On the role of the NAO in the recent northeastern Atlantic Arctic warming

[1] Studies such as those by Zhang et al. [1998] and Peterson et al. [2003] suggest that the northeastern Atlantic Arctic warmed in the early 1990s and that regional sea level pressure (SLP) variations and the NAO may be responsible. Sea surface temperature changes in Fram Strait and the Barents Sea depend, respectively, on SLP variations over the Barents Sea and Norwegian Sea. Since winter 1972, SLP over the Barents and Norwegian Seas has been unusually low during NAO+ winters. Little pressure field change occurred during NAO- winters or around the Denmark Strait, the normal location of the Icelandic Low. Simultaneously, the NAO+ mode became highly persistent on a month-to-month basis throughout the NAO+ winters and ultimately throughout all seasons during a multiyear episode in which the Arctic reached peak warming. A similar NAO+ persistence episode is shown to have occurred from 1920 - 1925, during another notable Arctic warming event.