Bushinsky Seth M, Landschützer Peter, Rödenbeck Christian, Gray Alison R, Baker David, Mazloff Matthew R, Resplandy Laure, Johnson Kenneth S, Sarmiento Jorge L
Program in Atmospheric and Oceanic Sciences Princeton University Princeton NJ USA.
Now at Department of Oceanography University of Hawai'i at Mānoa Honolulu HI USA.
Global Biogeochem Cycles. 2019 Nov;33(11):1370-1388. doi: 10.1029/2019GB006176. Epub 2019 Nov 16.
New estimates of CO from profiling floats deployed by the Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) project have demonstrated the importance of wintertime outgassing south of the Polar Front, challenging the accepted magnitude of Southern Ocean carbon uptake (Gray et al., 2018, https://doi:10.1029/2018GL078013). Here, we put 3.5 years of SOCCOM observations into broader context with the global surface carbon dioxide database (Surface Ocean CO Atlas, SOCAT) by using the two interpolation methods currently used to assess the ocean models in the Global Carbon Budget (Le Quéré et al., 2018, https://doi:10.5194/essd-10-2141-2018) to create a ship-only, a float-weighted, and a combined estimate of Southern Ocean carbon fluxes (<35°S). In our ship-only estimate, we calculate a mean uptake of -1.14 ± 0.19 Pg C/yr for 2015-2017, consistent with prior studies. The float-weighted estimate yields a significantly lower Southern Ocean uptake of -0.35 ± 0.19 Pg C/yr. Subsampling of high-resolution ocean biogeochemical process models indicates that some of the differences between float and ship-only estimates of the Southern Ocean carbon flux can be explained by spatial and temporal sampling differences. The combined ship and float estimate minimizes the root-mean-square CO difference between the mapped product and both data sets, giving a new Southern Ocean uptake of -0.75 ± 0.22 Pg C/yr, though with uncertainties that overlap the ship-only estimate. An atmospheric inversion reveals that a shift of this magnitude in the contemporary Southern Ocean carbon flux must be compensated for by ocean or land sinks within the Southern Hemisphere.
由南大洋碳与气候观测及建模（SOCCOM）项目部署的剖面浮标对一氧化碳的新估计结果表明了极地锋以南冬季脱气的重要性，这对公认的南大洋碳吸收量提出了挑战（格雷等人，2018年，https://doi:10.1029/2018GL078013）。在此，我们通过使用全球碳预算中目前用于评估海洋模型的两种插值方法（勒·奎尔等人，2018年，https://doi:10.5194/essd-10-2141-2018），将3.5年的SOCCOM观测结果置于全球表层二氧化碳数据库（表层海洋二氧化碳图集，SOCAT）的更广泛背景下，以创建仅基于船舶观测、浮标加权以及南大洋碳通量（南纬<35°）的综合估计值。在我们仅基于船舶观测的估计中，我们计算出2015 - 2017年的平均吸收量为-1.14 ± 0.19Pg C/年，与先前的研究结果一致。浮标加权估计得出南大洋吸收量显著更低，为-0.35 ± 0.19Pg C/年。高分辨率海洋生物地球化学过程模型的子采样表明，浮标和仅基于船舶观测的南大洋碳通量估计值之间的一些差异可以由空间和时间采样差异来解释。船舶和浮标综合估计值将映射产品与两个数据集之间的一氧化碳均方根差值最小化，得出南大洋新的吸收量为-0.75 ± 0.22Pg C/年，不过其不确定性与仅基于船舶观测的估计值存在重叠。大气反演表明，当代南大洋碳通量这种量级的变化必须由南半球内的海洋或陆地汇来补偿。
