Statistical Modes and Physical Drivers of Multidecadal Sea Surface Temperature Variability in the Northwest Atlantic

Abstract

Variations in ocean temperature and the presence of large multidecadal sea surface temperature (SST) oscillation can have a severe impact on Northwest Atlantic ecosystems and fisheries. Differences between historical SST datasets in the regions have also been consistently noted. It is imperative that steps be taken to consider cross-dataset variability when determining patterns of variability in Northwest Atlantic SST. First, from 1901 to 2010 a novel combined-dataset approach was used along with an extended empirical orthogonal function (EEOF) analysis to determine the role of anthropogenic forcing of SST along with leading modes of variability over the Northwest Atlantic shelf and slope. Second, a mixed-layer heat budget from 1850 to 2015 was used to determine the dominant physical processes driving yearly-to-multidecadal variability across the Northwest Atlantic shelf and slope. Results from the EEOF suggest that positive Atlantic Multidecadal Oscillation (AMO) years are driven by positive North Atlantic Oscillation years (NAO).