Eddy flux corrections for CO_2 exchange in broad-leaved Korean pine mixed forest of Changbai Mountains  

作　　者：WU Jiabing, GUAN Dexin, SUN Xiaomin, YU Guirui, ZHAO Xiaosong, HAN Shijie & JIN Changjie Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China Graduate school of the Chinese Academy of Sciences, Beijing 100093, China Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China 

出　　处：《Science China Earth Sciences》2005年第z1期106-115,共10页中国科学（地球科学英文版）

基　　金：This work was supported by the National Key Basic Research Development Program of China(Grant No.2002CB412502);the National Natural Science Foundation of China(Grant No.30370293);the Knowledge Innovation Project of the Chinese Academy of Sciences(Grant No.KZCX1-SW-01-0lA);the Frontier Project of Institute of Applied Ecology,Chidemy of Sciences.

摘　　要：Based on analysis of mechanisms causing energy no-closure and nocturnal low fluxes issues for CO2 exchange studies by eddy covariance method, corrections were done with the raw data sets obtained from Changbai Mountains forest flux site, to evaluate the impacts of sonic anemometer tilt, frequency response limitations and advection on estimation of CO2 exchange, respectively. The results show that the planar fit coordinate transforming method is superior to the streamline coordinate transforming method in tilt correction. The latter could cause a systematical underestimation of eddy fluxes relating with the angle of sensor and terrain tilt. The underestimation of CO2 and energy fluxes for frequency response limitations average 3.0% and 2.0% during daytime, respectively, which increase by 9.0% and 5.5% during nighttime, respectively. The corrections of frequency response limitations are closely related to atmospheric stability. The advection loss of CO2 fluxes is dominated by nocturnal vertical advection, which is at least 18% when the horizontal advection is neglected. It is suggested that more work be done to understand the characteristics of horizontal advection and turbulent eddies under a complexcircumstance.Based on analysis of mechanisms causing energy no-closure and nocturnal low fluxes issues for CO2 exchange studies by eddy covariance method, corrections were done with the raw data sets obtained from Changbai Mountains forest flux site, to evaluate the impacts of sonic anemometer tilt, frequency response limitations and advection on estimation of CO2 exchange, respectively. The results show that the planar fit coordinate transforming method is superior to the streamline coordinate transforming method in tilt correction. The latter could cause a systematical underestimation of eddy fluxes relating with the angle of sensor and terrain tilt. The underestimation of CO2 and energy fluxes for frequency response limitations average 3.0% and 2.0% during daytime, respectively, which increase by 9.0% and 5.5% during nighttime, respectively. The corrections of frequency response limitations are closely related to atmospheric stability. The advection loss of CO2 fluxes is dominated by nocturnal vertical advection, which is at least 18% when the horizontal advection is neglected. It is suggested that more work be done to understand the characteristics of horizontal advection and turbulent eddies under a complex circumstance.

关 键 词：EDDY COVARIANCE method  carbon cycle  flux correction  CO2 exchange  TILT correction. 

分 类 号：Q948.1[生物学—植物学]