Schlunegger Sarah, Rodgers Keith B, Sarmiento Jorge L, Frölicher Thomas L, Dunne John P, Ishii Masao, Slater Richard
Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, New Jersey, USA.
Center for Climate Physics, Institute for Basic Science, Busan, South Korea.
Nat Clim Chang. 2019 Sep;9:719-725. doi: 10.1038/s41558-019-0553-2.
Attribution of anthropogenically-forced trends in the climate system requires understanding when and how such signals will emerge from natural variability. We apply time-of-emergence diagnostics to a Large Ensemble of an Earth System Model, providing both a conceptual framework for interpreting the detectability of anthropogenic impacts in the ocean carbon cycle and observational sampling strategies required to achieve detection. We find emergence timescales ranging from under a decade to over a century, a consequence of the time-lag between chemical and radiative impacts of rising atmospheric CO on the ocean. Processes sensitive to carbonate-chemical changes emerge rapidly, such as impacts of acidification on the calcium-carbonate pump (10 years for the globally-integrated signal, 9-18 years regionally-integrated), and the invasion flux of anthropogenic CO into the ocean (14 globally, 13-26 regionally). Processes sensitive to the ocean's physical state, such as the soft-tissue pump, which depends on nutrients supplied through circulation, emerge decades later (23 globally, 27-85 regionally).
气候系统中人为强迫趋势的归因需要了解这些信号何时以及如何从自然变率中显现出来。我们将出现时间诊断方法应用于一个地球系统模型的大集合，为解释海洋碳循环中人为影响的可检测性提供了一个概念框架，以及实现检测所需的观测采样策略。我们发现出现时间尺度从不到十年到超过一个世纪不等，这是大气中二氧化碳上升对海洋的化学和辐射影响之间存在时间滞后的结果。对碳酸盐化学变化敏感的过程出现得很快，例如酸化对碳酸钙泵的影响（全球综合信号为10年，区域综合为9 - 18年），以及人为二氧化碳进入海洋的入侵通量（全球为14年，区域为13 - 26年）。对海洋物理状态敏感的过程，如依赖通过环流供应的营养物质的软组织泵，则在几十年后出现（全球为23年，区域为27 - 85年）。
