Decadal prediction of the North Atlantic subpolar gyre in the HiGEM high-resolution climate model
Decadal prediction of the North Atlantic subpolar gyre in the HiGEM high-resolution climate model
复制标题
DOI：
10.1007/s00382-017-3649-2
复制
发表时间：
2018-02
期刊：
影响因子：
4.6
通讯作者：
J. Robson;I. Polo;D. Hodson;D. Stevens;L. Shaffrey
中科院分区：
文献类型：
--
作者：
J. Robson;I. Polo;D. Hodson;D. Stevens;L. Shaffrey
本文使用 HiGEM 模型对北大西洋副极地环流 (SPG) 的初始年代际后报进行了分析，该模型的标称网格间距在大气中为 90 km，在海洋中为 1/3。 HiGEM 年代际预测 (HiGEM-DP) 在捕获 SPG 中 0-500 m 海洋热含量方面表现出出色的技能，并且在未来十年内优于历史强制瞬态积分和持久性。对北大西洋年代际变化（包括 1960 年代变冷、1990 年代中期变暖和 2005 年后变冷）的案例研究分析表明，海洋环流和热传输的变化主导了 SPG 的预测。然而，我们发现不同的过程主导了 SPG 不同区域的热含量变化。具体而言，海洋平流在东部占主导地位，而表面通量在西部占主导地位。此外，与之前的研究相比，我们发现由于 SPG 纬度的海洋环流异常，海洋热传输变化的作用较小，而对于 1960 年代的冷却，表面通量的作用较大。最后，HiGEM-DP 预测了 20 世纪 90 年代初观察到的北大西洋涛动的正状态。这些结果支持了海洋在推动北大西洋地区过去的变化中发挥的重要作用，并表明这些变化是可以预测的。
This paper presents an analysis of initialised decadal hindcasts of the North Atlantic subpolar gyre (SPG) using the HiGEM model, which has a nominal grid-spacing of 90 km in the atmosphere, and 1/3in the ocean. HiGEM decadal predictions (HiGEM-DP) exhibit significant skill at capturing 0–500 m ocean heat content in the SPG, and outperform historically forced transient integrations and persistence for up to a decade ahead. An analysis of case-studies of North Atlantic decadal change, including the 1960s cooling, the mid-1990s warming, and the post-2005 cooling, show that changes in ocean circulation and heat transport dominate the predictions of the SPG. However, different processes are found to dominate heat content changes in different regions of the SPG. Specifically, ocean advection dominates in the east, but surface fluxes dominate in the west. Furthermore, compared to previous studies, we find a smaller role for ocean heat transport changes due to ocean circulation anomalies at the latitudes of the SPG, and, for the 1960s cooling, a greater role for surface fluxes. Finally, HiGEM-DP predicts the observed positive state of the North Atlantic Oscillation in the early 1990s. These results support an important role for the ocean in driving past changes in the North Atlantic region, and suggest that these changes were predictable.