Li Han Zhi, Yu Xin Xiao, Jia Guo Dong, Zhao Na, Liu Zi Qiang, Lu Wei Wei, Zhang Yong E
Beijing Forestry University, Beijing 100083, China.
Ying Yong Sheng Tai Xue Bao. 2017 Jul 18;28(7):2164-2170. doi: 10.13287/j.1001-9332.201707.014.
This research employed off-axis integrated cavity output spectroscopy technique to observe CO concentration and δC values of planted Platycladus orientalis in Beijing mountainous area. We compared the variation between CO concentration and δC values in the plantation at different heights observed by every 0.5 h to explore how the CO concentration and δC values responded to the meteorological factors. The results showed that the CO concentration showed the pattern of "first decreased and then increased" after sunrise. The lowest value (352.5 μmol·mol) appeared at 16:00-16:30, while the maximum value (402.0 μmol·mol) was observed at about 5:00. However, the change of δC value was not significant and regular, which increased firstly and then decreased in the surface layer while opposite for the canopy. Atmospheric CO concentration decreased with the increasing height. In the height of 0, 2, 5, 8, 12.5 and 18 m, the average daily value was 386.5, 369.9, 368.2, 367.8, 367.9 and 367.9 μmol·mol, respectively. In contrast, the δC values tended to rise correspondingly with height with the average daily value being -16.0‰, -13.7‰, -13.5‰, -13.5‰, -13.1‰ and -13.3% at 0, 2, 5, 8, 12.5 and 18 m, respectively. The stepwise regression analysis showed that temperature and humidity were the main factors for the changes of atmospheric CO concentration and δC values. The saturated vapor pressure difference (VPD) affected the concentration of CO in the forest and wind speed could affect it on the canopy. However, soil moisture, soil electric conductivity and net solar radiation affected the CO concentration and δC values in surface layer. All these environmental factors influenced CO concentration and δC values through their influences on the photosynthesis and respiration.
本研究采用离轴积分腔输出光谱技术观测北京山区人工油松的CO浓度和δC值。我们比较了每隔0.5小时在不同高度观测到的人工林中CO浓度和δC值的变化，以探究CO浓度和δC值对气象因素的响应情况。结果表明，日出后CO浓度呈“先下降后上升”的趋势。最低值（352.5 μmol·mol）出现在16:00 - 16:30，而最高值（402.0 μmol·mol）出现在约5:00。然而，δC值的变化不显著且无规律，表层先升高后降低，而冠层则相反。大气CO浓度随高度增加而降低。在0、2、5、8、12.5和18米高度处，日均值分别为386.5、369.9、368.2、367.8、367.9和367.9 μmol·mol。相比之下，δC值随高度相应升高，在0、2、5、8、12.5和18米处的日均值分别为-16.0‰、-13.7‰、-13.5‰、-13.5‰、-13.1‰和-13.3%。逐步回归分析表明，温度和湿度是大气CO浓度和δC值变化的主要因素。饱和水汽压差（VPD）影响森林中CO的浓度，风速则对冠层的CO浓度有影响。然而，土壤湿度、土壤电导率和净太阳辐射影响表层的CO浓度和δC值。所有这些环境因素通过对光合作用和呼吸作用的影响来影响CO浓度和δC值。
