鼎湖山针阔叶混交林生态系统能量平衡分析

ENERGY BALANCE ANALYSIS OF THE CONIFEROUS AND BROAD-LEAVED MIXED FOREST ECOSYSTEM IN DINGHUSHAN

关键词:  鼎湖山  针阔叶混交林  能量平衡  涡度相关法

Key words:  Dinghushan  coniferous and broad-leaved forest  energy balance  eddy covariance

摘要:

能量平衡分析作为评价涡度相关法通量观测数据可靠性方法,备受学界重视。应用OLS(Ordinary least squares)和EBR(Energy Balance Ratio)2种方法,系统分析了广东省鼎湖山针阔叶混交林生态系统能量平衡特点,并分析各种涡度通量修正方法对能量平衡的影响,结果表明鼎湖山通量站平均能力平衡不闭合度为33%~47%,略高于普遍报道的不闭合度范围(10%~30%)。WPL修正、u^*订正和坐标转换,使得能量平衡闭合度有所提高,但夜间特别是冬季能量平衡较差问题依然没有得到根本解决,表明夜间弱湍流并不是导致夜间能量平衡闭合度差的主要原因。为客观评价本通量站以及ChinaFLUX能量平衡状况和通量数据质量,确定涡度相关法CO₂通量数据分析方法和改进策略提供依据。

Abstract:

As an important index to evaluate the reliability of eddy covariance measurements,energy balance analysis has been widely accepted by the community.Using two methods of OLS(Ordinary Least Squares) and EBR(Energy Balance Ratio),energy imbalance characteristics of the coniferous and broad-leaved forest ecosystem in Dinghushan were systematically analyzed in the paper.Results showed that the average energy imbalance ratio of the site was estimated as 33%~47%,which was a bit higher than the widely reported range of 10%~30%.When WPL correction,u^*-correction and terrain correction were employed,energy balance condition improved to some extent,yet the problematic situation of poor energy balance in nighttime,especially in winter season,remained unchanged even those correction methods were employed,implying that weak turbulent condition in nighttime was not the main reason for poor energy balance.The study provided a basement to evaluate energy balance closure and data quality,to formulate data processing methods and improve strategies for both the site and other forest stations of ChinaFLUX.