Winter‐to‐winter recurrence and non‐winter‐to‐winter recurrence of SST anomalies in the central North Pacific

All previous studies of the winter‐to‐winter recurrence (WWR) of sea surface temperature anomalies (SSTA) have focused on mean climatic characteristics. Here, interannual variability of the SSTA WWR in the central North Pacific (CNP) is studied. The SSTA WWR displays a strong interannual variability in the CNP. The relative roles of atmospheric forcing and the oceanic reemergence mechanism are investigated by comparing SSTA WWR years and non‐WWR years. Oceanic reemergence mechanism operates every year, the SSTA in the following winter, however, depends not only on the oceanic entrainment but also the atmospheric forcing, which exhibits substantial interannual variability. During SSTA WWR years, atmospheric circulation anomalies also exhibit the WWR phenomenon. Atmospheric forcing as well as the oceanic reemergence mechanism can act synergistically to create SSTA in the following winter with the same sign. During SSTA non‐WWR years, winter atmospheric circulation anomalies do not recur in the following winter, and the following winter has opposing atmospheric forcing on SSTA. Although the reemergence mechanism is likely still operating, the anomalous heating supplied by the oceanic reemergence mechanism is smaller than that coming through the atmospheric forcing. Overall, the WWR in the CNP is an evolutional characteristic of the whole air‐sea system with the seasons, and the WWR of atmospheric circulation anomalies and its forcing play an important role in the SSTA WWR.