摘要
利用2010年1月和6月黄土高原定西和庆阳两站大孔径闪烁仪(LAS)的观测数据,结合涡动相关系统(EC)、辐射观测、梯度塔等观测系统的同步观测资料,分析了不同下垫面LAS和EC观测感热通量的时空差异及其与下垫面净辐射、风向、风速和稳定度等物理量的关系。结果表明,LAS和EC观测感热通量值之间的差异(HLAS-HEC)大小与下垫面的不均匀性有关,相对复杂的下垫面HLAS-HEC较大。净辐射Rn是感热通量的主要驱动因子,HLAS-HEC在生长季大于非生长季,并与Rn成正相关。风向对LAS和EC观测感热通量值有显著影响。对流边界层低频涡旋的存在导致EC通量统计值偏低,HLAS/HEC随着风速的增大而减小,随着稳定度z/L的增大而增大。
On the basis of sensible heat flux data observed by Large Aperture Scintillometer( LAS) and Eddy Covariance system( EC) at Dingxi and Qingyang site for the periods of January and June 2010,the spatial and temporal differences between LAS and EC observed sensible heat flux was analyzed. Combined with radiation observing system,gradient tower and so on,the ways how the differences of LAS and EC observed sensible heat flux influenced by net radiation,wind direction,wind speed and stability was explored. The results show that the difference of sensible heat flux by LAS and EC is related to the heterogeneity of underlying surface with the difference more obvious over the more complicated underlying surface. Net radiation Rnis the main driving factor to sensible heat flux. The value of HLAS- HECin the growing season is greater than the value in the non-growing season and positively correlated with Rn. Wind direction has a significant effect on sensible heat flux by LAS and EC. The presence of low-frequency volution in convective boundary layer issues in lower flux statistics to EC,which results in that: HLAS/HECdecreases with the increasing of wind speed and increases with the increasing of z /L.
出处
《高原气象》
CSCD
北大核心
2014年第4期957-966,共10页
Plateau Meteorology
基金
国家重点基础研究发展计划(2013CB430200
2013CB430206)
国家自然科学基金重点项目(40830957)
