人为排放的意外减少解释了近期大气度下降的原因
Aryeh Feinberg1, Noelle E Selin1,2, Christine F Braban3
1Institute for Data, Systems, and Society, Massachusetts Institute of Technology, Cambridge, MA 02139.
概括
在北半球,大气中的 (Hg) 水平正在下降,这与排放报告相反. 这项研究表明,实际人为Hg排放量已经下降,与观察到的大气趋势保持一致.
科学领域:
- 环境化学环境化学
- 大气科学 大气科学
- 生态系统监测 生态系统监测
背景情况:
- 人类活动每年释放大约2000毫克 (Hg),导致全球大气运输和沉积.
- 尽管近几十年来北半球 (NH) Hg排放量有所增加,但NH监测站的大气Hg度显示下降趋势.
- 排放清单和观测到的大气度之间的差异可能受到遗留的Hg再排放,大气沉降动态和数据异质性的影响.
研究的目的:
- 调查北半球气态元素 (Hg0) 的观察趋势.
- 利用生物地球化学和化学运输建模来确定观察到的Hg0趋势背后的驱动因素.
- 为了调和报告的Hg排放和大气测量之间的冲突.
主要方法:
- 分析51个NH测量站的观测数据,使用线性混合效应建模.
- 应用生物地球化学盒模型和化学运输模型来模拟Hg趋势.
- 将模拟的Hg0趋势与观测数据和排放库存进行比较.
主要成果:
- 从2005年到2020年,在大多数NH地区观察到Hg0度的持续负趋势 (-0.011 ± 0.006 ng m-3 y-1).
- 建模表明,在2005年至2020年期间,NH人为Hg排放量必须减少至少140 Mg,以与观察到的大气趋势相匹配.
- 与中值相比,Hg0峰值度 (95百分位数) 的较快下降表明,当地/附近的人为排放量有所减少.
结论:
- 观察到的大气Hg0的下降与当前的全球排放库存不一致.
- 该研究表明,实际NH人为Hg排放量显著减少,这可能是由于附近来源减少而不是遗留的Hg.
- 这些发现凸显了现有的排放清单与大气观测的不兼容性,并为评估"米纳马塔公约"关于的有效性提供了关键数据.
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