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长江流域河流CO2分压的控制因素识别与空间模拟
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Abstract:
河流的二氧化碳(CO2)排放是全球碳循环的重要组成部分。然而，各种不同的环境因子将以某种复杂的方式影响着河流的CO2排放，长江流域河流二氧化碳分压(pCO2)的主要控制因子尚不明确。本文计算了长江流域河流的pCO2并通过随机森林方法对长江流域的pCO2进行建模，识别出了与人为活动相关的因素(国民生产总值，区域人口密度，城镇和耕地覆盖率)在长江流域pCO2空间变化中发挥着重要作用。最后，使用训练好的随机森林模型模拟了0.05？ × 0.05？的空间范围下长江流域年尺度的河流pCO2空间分布，结果表明长江流域河流pCO2从上游至下游呈增加趋势，同时在2010~2018这一研究期间，河流pCO2呈下降趋势。我们认为高强度的人类活动在改变陆地碳循环的同时，也会改变河流碳循环，这将是未来实现“碳中和”目标的一个重要考虑因素。
The emission of carbon dioxide (CO2) from rivers is a critical component of the global carbon cycle. However, the environmental factors influencing riverine CO2 emissions interact in complex ways, and the key drivers of partial pressure of CO2 (pCO2) in rivers across the Yangtze River Basin remain unclear. This paper calculated riverine pCO2 in the Yangtze River Basin and modeled it using a Random Forest method. The analysis revealed that anthropogenic factors, such as gross domestic product, population density, and urban and cropland coverage, significantly contribute to the spatial variability of pCO2. Applying the trained random forest model to simulate the annual spatial distribution of riverine pCO2 at a 0.05？ × 0.05？ grid resolution across the basin, the results indicate an increasing trend in riverine pCO2 from upstream to downstream, while pCO2 exhibited a declining trend during the 2010~2018 study period. It concludes that intensive human activities, while altering the terrestrial carbon cycle, also modify the riverine carbon cycle, which will be a critical consideration for achieving future “carbon neutrality” goals.
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