大理涡动相关观测数据的处理及质量评价研究

依据大理国家气候观象台涡动相关仪2011年实测数据,采用目前主要的湍流通量数据处理和质量评价方法,对原始湍流数据进行一系列的预处理以及定量分析各处理步骤对湍流通量计算结果的影响,同时以湍流平稳性和通量方差相似性检验为指标对数据进行质量评价分析,并应用解析足迹模型对湍流通量观测的空间代表性进行初步分析.结果表明:对大理站来说,湍流通量计算的平均时间选取30 min为宜.剔除野点、二次坐标轴旋转、超声虚温修正、时间滞后校正、频率响应修正以及WPL修正处理会对湍流通量计算结果带来不同程度的影响,尤其是二次坐标轴旋转对动量通量以及WPL修正对CO2通量的影响较为显著.湍流平稳性和通量方差相似性检验结果显示,涡动相关通量观测数据总体质量较好,动量通量、感热通量、潜热通量以及CO2通量中高质量数据所占比例分别为59.4 %、64.2 %、63.8 %、63.2 %.湍流通量源区分析表明,源区整体呈西北东南向分布,位于测站东南方向的区域是湍流通量观测的主要贡献源区.

A study on the data processing and quality assessment of the eddy-covariance system at Dali national climate observatory

Based on the observational data of the eddy-covariance system from Dali national climate observatory in 2011,the main approaches to data processing and quality assessment recently have been selected to preprocess the orignal turbulent data and the influence on calculating turbulent flux at each processing step has been quantitatively analyzed.Meanwhile,the distribution of data quality has been analyzed on a basis of the turbulent steady state test and turbulent flux-variance similarity test,and the flux spatial representativeness of eddy-covariance system has been analyzed on a basis of analytical footprint model.The results showed that the best averaging period to calculate turbulent flux was about 30 minutes in Dali.Spike elimination,double coordinate rotation,sonic temperature correction,time-lag correction,frequency response correction and WPL correction had impact of varying degrees on calculating turbulent flux,especially on the effect of double coordinating rotation on calculating momentum flux and WPL correction on calculating carbon dioxide flux were evident.The turbulent steady state test and turbulent flux-variance similarity test revealed that overall quality of the eddy-covariance data from Dali national climate observatory was good,and the percentage of high quality data for the momentum flux,sensible heat flux,latent heat flux and carbon dioxide flux was 59.4 %,64.2 %,63.8 % and 63.2 % respectively.Footprint analysis showed that the source areas for the eddy-covariance system was in the direction from northwest to southeast and the main contribution source area was southeast area observed from the observation tower.