期刊名称:Journal of Advances in Modeling Earth Systems
电子版ISSN:1942-2466
出版年度:2020
卷号:12
期号:12
页码:1-18
DOI:10.1029/2020MS002317
出版社:John Wiley & Sons, Ltd.
摘要:The Atlantic meridional overturning circulation (AMOC) is one of the most important
characteristics of an ocean model run. Using the depth (z) and density frameworks, we analyze how the
sinking and diapycnal transformations defining the AMOC as well as AMOC strength and variability react to
mesh refinement from low to higher resolution in two model runs driven by the CORE‐II forcing. Both
runs can represent the key locations of sinking and diapycnal transformations behind AMOC, that is,
northeastern North Atlantic. Although their spatial patterns do not change significantly with resolution
in both frameworks as the consequence of the same atmospheric forcing, the quantitative differences,
reaching several sverdrups, are seen in different locations between two model runs for both frameworks. In
particular, the refinement leads to the strongest differences in the vertical transport and diapycnal
transformations in the latitude range between 30°N and 55°N. The z framework emphasizes the role of
localized upwelling around the Gulf Stream separation site, whereas the density framework emphasizes the
contribution of (spurious) diapycnal mixing around the Grand Banks. Both effects are reduced in the
higher‐resolution run, leading to higher AMOC south of 26°N as compared to the low‐resolution run,
despite the AMOC maxima, located at high latitudes, are higher in the low‐resolution run. We suggest that
both AMOC frameworks should be used routinely in standard analyses, including forthcoming
intercomparison projects.