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冬季夜间负净CO2通量的发生机制及合理处置的研究对于准确估算北方森林碳代谢状态具有重要影响.通过对长白山阔叶红松林2002年11月~2003年4月开路涡动相关系统获得的CO2净交换通量及相应交换过程的分析,发现(ⅰ)夜间负CO2通量主要发生在强风速条件下;(ⅱ)强风速条件下的压力脉动及平流过程是夜间负净CO2通量主要原因,鉴于对压力脉动及平流过程与CO2净交换同步实时监测的困难,提出了可操作的强风条件下CO2净交换通量的上界摩擦风速(UU)修正方法,长白山阔叶红松林的UU=0.4m·s?1,这个修正也适用于白天;(ⅲ)UU修正解决了长白山阔叶红松林冬季夜间净交换负总量问题.
The research on the mechanism and reasonable disposal of negative net CO2 flux at night in winter has an important influence on accurately estimating the carbon metabolism status of forest in northern China.Based on the open-eddy correlation system of broad-leaved Korean pine forest in Changbai Mountains from November 2002 to April 2003, CO2 net exchange fluxes and their corresponding exchange processes, it was found that (i) the nighttime negative CO2 fluxes mainly occur under strong wind speed conditions; (ii) the pressure pulsations and advection processes under strong wind speed conditions are the main negative net CO2 fluxes at night In view of the difficulty of simultaneous and real-time monitoring of pressure pulsation and advection flow and net CO2 exchange, an upper bound method for correcting the net exchange flux of CO2 under strong wind conditions is proposed. The UU = 0.4m · s -1, this amendment also applies to daytime; (iii) The UU amendment solves the problem of nighttime net net negative exchange during the winter in Changbai Mountains.