半干旱区近地层动量热通量计算  

Analysis of momentum and sensible heat fluxes in surface layer in the semi-arid regions

作　　者：鲍婧[1] 张镭[1] 张燕[1] 史晋森[1] 

机构地区：[1]兰州大学半干旱气候变化教育部重点实验室大气科学学院,兰州730000

出　　处：《兰州大学学报（自然科学版）》2009年第5期63-67,共5页Journal of Lanzhou University(Natural Sciences)

基　　金：国家重点基础研究发展计划(973计划)项目(2006CB400501);国家自然科学基金项目(40675078)

摘　　要：利用兰州大学半干旱气候与环境观测站2006年12月-2007年2月铁塔观测所得的7层风、温、湿资料,采用梯度法计算了摩擦速度、摩擦温度、湍流动量通量和感热通量,并将2007年2月的通量计算值与开路涡度协方差系统观测值进行比较。结果表明:动量通量和感热通量与稳定度有密切关系,均随稳定度的增加而减小。动量通量和感热通量均有明显的日变化,中午时段最大,夜晚最小。动量通量无论在何种稳定度条件下均是由上向下输送;感热通量白天均是由下向上输送,夜间均是由上向下输送。在冬季,动量通量和感热通量的月平均值都是在12月最小,在2月最大,且动量通量的月平均值远小于感热通量的。2月的动量通量散布图斜率为1.096,相关系数R为0.761;感热通量散布图斜率为1.015,相关系数R为0.957。By using the tower observation data on wind, temperature, and humidity in the semi-arid climate and environment observatory of Lanzhou University from Dec 2006 to Feb 2007, the friction velocity, friction temperature, turbulent momentum flux and sensible heat flux were analyzed with the gradient calculation method; then the flux value was compared with the result of the eddy-covariance flux measurement in Feb 2007. The results show that the turbulent momentum flux and sensible heat flux have a Close connection with the atmospheric stability, and they both decrease with decrease of the stability. They all,have obvious diurnal variation, the biggest appears at noon and the smallest at night. The momentum fluxes are always downward transfering regardless of the stability, but sensible heat fluxes are upward transfering at daytime, and downward transfering at night. The monthly mean momentum flux and sensible heat flux-are the smallest in Dec, the largest in Feb, and the monthly mean momentum flux is far less than that of the sensible heat flux. In Feb, the slope of turbulent momentum flux scatter diagram is 1.096, and correlation coefficient is 0.761; the slope of sensible heat flux scatter diagram is 1.015, and correlation coefficient is 0.957.

关 键 词：近地层 湍流通量 稳定度 半干旱区 

分 类 号：P404[天文地球—大气科学及气象学]