Fourteen years of variability in the meteoric water, sea-ice melt, and Pacific water contributions to the central Arctic Ocean: 2000-2014

Abstract:

More than a decade of observations of water type composition (meteoric water, net sea-ice meltwater, Pacific and Atlantic seawater) in the mixed layer of the Central Arctic Ocean were compiled from data collected during the North Pole Environmental Observatory program. Although no large changes were apparent in the total freshwater inventory, a decline in the inventory of meteoric water (-600 km³ yr^-1) between 2000 and 2012 was somewhat offset by a concomitant increase in the net sea-ice meltwater (300 km³ yr^-1) contribution to the total freshwater volume of the North Pole region. In more recent years (2013-2014), both meteoric water and sea-ice melt contributions have reverted back toward values reminiscent of the late 1990s/early 2000s.

The loss of meteoric water from the Central Arctic generally agreed with hypotheses that suggest the recent freshwater increase observed in Canada Basin was due, in part, to a diversion of Siberian river runoff from the Central to Western Arctic. In contrast, the average annual increase in net sea-ice melt was approximately equal to the long-term decline in the sea ice volume anomaly. Although no trend was apparent in the Pacific water influence, two separate events resulted in relatively brief (1-3 years) returns of Pacific water to the Central Arctic.