Turbulent fluxes have been measured on the marine surface layer from Xisha air-sea flux tower during SCSMEX (The South China Sea Monsoon Experiment) in May 14～June 22, 1998. The preliminary results of fluctuation and gradient measurements of wind velocity, air temperature and moisture at the air-sea flux tower are presented. Intensities of turbulence are estimated to the values of σu/*S-/u@=0.096, σv/*S-/u@=0.066 and σw/*S-/u@=0.045 respectively at about 10 m high during the measured period. The drag coefficient CD of momentum transfer is approximated by the expression 103CD=0.003U210+0.020U10+0.836. And vertical fluxes of momentum, latent and sensible heat obtained from the eddy correlation or profile method are shown with various statistical quantities of turbulence structure such as friction velocity u＊ and aerodynamic roughness height z0.%1998年5月14日至6月22日，在西沙永兴岛近海铁塔上进行了一次海-气通量观测试验，观测期包括了西南季风爆发前、爆发、爆发后风速加强等几个阶段。这次试验获得该年西南季风爆发的天气特征以及由涡度相关法、廓线法计算的动量、感热、潜热通量及湍流强度等一些统计量分布。分析结果表明，观测期湍流强度σu、σv、σw与平均风速之比为0.096、0.066、0.045；在近中性条件下（z/L≈0），各相似函数基本为常数，σu/u＊≈ 3，σv/u＊≈2，σw/u＊≈1.25；在稳定条件下u、v、w三方向σ/u＊近似相等；在稳定与不稳定条件下σt/t＊随稳定度参数z/L的变化趋势相似，但符号相反。摩擦速度u＊随风速的变化接近于关系式u＊=0.029U10+0.006（U10为10 m高度30 min平均风速），空气动力粗糙度长度z0变化在0.01～0.35 mm之间。观测期动量通量变化在0.05～0.30 N/m2之间，季风爆发期明显增大；曳力系数CD平均为1.12×10-3，它随平均风速变化可以表示为关系式103CD=0.003U210+0.020U10+0.836或103CD=0.056U10+0.732。感热通量由海洋输向大气，平均值为7.8 W/m2，数值在0～15 W/m2之间变化，季风爆发后明显增大；潜热通量数值一般变化于50～200 W/m2，白天中午数值较高，夜间较低。季风爆发后也明显增大。观测期间鲍恩比（Bowen Ratio）日平均为0.05左右。
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