时间序列修订对森林二氧化碳通量的影响

Impact of time series correction on forest CO_2 flux.

对长白山阔叶红松林 2 0 0 3年生长季的涡动相关实测时间序列进行了去倾修订与超声风速仪倾斜修订 ,并分析了不同修订方法对森林CO2 通量计算值的影响 .结果表明 ,基于未修订时间序列计算得到的森林CO2 通量 (Fcraw)被高估 .线性与非线性去倾对Fcraw的修订量分别为 1 6 %、1 8% ,两者差异很小 .平面拟合坐标变换与流线坐标变换对Fcraw的修订量分别为 3 7%、4 7% ,两者差异较大 .对线性去倾后的时间序列分别进行流线坐标变换与平面拟合坐标变换 ,二者对Fcraw的修订量分别为 5 5 %与 4 6 % .建议对时间序列进行线性去倾与平面拟合坐标变换综合修订 .

Detrending correction and sonic anemometer tilt correction were made to modify the raw time series measured from eddy covariance system in broad-leaved Korean pine forest of Changbai Mountains during the growing season of 2003,and the impact of different correction methods on CO 2 flux was analyzed quantificationally.The results showed that the forest CO 2 flux during growing season was overestimated when calculated from raw time series.The ratio of correction to origin flux (Fc raw) was 1.6% and 1.8% for linear and nonlinear detrend,respectively,which suggested that there was little difference between these two detrending methods.It was 3.7% and 4.7% for the planar fit coordinate transforming (PF) correction and the streamline coordinate system transforming (ST) correction,respectively,suggesting that there was a clear difference between these two sonic anemometer tilt correction methods.When detrended time series used,it was 5.5 % and 4.6% for ST correction and PF correction,respectively.It was recommended that raw time series should be corrected synthetically with linear detrend method and PF method.