青藏高原三江并流区近地表氧含量影响因素研究

Factors influencing near-surface oxygen in the Three Parallel Rivers Region of the Tibetan Plateau

  • 摘要: 缺氧威胁着高海拔地区(海拔≥2 500 m)人群的身体健康.最近的研究表明,海拔不是影响青藏高原近地表大气氧含量的唯一因子,还受到气温和植被因素的综合影响,这种影响在青藏高原典型地区尚未有记载.本研究于2019—2022年夏季沿川藏线和滇藏线对三江并流区开展野外路线考察测量,获得90个采样点数据以探索三江并流区干旱河谷近地表氧含量与海拔、植被(净初级生产力、叶面积指数、植被覆盖率、生长季节长度)、气候变量(气温,月平均降水)之间的关系.结果表明:1)气温、海拔、LAI、降水、NPP和FVC是预测三江并流区近地表氧含量的重要变量;2)海拔是影响三江并流区近地表氧含量空间变异的主要因素;3)相较于整个青藏高原,植被因素对本研究区近地表氧含量的标准化直接影响显著下降.未来应将近地表氧含量的不同驱动因素纳入地球系统模型,以减少预测氧动态及其对全球变暖的潜在反馈的不确定性.

     

    Abstract: Hypoxia threatens the health of populations at high altitudes (≥2500 meters above sea level). Recent studies have shown that altitude is not the only factor affecting near-surface atmospheric oxygen content on the Tibetan Plateau, but is also influenced by a combination of temperature and vegetation factors that have not been documented in typical areas of the Tibetan Plateau. In this study, we made field route survey measurements along the Sichuan-Xizang and Yunnan-Xizang routes in the summer of 2019-2022, and obtained data from 90 sampling points to explore the relationships between near-surface oxygen content and elevation, vegetation (net primary productivity, leaf area index, vegetation cover, length of the growing season), and climatic variables (air temperature, mean monthly precipitation) in the dry valleys of the Three Parallel Rivers Region. The results showed that: (1) temperature, elevation, LAI, precipitation, NPP and FVC were important variables in predicting near-surface oxygen content in the Three Parallel Rivers Region; (2) Elevation was the main factor influencing the spatial variability of near-surface oxygen content in the Three Parallel Rivers Region; (3) The standardized direct effect of vegetation factors on the near-surface oxygen content in the present study area was significantly reduced compared with that of the entire Tibetan Plateau. Different drivers of near-surface oxygen content should be incorporated into Earth system models to reduce uncertainty in predicting oxygen dynamics and its potential feedback to global warming.

     

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