Mechanisms of ocean carbon cycle variability in the 21st Century
Mechanisms of ocean carbon cycle variability in the 21st Century
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21世纪海洋碳循环变化机制
DOI：
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发表时间：
2018
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影响因子：
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通讯作者：
M. Couldrey
中科院分区：
文献类型：
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作者：
M. Couldrey
海洋是大气中二氧化碳气体 (CO2) 的一个巨大且多变的汇，需要详细了解吸收变化的驱动因素来预测未来的气候变化。在这里，使用先进的海洋计算机模型将 21 世纪海洋碳循环的变化归因于潜在的因果物理、化学和生物机制。首先，北大西洋碳通量在一系列时间尺度上的变化归因于通量方程的每个组成部分：空气-海洋浓度梯度（分压差，ΔpCO2）、气体转移速度（量化环境因素，例如风如何增强气体交换，k）和溶解度系数（量化温度和盐度如何影响气体溶解，α）。 ΔpCO2 和 k 都是对年际通量变化的有力控制，但较长十年和多年的变化仅由 ΔpCO2 主导。接下来，确定北大西洋溶解无机碳 (DIC) 库存变化的驱动因素。温度和预先形成的碱度的年际变化几乎导致了流域所有DIC的逐年波动。年代际变化归因于饱和度和人为碳强迫。直到 2100 年的数十年周期和趋势以人为碳吸收为主。最后，对全球 DIC 库存差异进行了量化，强调太平洋再矿化碳的上升是年际变化的主要驱动因素。在长达 2100 年的较长时间尺度上，人为碳是造成变化的最大单一因素，其他过程起着次要或可以忽略不计的作用。
The ocean is an enormous and variable sink of carbon dioxide gas (CO2) for the atmosphere, and a detailed knowledge of the drivers of uptake variability is needed to predict future climate change. Here, a leading-edge ocean computer model is used to attribute 21st Century ocean carbon cycle variability to underlying causal physical, chemical, and biological mechanisms. First, North Atlantic carbon flux variability across a range of timescales is attributed to each component of the flux equation: the air-sea concentration gradient (the difference of partial pressures, ∆pCO2), the gas transfer velocity (which quantifies how environmental factors e.g. wind enhance gas exchange, k), and the solubility coefficient (which quantifies how temperature and salinity affect gas dissolution, α). Both ∆pCO2 and k are strong controls on interannual flux variability, but the longer decadal and multidecadal changes are dominated by just ∆pCO2. Next, the drivers of North Atlantic Dissolved Inorganic Carbon (DIC) inventory changes are identified. Interannual variations in temperature and preformed alkalinity cause almost all the basin’s year-to-year DIC fluctuations. Decadal variability is attributed to saturation and anthropogenic carbon forcing. Multidecadal cycles and the trend up to the year 2100 are dominated by anthropogenic carbon uptake. Finally, the global DIC inventory variance is quantified, highlighting Pacific up-welling of remineralised carbon as the main driver of interannual variability. Anthropogenic carbon is the largest single contributor to variability on longer timescales up to 2100, with other processes playing secondary or negligible roles.