Tang Yakun, Wen Xuefa, Sun Xiaomin, Wang Huimin
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China ; University of Chinese Academy of Sciences, Beijing, China.
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.
PLoS One. 2014 Feb 10;9(2):e88267. doi: 10.1371/journal.pone.0088267. eCollection 2014.
The interannual variation of the Bowen ratio, through its effect on the warming extent of available energy to the ecosystem land surface air, heavily influences the ecosystem microclimate and affects the hydrological cycle at both regional and global scales. Although the precipitation amount in southeast China is not expected to change greatly as a result of climate change, the precipitation frequency may be altered in the future. We explored the interannual variation of the Bowen ratio and its affecting mechanisms based on eddy covariance measurements in a subtropical plantation in southeast China during 2003-2012. The results indicated that the annual mean Bowen ratio was 0.35 ± 0.06, with a range of 0.29-0.45. The Bowen ratio during the dry season (July-October) positively correlated with the annual Bowen ratio (R(2) = 0.85, p<0.001). The effective precipitation frequency during the dry season, through its positive effect on shallow soil water content, indirectly and negatively affected the annual Bowen ratio. Between 2003 and 2012, the annual Bowen ratio exhibited a marginally significant decreasing trend (p = 0.061), meanwhile the effective precipitation frequency and shallow soil water content during the dry season increased significantly (p<0.001). The annual Bowen ratio may decrease further if the effective precipitation frequency and shallow soil water content during the dry season follow similar trends in the future. The warming effect of available energy to the surface air of our studied plantation may decline with the decreasing annual Bowen ratio.
鲍文比的年际变化，通过其对生态系统陆地表面空气可利用能量升温程度的影响，严重影响生态系统小气候，并在区域和全球尺度上影响水文循环。尽管预计气候变化不会使中国东南部的降水量发生大幅变化，但未来降水频率可能会改变。我们基于2003 - 2012年中国东南部一个亚热带人工林的涡度相关测量数据，探讨了鲍文比的年际变化及其影响机制。结果表明，年平均鲍文比为0.35±0.06，范围为0.29 - 0.45。旱季（7 - 10月）的鲍文比与年鲍文比呈正相关（R² = 0.85，p<0.001）。旱季的有效降水频率通过对浅层土壤含水量的正向影响，间接且负向地影响年鲍文比。在2003年至2012年期间，年鲍文比呈现出微弱的显著下降趋势（p = 0.061），与此同时，旱季的有效降水频率和浅层土壤含水量显著增加（p<0.001）。如果未来旱季的有效降水频率和浅层土壤含水量遵循类似趋势，年鲍文比可能会进一步下降。随着年鲍文比的降低，我们研究的人工林地表空气可利用能量的升温效应可能会减弱。
