Inter-annual variability in the tropical Atlantic from the Last Glacial Maximum into future climate projections simulated by CMIP5/PMIP3
Inter-annual variability in the tropical Atlantic from the Last Glacial Maximum into future climate projections simulated by CMIP5/PMIP3
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DOI：
10.5194/cp-14-1377-2018
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发表时间：
2018-10-01
影响因子：
4.3
通讯作者：
Wainer, Ilana
中科院分区：
文献类型：
--
作者：
Brierley, Chris;Wainer, Ilana
热带大西洋变率(TAV)在推动非洲和南美洲降雨量年复一年的变化方面发挥着重要作用。在这项研究中，通过一系列的多模型实验来研究它对全球气候变化的响应。我们在PMIP3/CMIP5多模式集合中探索了历史、末次冰盛期、中全新世和未来模拟中TAV的主要模式。尽管已知海洋表面温度存在偏差，但大多数模式都能够捕捉到热带大西洋海温变化的两个主要模式--大西洋经线模式(AMM)和大西洋纬向模式(也称为大西洋尼诺或ATL3)。这表明AMM的幅度在中全新世较小，在末次冰盛期增加，但对未来的变化含糊其辞。ATL3在最后一次冰盛期和未来的气候变化下似乎都更强，没有关于中期全新世的一致信息。受这两种模式影响的模式和区域在气候变化时稍有变化，与平均气候状态的变化相一致。在未来的气候实验中，赤道模减弱，整个北半球变暖，而南大西洋则呈现出半球范围的弱振荡格局。对于日食，AMM投射到一种类似于泛大西洋年代际振荡的模式上。纬向和经向温度梯度的幅度与它们各自的变率之间没有明显的关系。
Tropical Atlantic variability (TAV) plays an important role in driving year-to-year changes in rainfall over Africa and South America. In this study, its response to global climate change is investigated through a series of multi-model experiments. We explore the leading modes of TAV during the historical, Last Glacial Maximum, mid-Holocene, and future simulations in the multi-model ensemble known as PMIP3/CMIP5. Despite their known sea surface temperature biases, most of the models are able to capture the tropical Atlantic's two leading modes of SST variability patterns - the Atlantic Meridional Mode (AMM) and the Atlantic zonal mode (also called the Atlantic Nino or ATL3). The ensemble suggests that AMM amplitude was less during the mid-Holocene and increased during the Last Glacial Maximum, but is equivocal about future changes. ATL3 appears stronger under both the Last Glacial Maximum and future climate changes, with no consistent message about the mid-Holocene. The patterns and the regions under the influence of the two modes alter a little under climate change in concert with changes in the mean climate state. In the future climate experiment, the equatorial mode weakens, and the whole Northern Hemisphere warms up, while the South Atlantic displays a hemisphere-wide weak oscillating pattern. For the LGM, the AMM projects onto a pattern that resembles the pan-Atlantic decadal oscillation. No robust relationships between the amplitude of the zonal and meridional temperature gradients and their respective variability was found.