Sea–air CO 2 fluxes in the Southern Ocean for the period 1990–2009
Sea–air CO 2 fluxes in the Southern Ocean for the period 1990–2009
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DOI：
10.5194/bg-10-4037-2013
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发表时间：
2013-06
期刊：
影响因子：
4.9
通讯作者：
A. Lenton;B. Tilbrook;R. Law;D. Bakker;S. Doney;N. Gruber;M. Ishii;M. Hoppema;N. Lovenduski;R. Matear;B. Mcneil;N. Metzl;S. M. Fletcher;P. Monteiro;C. Rödenbeck;C. Sweeney;Taro Takahashi
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文献类型：
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作者：
A. Lenton;B. Tilbrook;R. Law;D. Bakker;S. Doney;N. Gruber;M. Ishii;M. Hoppema;N. Lovenduski;R. Matear;B. Mcneil;N. Metzl;S. M. Fletcher;P. Monteiro;C. Rödenbeck;C. Sweeney;Taro Takahashi
南大洋（44° S-75° S）在全球碳循环中发挥着关键作用，但仍然是采样最少的海洋区域之一。不同的方法已被用来估计海-气CO2通量在这一地区：合成的表面海洋观测，海洋生物地球化学模型，大气和海洋逆温。作为RECCAP（区域碳循环评估和过程）项目的一部分，我们联合收割机这些不同的方法来量化和评估1990-2009年之间南大洋海-气CO2通量的大小和变化。使用所有模式和反演（26），44° S-75° S区域的综合年中位海-气CO2通量为-0.42 ± 0.07 Pg C yr-1，与使用地面观测计算的-0.27 ± 0.13 Pg C yr-1一致。58° S以南的环极区年净通量较小（模式和反演中值：-0.04 ± 0.07 Pg C yr-1，观测值：+0.04 ± 0.02 Pg C yr-1），大部分净年通量位于44° S至58° S的环极带（模型和反演中位数：-0.36 ± 0.09 Pg C yr-1，观察值：-0.35 ± 0.09 Pg C yr-1）。在季节上，5个海洋地球化学模式的中值反映了44° S-58° S区域海气CO2通量的季节变化，而11个大气逆温模式的中值反映了海气CO2净通量的季节变化。在58° S以南，无论是大气逆温还是海洋地球化学模式都不能再现观测到的季节性海-气CO2通量的相位和振幅，特别是在南方冬季。重要的是，没有一个单独的大气逆温或海洋地球化学模型能够再现观测到的年平均吸收和观测到的季节性周期。这引起了人们对预测南大洋CO2通量未来变化的关切。大气逆温和海洋生物地球化学模型的年际变化中值在南大洋很大;高达年平均通量的25%，其中25%的年际变化归因于58° S以南的区域。从逆温和模型的净CO2通量的趋势是没有统计学差异的预期增加-0.05 Pg C年-1十年-1由于大气CO2浓度的增加。然而，解决长期趋势是困难的，由于大的年际变化和短的时间框架（1990-2009年）的这项研究。
The Southern Ocean (44° S-75° S) plays a critical role in the global carbon cycle, yet remains one of the most poorly sampled ocean regions. Different approaches have been used to estimate sea-air CO2 fluxes in this region: synthesis of surface ocean observations, ocean biogeochemical models, and atmospheric and ocean inversions. As part of the RECCAP (REgional Carbon Cycle Assessment and Processes) project, we combine these different approaches to quantify and assess the magnitude and variability in Southern Ocean sea-air CO2 fluxes between 1990-2009. Using all models and inversions (26), the integrated median annual sea-air CO2 flux of -0.42 ± 0.07 Pg C yr-1 for the 44° S-75° S region is consistent with the -0.27 ± 0.13 Pg C yr-1 calculated using surface observations. The circumpolar region south of 58° S has a small net annual flux (model and inversion median: -0.04 ± 0.07 Pg C yr-1 and observations: +0.04 ± 0.02 Pg C yr-1), with most of the net annual flux located in the 44° S to 58° S circumpolar band (model and inversion median: -0.36 ± 0.09 Pg C yr-1 and observations: -0.35 ± 0.09 Pg C yr-1). Seasonally, in the 44° S-58° S region, the median of 5 ocean biogeochemical models captures the observed sea-air CO2 flux seasonal cycle, while the median of 11 atmospheric inversions shows little seasonal change in the net flux. South of 58° S, neither atmospheric inversions nor ocean biogeochemical models reproduce the phase and amplitude of the observed seasonal sea-air CO2 flux, particularly in the Austral Winter. Importantly, no individual atmospheric inversion or ocean biogeochemical model is capable of reproducing both the observed annual mean uptake and the observed seasonal cycle. This raises concerns about projecting future changes in Southern Ocean CO2 fluxes. The median interannual variability from atmospheric inversions and ocean biogeochemical models is substantial in the Southern Ocean; up to 25% of the annual mean flux with 25% of this inter-annual variability attributed to the region south of 58° S. Trends in the net CO2 flux from the inversions and models are not statistically different from the expected increase of -0.05 Pg C yr-1 decade-1 due to increasing atmospheric CO2 concentrations. However, resolving long term trends is difficult due to the large interannual variability and short time frame (1990-2009) of this study.