Abstract
The objective of this study was to investigate the projected Atlantic Multidecadal Oscillation (AMO) at depths inhabited by highly migratory species. This is possible using volumetric temperature data projected to 2050 at several depths (GFDL-ESM4.1). When recreating the sea surface AMO index with the ESM4.1 dataset, it was discovered that the signal did not align with others previously published. It became evident that the AMO is expressed differently, in some cases producing conflicting warm-cool phases, depending on the data source, the time scale upon which it is averaged, and the detrending methodology. The strengths and weaknesses of the types of available data (simulation-based and observation-based) and existing detrending methods are discussed. Using ESM4.1, the AMO signal was characterized at depths. Signals were analyzed for regime shifts of statistically significant warm and cool phases. Notable results include compression of the signal with depth and delayed regime shifts with depth. Signals at a peak warm and cool phase year were mapped at several depths for a spatial temperature comparison illustrating a greater temperature discrepancy at lower latitudes and towards the sea surface.