摘要
利用青藏高原东北边缘的若尔盖高寒湿地生态系统研究站玛曲高寒草甸观测场提供的2010年近地面层梯度和涡动观测资料,基于Monin-Obukhov相似理论(MOST)分析了该地区风速分量、温度、水汽和CO2的归一化标准差随稳定度参数z/L在均匀平坦地表的变化关系及其季节变化特征。结果表明,风速分量σu/u*、σv/u*和σw/u*与稳定度参数z/L呈1/3次方关系,并随|z/L|增大而增大,在近中性(|z/L|<0.05)时趋于常数,且σu/u*>σv/u*>σw/u*;水平方向风速的归一化标准差随空气动力学粗糙度z0m的增大而减小,σw/u*无明显季节变化,可近似为常数;温度、水汽和CO2的归一化标准差在不稳定条件下与z/L呈-1/3次方关系,归一化值随|z/L|的减小而增大,在中性条件下σq/q*>σc/C*>σT/T*。σT/T*、σq/q*和σc/C*的季节变化分别与感热、潜热和CO2通量的季节变化相反,且主要决定于特征尺度T*、q*和C*。其中感热通量的季节变化与潜热通量、CO2通量相反,且年变化幅度最小,相应地,σT/T*的季节变化与σc/C*和σq/q*相反,且年变化幅度最小。
The relationships between normalized standard deviations of wind velocity components,temperature,water vapor,CO2 and stability parameters z /L,and their seasonal variation characteristics in the frame of MoninObukhov similarity theory( MOST) were investigated. The turbulent data were collected from an homogeneous,flat and open grassland of the northeast edge of Qinghai-Xizang Plateau in 2010. The results show that normalized standard deviation of wind velocity components generally meet 1 /3 power law. σu/v*、σv/u*and σw/v*increase along with the increase of | z /L |. Under near neutral condition( | z /L | < 0. 05),normalized standard deviations are approximate constant,and σu/u*> σv/u*> σw/u*σ. The normalized standard deviation of the horizontal wind velocity decreases with increase of aerodynamic roughness Z0m,and σw/u*does not have obvious seasonal variation,which can be regarded as a constant on the whole. Under unstable conditions,the normalized standard deviations of temperature,water vapor and CO2 in relation to z /L satisfy the similarity law,which decrease along with the increase of | z /L |. Under near neutral condition,σq/q*> σc/C*> σT/T*. The seasonal variations of σT/T*,σq/q*and σc/C*mainly depend on the seasonal change of characteristic scale T*,q*and C*,which increase with the increase of turbulent fluxes. Compared with the latent heat and CO2 flux,sensible heat flux has evidently reverse seasonal tendency,with minimal season variety and minimum value in summer. Accordingly,the extent of annual variation σT/T*is relatively small and maximum value is in summer,while σq/q*and σc/C*have reverse seasonal tendency.
出处
《高原气象》
CSCD
北大核心
2014年第3期585-595,共11页
Plateau Meteorology
基金
国家自然科学基金项目(41275016
40975008)
全球变化重大研究计划(2011CB952002)
西部之光项目(Y229C71001)
中国科学院寒区旱区环境与工程研究所青年人才成长基金项目(51Y351181)
关键词
归一化标准差
空气动力学粗糙度
季节变化
均匀下垫面
Normalized standard deviation
Aerodynamic roughness
Seasonal variation
Homogenous land surface
