Emergence of Anthropogenic Signals in the Ocean Carbon Cycle
Emergence of Anthropogenic Signals in the Ocean Carbon Cycle
复制标题
海洋碳循环中人为信号的出现
作者：
S. Schlunegger;K. Rodgers;J. Sarmiento;T. Frölicher;J. Dunne;M. Ishii;R. Slater
对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出现。我们将涌现时间诊断应用于地球系统模型的一个大集合，这为解释海洋碳循环中人为影响的可探测性和实现探测所需的观测采样策略提供了一个概念框架。我们发现出现的时间尺度从不到十年到一个多世纪不等，这是大气中二氧化碳上升对海洋的化学和辐射影响之间的时间差的结果。对碳酸盐化学变化敏感的过程迅速出现，如酸化对碳酸钙泵的影响（全球综合信号为10年，区域综合信号为9-18年）和人为CO2进入海洋的入侵通量（全球14年，区域13-26年）。对海洋物理状态敏感的过程，如依赖于通过循环提供的营养物质的软组织泵，在几十年后才出现（全球23年，区域27-85年）。海洋碳循环的组成部分将对气候变化做出不同的反应，人为影响首先出现在对化学变化敏感的过程上——碳酸钙泵和海洋对二氧化碳的吸收——随后出现的是软组织泵（对海洋的物理状态敏感）。
The attribution of anthropogenically forced trends in the climate system requires an understanding of when and how such signals emerge from natural variability. We applied time-of-emergence diagnostics to a large ensemble of an Earth system model, which provides 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 found emergence timescales that ranged from less than a decade to more than a century, a consequence of the time lag between the chemical and radiative impacts of rising atmospheric CO2 on the ocean. Processes sensitive to carbonate chemical changes emerge rapidly, such as the impacts of acidification on the calcium carbonate pump (10 years for the globally integrated signal and 9–18 years for regionally integrated signals) and the invasion flux of anthropogenic CO2 into the ocean (14 years globally and 13–26 years 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 years globally and 27–85 years regionally).The components of the ocean carbon cycle will respond differently to climate change, with anthropogenic impacts first seen on processes sensitive to chemical changes—the calcium carbonate pump and oceanic uptake of CO2—with the soft-tissue pump (sensitive to the ocean’s physical state) emerging later.