Sources of Freshwater in the East Greenland Current, 2002, from Water Mass Analysis Using Oxygen Isotope Data

The East Greenland Current (EGC) transports freshwater from the Arctic Ocean via the climatically sensitive Nordic Seas to the subpolar North Atlantic. Assessing the leakage of freshwater from the EGC into the Nordic Seas is important because freshening in the surface of the Greenland and Iceland Seas inhibits convection and the renewal of dense intermediate and deep waters. A thorough understanding of the Arctic freshwater budget is also a prerequisite for predicting the future of Arctic sea ice. Here, the components of freshwater along six transects of the EGC are analyzed using a weighted, least-squares method that incorporates oxygen isotopes, salinity, nutrient and alkalinity data from 2002. The relative contributions of meteoric water, sea ice melt and Pacific water are quantified and contextualized within the freshwater budget of the Arctic. We also characterize the age structure of the EGC using helium isotopes.