The North Atlantic Oscillation (NAO) influences much of the climate over the northern hemisphere. Low-Frequency Variability (LFV) in the NAO is well documented in several observational records, and recent questions in climatology speculate upon the effects that anthropogenic forcing and polar amplification might have upon the NAO. For better comprehension of North Atlantic and Arctic multi-decadal variability, it is helpful to look beyond the present day climatological context and short-term observational records.

This study uses data from the NCAR Community Climate Systems Model 3.0 (CCSM3) control simulation, to inspect the LFV of the NAO. The CCSM3 control simulation is a fully coupled (ocean, atmosphere, land, and sea ice) run with a 290-year time span, and prior work has shown the CCSM3 to be a good candidate for examining LFV associated with the NAO. In connection with NAO variability, the quality of the simulated Atlantic Water (AW) into the subsurface Arctic Ocean is evaluated. Temperature, salinity, and heat flux data are used to analyze LFV in AW, both spatially and temporally. Results concerning AW variability are discussed in comparison with observational data, and possible feedback mechanisms upon polar climate are hypothesized.