Interannual connection of winter Barents-Kara sea-ice variability to ENSO regulated by Atlantic Multidecadal Oscillation

Abstract In this study, the impact of Atlantic Multidecadal Oscillation (AMO) on the connection of winter sea-ice concentration (SIC) over Barents-Kara Seas (BKS) to El Niño-Southern Oscillation (ENSO) is explored. It is found that the interannual connection is strengthened during the positive AMO phase (AMO+), but weakened during the negative AMO phase (AMO–). During AMO+, poleward heat and moisture transports associated with La Niña toward BKS are enhanced to cause a strong sea-ice decline via the combination of increased Ural blocking and the intensified positive phase of North Atlantic Oscillation (NAO) due to enhanced and widened Atlantic Hadley cell. Reversed results are detected during El Niño because the negative NAO and Ural trough emerge. However, the BKS SIC-ENSO connection is less evident because interannual changes in poleward atmospheric transports between La Niña and El Niño are reduced during AMO–. These results suggest that the impact of ENSO on the winter BKS SIC strongly depends on the phase of AMO.