Zhu Chenyu, Sanchez Saray, Liu Zhengyu, Clark Peter U, He Chengfei, Wan Lingfeng, Lu Jiuyou, Zhu Chenguang, Li Lingwei, Zhang Shaoqing, Cheng Lijing
Earth System Numerical Simulation Science Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China.
College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA.
Sci Adv. 2024 Sep 20;10(38):eadp5156. doi: 10.1126/sciadv.adp5156.
Proxy reconstructions suggest that increasing global mean sea surface temperature (GMSST) during the last deglaciation was accompanied by a comparable or greater increase in global mean ocean temperature (GMOT), corresponding to a large heat storage efficiency (HSE; ∆GMOT/∆GMSST). An increased GMOT is commonly attributed to surface warming at sites of deepwater formation, but winter sea ice covered much of these source areas during the last deglaciation, which would imply an HSE much less than 1. Here, we use climate model simulations and proxy-based reconstructions of ocean temperature changes to show that an increased deglacial HSE is achieved by warming of intermediate-depth waters forced by mid-latitude surface warming in response to greenhouse gas and ice sheet forcing as well as by reduced Atlantic meridional overturning circulation associated with meltwater forcing. These results, which highlight the role of surface warming and oceanic circulation changes, have implications for our understanding of long-term ocean heat storage change.
代理重建表明，在末次冰消期期间，全球平均海表面温度（GMSST）的升高伴随着全球平均海洋温度（GMOT）相当或更大幅度的升高，这对应着较高的热储存效率（HSE；∆GMOT/∆GMSST）。GMOT的升高通常归因于深水形成区域的表面变暖，但在末次冰消期期间，冬季海冰覆盖了这些源区的大部分区域，这意味着HSE远小于1。在此，我们利用气候模型模拟和基于代理的海洋温度变化重建结果表明，末次冰消期HSE的升高是由中纬度表面变暖对温室气体和冰盖强迫的响应所导致的中间深度水域变暖以及与融水强迫相关的大西洋经向翻转环流减弱共同作用实现的。这些结果突出了表面变暖和海洋环流变化的作用，对我们理解长期海洋热储存变化具有重要意义。
