During SHEBA, thin ice and freshening of the Arctic Ocean surface in the Be
aufort Sea led to speculation that perennial sea ice was disappearing [McPh
ee Ei al., 1998]. Since 1987, we have collected salinity, delta(18)O and Ba
profiles near the initial SHEBA site and, in 1997, we ran a section out to
SHEBA. Resolving fresh water into runoff and ice melt, we found a large ba
ckground of Mackenzie River water with exceptional amounts in 1997 explaini
ng much of the freshening at SHEBA. Ice melt went through a dramatic 4-6 m
jump in the early 1990s coinciding with the atmospheric pressure field and
sea-ice circulation becoming more cyclonic. The increase in sea-ice melt ap
pears to be a thermal and mechanical response to a circulation regime shift
. Should atmospheric circulation revert to the more anticyclonic mode, ice
conditions can also be expected to revert a! though not necessarily to prev
ious conditions.