云贵高原西部大理地区近地层湍流特征分析  

Analyses of Turbulence Characteristics in the Surface Layer at Dali of the Western Yunnan-Guizhou Plateau

作　　者：杨智[1,2] 刘劲松[1] 朱以维[1] 董保举[1] 

机构地区：[1]大理国家气候观象台,云南大理671003 [2]云南省气象局,云南昆明650034

出　　处：《大气科学学报》2010年第1期117-124,共8页Transactions of Atmospheric Sciences

基　　金：云南省气象局青年研究基金项目(Q200610);云南省气象局短平快项目(D200807)

摘　　要：利用大理国家气候观象台2007年3—12月观测资料,采用涡动相关法等计算方法分析了该地区湍流强度、湍流方差、湍流通量等特征量的日变化和干湿季变化特征。结果表明,湍流强度干季大于湿季;湍流方差与稳定度满足1/3次方定律,风速方差在稳定条件下比不稳定条件下离散,水平方向比垂直方向离散;湍流通量有明显日变化特征,感热、动量通量干季大于湿季,潜热通量湿季大于干季,干湿季热量交换以潜热为主;干季能量闭合率大于湿季;不同风向条件下平均水汽密度存在差异。Based on the planetary boundary layer data measured by an observation system fixed on an observation tower in Dali from March to December 2007, the characteristics of turbulence intensity, standard deviation, turbulence flux and drag coefficient were analyzed by using the eddy correlation method. The results show that turbulence intensity in the dry season was much higher than that in the wet season. The dimensionless standard deviations of 3D winds followed a z/L power law with an exponent of 1/3. The dependence of the deviations on z/L in the case of stable stratification or horizontal direction was more disperse than in the case of unstable stratification or vertical direction, respectively. Turbulence fluxes displayed obvious diurnal variations both in the dry and wet seasons. The values of sensible heat flux and momentum flux were larger in the dry season;however the value of latent heat flux was larger in the wet season;and the latent heat flux always dominated over the whole period. The energy balance had obvious differences between dry and wet season, with the loss of energy much less in the dry season than in the wet season. Vapor density was different at various wind directions.

关 键 词：大理 涡动相关法 近地层 湍流特征 

分 类 号：P425.2[天文地球—大气科学及气象学]