Subtropical Atmospheric Response to Extratropical SST Warming in the Western North Pacific Under Atmospheric Internal Variability

Abstract Sea surface temperature (SST) anomalies in the Kuroshio Extension (KE) region have been increasingly recognized as playing a key role in shaping the extratropical air–sea interactions. However, the extent to which such extratropical SST forcing can influence large‐scale atmospheric circulation and surrounding SST remains uncertain, particularly given strong atmospheric internal variability. Here, we investigate the atmospheric response to idealized positive SST anomalies in the KE region using large‐ensemble atmospheric general circulation model experiments. The imposed forcing generates a robust sea‐level pressure anomaly over and downstream of the KE, leading to surface westerly wind anomalies extending into the subtropical North Pacific. Despite substantial atmospheric internal variability over the Aleutian Low region, these subtropical wind anomalies consistently emerge across the ensemble. Our results suggest that SST forcing in the KE region can modulate air–sea interactions not only locally but also across a broader region extending equatorward.