Gregory Jonathan M, Bloch-Johnson Jonah, Couldrey Matthew P, Exarchou Eleftheria, Griffies Stephen M, Kuhlbrodt Till, Newsom Emily, Saenko Oleg A, Suzuki Tatsuo, Wu Quran, Urakawa Shogo, Zanna Laure
NCAS, University of Reading, Reading, UK.
Met Office Hadley Centre, Exeter, UK.
Clim Dyn. 2024;62(3):1669-1713. doi: 10.1007/s00382-023-06989-z. Epub 2023 Dec 22.
We formulate a new conceptual model, named "2", to describe global ocean heat uptake, as simulated by atmosphere-ocean general circulation models (AOGCMs) forced by increasing atmospheric CO, as a function of global-mean surface temperature change and the strength of the Atlantic meridional overturning circulation (AMOC, ). 2 has two routes whereby heat reaches the deep ocean. On the basis of circumstantial evidence, we hypothetically identify these routes as low- and high-latitude. In low latitudes, which dominate the global-mean energy balance, heat uptake is temperature-driven and described by the two-layer model, with global-mean as the temperature change of the upper layer. In high latitudes, a proportion (about 14%) of the forcing is taken up along isopycnals, mostly in the Southern Ocean, nearly like a passive tracer, and unrelated to . Because the proportion depends linearly on the AMOC strength in the unperturbed climate, we hypothesise that high-latitude heat uptake and the AMOC are both affected by some characteristic of the unperturbed global ocean state, possibly related to stratification. 2 can explain several relationships among AOGCM projections, some found in this work, others previously reported: Ocean heat uptake efficiency correlates strongly with the AMOC. Global ocean heat uptake is not correlated with the AMOC. Transient climate response (TCR) is anticorrelated with the AMOC. projected for the late twenty-first century under high-forcing scenarios correlates more strongly with the effective climate sensitivity than with the TCR.
我们构建了一个名为“2”的新概念模型，用于描述全球海洋热量吸收情况。该模型由大气 - 海洋环流模型（AOGCMs）模拟得出，大气中二氧化碳增加作为强迫因素，全球海洋热量吸收与全球平均表面温度变化以及大西洋经向翻转环流（AMOC）强度有关。“2”模型中有两条热量进入深海的途径。基于间接证据，我们假设性地将这些途径确定为低纬度和高纬度途径。在主导全球平均能量平衡的低纬度地区，热量吸收由温度驱动，并由两层模型描述，其中全球平均[未明确的某个量]作为上层的温度变化。在高纬度地区，一部分强迫（约14%）沿着等密度面被吸收，主要在南大洋，几乎就像一个被动示踪剂，且与[未明确的某个量]无关。由于这一比例[未明确的某个量]在未受干扰的气候中与AMOC强度呈线性关系，我们假设高纬度热量吸收和AMOC都受到未受干扰的全球海洋状态的某些特征影响，可能与分层有关。“2”模型可以解释AOGCM预测之间的几种关系，有些是在本研究中发现的，有些是先前报道的：海洋热量吸收效率与AMOC密切相关。全球海洋热量吸收与AMOC不相关。瞬态气候响应（TCR）与AMOC呈反相关。在高强迫情景下预计到21世纪末的[未明确的某个量]与有效气候敏感性的相关性比与TCR的相关性更强。
