摘要
利用2014年太湖平台山站的涡度相关和小气候观测资料,优化得到(最小均方差原则)10 m中性条件下的动量交换系数(C_(D10N))、感热交换系数(C_(H10N))和水汽交换系数(C_(E10N)),分析了其季节变化特征及其与10 m高度风速(u_(10)),浪高和大气稳定度的关系,并与其他湖泊研究结果进行了对比分析。结果表明,太湖交换系数呈现冬春高、夏秋低的季节变化特征。在u_(10)<4 m/s时,交换系数随风速增加而迅速减小,在u_(10)=5~6 m/s时达到最小值后趋于稳定。受水深和风浪区限制,相同风速条件海洋参数化方案会低估太湖交换系数,低风速条件下低估更为明显。交换系数与浪高的关系类似于风速,但受水深限制,风浪发展受到制约,交换系数随浪高增加而趋于稳定。随着大气不稳定度增加,感热和水汽交换系数逐渐增大,大气不稳定或中性条件下的动量交换系数明显大于大气稳定时的结果。7个湖泊研究结果对比分析表明,湖泊形态特征对交换系数的影响较小,除Great Slave Lake外,6个内陆湖泊交换系数C_(D10N)、C_(H10N)和C_(E10N)的平均值分别为1.65×10^(-3)、1.24×10^(-3)、1.11×10^(-3)。
Based on the eddy covariance and micrometeorological observations in 2014 at the PTS site,optimized transfer coefficients of momentum（ CD10N）,heat（ CH10N） and water vapor（ CE10N） were calculated and compared with the values in other inland lakes. Seasonal variations of these transfer coefficients were investigated.Then,the relationship between the transfer coefficients and wind velocity at 10 m height,wave height and the atmospheric stability were analyzed. The results indicate that the transfer coefficients show a seasonal variation,reaching higher values in winter and spring; and lower values in summer and autumn. The transfer coefficients decreased rapidly with increasing wind speed in the weak wind（ 0 4 m / s）,reach minimum values at the wind of 5 6 m / s and then approach constant values under strong winds. Due to shallow water depth and limited wind fetch,oceanographic parameterizations would underestimate the transfer coefficients at Lake Taihu,especially in the weak wind regime. The relationship between the transfer coefficients and wave height is similar to that for wind velocity.In Lake Taihu（ mean depth 1. 9 m）,wave development is restricted by the water depth as wind velocity increasing and tends to be constant under strong winds. The transfer coefficients of heat and water vapor increase gradually with increasing atmospheric instability. The transfer coefficients of momentum under unstable and neutral conditions are much higher than those under stable conditions. Comparison of 7 inland lakes observations shows that the lake morphological characters have little impact on transfer coefficients. Excluding the Great Slave Lake,the mean CD10N、CH10Nand CE10N of other 6 lakes are 1. 65 × 10-3,1. 24 × 10-3,1. 11 × 10-3,respectively.
出处
《科学技术与工程》
北大核心
2016年第24期1-9,共9页
Science Technology and Engineering
基金
教育部长江学者和创新团队发展计划项目(PCSIRT)
江苏高校优势学科建设工程项目(PAPD)资助
关键词
太湖
湖-气交换系数
时间变化
浪高
大气稳定度
Lake Taihu
transfer coefficients
temporal variations
wave height
atmospheric stability
