Aquaplanet experiments with periodically time-varying Qflux, links to supplementary material

We conduct a suite of two experiments by employing an idealized general circulation model to examine how extratropical thermal forcing confined to one hemisphere affects the other hemisphere. The employed model is based on the Geophysical Fluid Dynamics Laboratory Atmospheric Model 2 (AM2), coupled to an aquaplanet slab ocean model with approximately 50 m depth, and governed under perpetual equinox insolation and without sea-ice. One experiment simulates the impact of thermal forcing confined in one high-latitude, north of 40°N, periodically time-varying Qflux, representing a low-frequency polar variability, called PERI. The high-latitude forced variability is propagated into the tropics and the opposite hemisphere. The distinct climate response in the opposite hemisphere is deniable evidence of pole-to-pole teleconnection via zonal-mean atmospheric dynamics. The other experiment is similarly conducted with PERI, but southern mid-to-high latitude is nudged into the climatology, denoted as FSST. This partially fixed SST experiment only removes the influence on the tropics from the southern extratropics, hence a comprehensive tool to understanding the sequence of pole-to-pole teleconnection captured in PERI. This is not only the ideal result to explore the role of high-latitude low-frequency variability, but also a useful benchmark to examine sequential pathways for high-latitude variability.