一个新的1950年后的气候14C记录,用于热带地区,使用赤道亚马逊的绝对日期的树环
Guaciara M Santos1, Daniela Granato-Souza2, Santiago Ancapichún3
1Department of Earth System Science, University of California, Irvine, Irvine, CA, USA.
The Science of the total environment
|February 7, 2024
概括
来自亚马逊树林环的新大气放射性碳 (14C) 记录显示,从20世纪70年代开始,土地呼吸的二氧化碳增加了14C,比预期的更早. 这为了解全球碳预算和热带地区气候反提供了关键数据.
科学领域:
- 古气候学 古气候学
- 大气化学 大气化学
- 生态生态学 生态生态学
背景情况:
- 准确的大气放射性碳 (14C) 记录对于了解全球碳循环和气候动态至关重要.
- 现有的14C编译有空间差距,特别是在热带地区,限制了全面的全球理解.
- 热带低压带 (TLPB) 在大气循环和碳交换中发挥着重要作用.
研究的目的:
- 从1940年到2016年,为东亚马逊盆地 (EAB) 建立高精度大气14C记录.
- 通过树环数据调查1950年后的TLPB14C波动.
- 改进对14C区域变化及其对全球碳预算的影响的理解.
主要方法:
- 分析了来自Cedrela odorata的77个单一树环,通过加速器质谱法 (AMS) 获得了175个高精度的14C测量结果.
- 包括1962-1963年连续的年内环切割,以验证准确性和季节性.
- 实验室间比较和分析树木组织生长季节性,以确保数据可靠性.
主要成果:
- 从20世纪70年代开始,从陆地呼吸的二氧化碳中观察到大气14C的显著增加,比以前预测的提前十年.
- 2000年以后14C度略有下降,表明人们正在向化石燃料时代过渡.
- 与其他低度记录相比,EAB记录显示了区域差异,突出了局部的大气动态.
结论:
- EAB 14C记录填补了关键的空间空白,并有助于完善南美洲的14C变异划界.
- 研究结果表明,陆地呼吸的二氧化碳对大气贡献的变化早于预期.
- 这种扩展的热带14C记录对于重新评估全球碳预算和理解碳气候反至关重要.
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