500058

碩士 === 國立中山大學 === 海洋資源學系 === 83 === Measurements of instantaneous wind speed and air temperature at nearly 10m above the mean sea surface as well as the sea- surface temperature were made during three cruises of R/V Ocean Researcher Ⅲ over southern Taiwna Strait. Inertial- dissipation method was used to estimate the wind stree and sensible heat flux. From spectra of wind speed and temperature it is clearly shown that the inertial subrange typically exists in high frequency band (0.5Hz-10Hz) and the -5/3 power law applies in this region. The downwind spectral value φu was found to be 3/4 times φv, the cross wind spectral value,i.e. the conditon of isotropy was satisfied. The wind spectral increases with the third power of the wind speed, and spectral value of temperature correlates well with U10n(Ts-θa), where U10n is the wind speed at 10m height under neutral condition, Ts and θa are the sea-surface and air potential temperatures respectively. Effects of atmospheric stability on momentum fluxes are especially significant under conditions of low wind and large air-sea temperature difference. Our results indicate that wind stress increase with the 7/3 power of wind speed. Neutral drag coefficent CD10n increses with increasing wind speed. Sensible heat flux has a linear relationship with U10(Ts- θa). Heat flux coefficent CT10n remains constant with varying atmospheric stability parameters under unstable stratifictions. These results are consistent wind previous studies. Finally, a time-series comparison was also made between wind stress derived from dissipation and bulk methods. Our results show that dissipation estimates of the wind stress agree well with those from bulk method and the differences are generally less than 20 percents.