Abstract. We present new estimates of the regional North Atlantic (15° N–80° N) CO₂ flux for the 2000–2017 period using atmospheric CO₂ measurements from the NOAA long term surface site network in combination with an atmospheric data assimilation system (GEOSChem–LETKF). We also assess the sensitivity of flux estimates to the representation of the prior ocean flux distribution and to the associated specification of prior flux uncertainty, including a specification that is dependent on the agreement among the multiple representations of the prior ocean flux. Long term average flux estimates for the 2000–2017 period are −0.26±0.04 PgC y⁻¹ for the subtropical basin (15° N–50° N), and −0.25±0.04 PgC y⁻¹ for the subpolar region (50° N–80° N, west of 20° E). Our basin–scale estimates of the amplitude of interannual variability (IAV) are 0.037±0.006 PgC y⁻¹ and 0.025±0.009 PgC y⁻¹ for subtropical and subpolar regions respectively. We find a statistically significant trend in carbon uptake for the subtropical North Atlantic of −0.062±0.009 PgC y⁻¹ decade⁻¹ over this period.

中文翻译：

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2000–2017年期间北大西洋CO ₂通量的变化

摘要。我们使用来自NOAA长期地面站点网络的大气CO ₂测量值结合大气数据同化系统（GEOSChem），提出了2000-2017年期间北大西洋区域（15°N–80°N）CO ₂通量的新估计值–LETKF）。我们还评估了通量估计值对先验海洋通量分布的表示以及先验通量不确定性的相关规范（包括取决于先验海洋通量的多种表示之间的一致性的规范）的敏感性。2000-2017年期间的长期平均通量估计值是亚热带盆地（15°N–50°N）的-0.26±0.04 PgC y ^-1和-0.25±0.04 PgC y ^-1对于亚极地区（50°N–80°N，20°E以西）。我们对亚热带和亚极地区年际变化幅度（IAV）的盆地尺度估计分别为0.037±0.006 PgC y ^-1和0.025±0.009 PgC y ^-1。我们发现，在此期间，亚热带北大西洋的碳吸收统计趋势为-0.062±0.009 PgC y ^-1 十年^-1。