A linkage between decadal climate variations in the Labrador Sea and the tropical Atlantic Ocean

According to observations, the Labrador Sea Water (LSW) thickness varies significantly on decadal time scales. Sea surface temperature (SST) in the tropical Atlantic also exhibits considerable decadal changes, including the so‐called tropical Atlantic SST dipole—a cross‐equatorial pattern. In this study, we propose that the SST dipole and variations of LSW thickness are linked through the Meridional Overturning Circulation (MOC). Southward transport of LSW along the deep western boundary must be compensated by northward flow in the upper ocean. Once the LSW pulse enters the tropics, it affects the cross‐equatorial heat transport and the upper ocean response generates a dipole pattern in the SST field. The correlation between observed LSW thickness and SST with a lag of 5 years is significant at 95% significance level. Results from an ocean model indicate that the time lag between LSW and tropical SST is set primarily by coastally‐trapped waves.