The prominence of a tropical convective signal in the wintertime Arctic temperature

Power spectral analysis reveals that the Arctic temperature averaged over 60°N-90°N oscillates on intraseasonal time scales, centered at about 40days. We present evidence that this intraseasonal peak is strongly tied to the Madden-Julian Oscillation (MJO), the dominant mode of tropical intraseasonal variability. Although an MJO/extratropical surface air temperature relationship has been found in previous studies, our results indicate that this relationship is more prevalent than previously recognized and is strongest at the Arctic surface. This bottom-heavy temperature structure suggests that Arctic surface warming can arise from remote processes, and not necessarily from surface albedo feedback as previously argued.